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Taxon author: Hook.

ITIS records citing taxon author "Hook."
 
 Kingdom Animalia
  Cecidomyia foliora Russell and Hooker, 1908 -- invalid
  Gnathostenetroides pugio Hooker, 1985 -- valid
  Mesanthura hopkinsi Hooker, 1985 -- valid
  Metamunna wilsoni (Hooker, 1985) -- valid
  Mexicope Hooker, 1985 -- valid
  Mexicope kensleyi Hooker, 1985 -- valid
  Microjanira biunguiculata (Hooker, 1985) -- valid
  Munnogonium wilsoni Hooker, 1985 -- invalid
  Pleurocope floridensis Hooker, 1985 -- valid
 
 Kingdom Fungi
  Bacidia incompta (Borrer ex Hooker) Anzi -- accepted
  Dactylina arctica (Hook. f.) Nyl. -- accepted
  Masonhalea richardsonii (Hook.) Kärnefelt -- accepted
  Ramalina inflata (Hook. f. & T. Taylor) Hook. f. & T. Taylor -- accepted
 
 Kingdom Plantae
  Aberia caffra Hook. f. & Harv. -- not accepted
  Abies balsamea ssp. lasiocarpa (Hook.) B. Boivin -- not accepted
  Abies lasiocarpa (Hook.) Nutt. -- accepted -- balsam fir, Rocky Mountain fir, subalpine fir, western balsam fir, white balsam
  Abies lasiocarpa var. lasiocarpa (Hook.) Nutt. -- accepted -- subalpine fir
  Abronia fragrans Nutt. ex Hook. -- accepted -- heart's-delight, prairie snowball, snowball sand verbena, sweet sand verbena
  Abronia mellifera Douglas ex Hook. -- accepted -- white sand verbena
  Abutilon pictum (Gillies ex Hook. & Arn.) Walp. -- accepted -- painted Indian mallow
  Acacia cavenia (Molina) Hook. & Arn. -- not accepted
  Acacia pentagona (Schumach. & Thonn.) Hook. f. -- accepted
  Acanthonema Hook. f. -- accepted
  Acanthonema strigosum Hook. f. -- accepted
  Acer douglasii Hook. -- not accepted
  Acer drummondii Hook. & Arn. ex Nutt. -- not accepted
  Acer glabrum ssp. douglasii (Hook.) Wesm. -- not accepted
  Acer glabrum var. douglasii (Hook.) Dippel -- accepted -- Douglas' maple
  Acer rubrum ssp. drummondii (Hook. & Arn. ex Nutt.) E. Murray -- not accepted
  Acer rubrum var. drummondii (Hook. & Arn. ex Nutt.) Sarg. -- accepted -- Drummond's maple
  Achillea multiflora Hook. -- not accepted
  Achimenes argyrostigma Hook. -- not accepted
  Achimenes cupreata Hook. -- not accepted
  Achimenes fimbriata (Hook.) Hend. -- not accepted
  Achimenes mexicana (Seem.) Benth. & Hook. f. ex Fritsch -- accepted
  Achimenes ocellata Hook. -- not accepted
  Achimenes picta Benth. ex Hook. -- not accepted
  Achimenes tubiflora (Hook.) Britton -- not accepted
  Achneria Munro ex Benth. & Hook. f. -- not accepted
  Acleisanthes wrightii (A. Gray) Benth. & Hook. f. ex Hemsl. -- accepted -- Wright's trumpets
  Acmella pusilla (Hook. & Arn.) R.K. Jansen -- accepted -- dwarf spotflower
  Aconogonon campanulatum (Hook. f.) H. Hara -- accepted -- bellflower smartweed
  Acrobolbus anisodontus (Hook.f. & Taylor) Briscoe -- accepted
  Acrobolbus ochrophyllus (Hook.f. & Taylor) R.M. Schust. -- accepted
  Acrobolbus saccatus (Hook.) Trevis. -- accepted
  Acroclinium roseum Hook. -- not accepted
  Acrolasia albicaulis (Hook.) Rydb. -- not accepted
  Acrolejeunea mollis (Hook.f. & Taylor) Schiffn. -- accepted
  Acropeltis phyllophora Hooker and Harvey -- not accepted
  Acroschisma (Hook. f. & Wilson) Lindl. -- accepted
  Actinea richardsonii (Hook.) Kuntze -- not accepted
  Actinostachys pennula (Sw.) Hook. -- accepted -- ray fern, ray spiked fern
  Adelanthus falcatus (Hook.) Mitt. -- accepted
  Adelanthus occlusus (Hook.f. & Taylor) Carrington -- accepted
  Adenocaulon Hook. -- accepted -- trailplant
  Adenocaulon bicolor Hook. -- accepted -- American trailplant
  Adenophorus hymenophylloides Hook. & Grev. -- accepted -- filmy kihifern
  Adenophorus tamariscinus (Kaulf.) Hook. & Grev. -- accepted -- wahini noho mauna
  Adenophorus tamariscinus var. tamariscinus (Kaulf.) Hook. & Grev. -- accepted -- wahini noho mauna
  Adenostoma Hook. & Arn. -- accepted -- chamise
  Adenostoma fasciculatum Hook. & Arn. -- accepted -- chamise
  Adenostoma fasciculatum var. fasciculatum Hook. & Arn. -- accepted -- chamise, common chamise
  Adesmia angustifolia Hook. & Arn. -- not accepted
  Adesmia microphylla Hook. & Arn. -- accepted -- pahuen, palhuen, varilla
  Adesmia tenella Hook. & Arn. -- accepted
  Adiantopsis pedata (Hook.) T. Moore -- accepted
  Adiantum wilsonii Hook. -- accepted -- Wilson's maidenhair
  Aeschynanthus bracteatus var. peelii (Hook. f. & Thomson) C.B. Clarke -- not accepted
  Aeschynanthus cordifolius Hook. -- accepted
  Aeschynanthus hildebrandii Hemsl. ex Hook. f. -- not accepted
  Aeschynanthus javanicus Rollinson ex Hook. -- not accepted
  Aeschynanthus lobbianus Hook. -- not accepted
  Aeschynanthus miniatus var. cordifolius (Hook.) C.B. Clarke -- not accepted
  Aeschynanthus peelii Hook. f. & Thomson -- not accepted
  Aeschynanthus speciosus Hook. -- accepted
  Aeschynanthus tricolor Hook. -- accepted
  Agalmyla tuberculata Hook. f. -- accepted
  Agastache cana (Hook.) Wooton & Standl. -- accepted -- mosquito plant
  Agave maculosa Hook. -- not accepted
  Ageratina occidentalis (Hook.) King & H. Rob. -- accepted -- western eupatorium, western joepyeweed, western snakeroot
  Aglaonema commutatum var. maculatum (Hook. f.) Nicolson -- accepted -- Philippine evergreen
  Agoseris aurantiaca (Hook.) Greene -- accepted -- orange agoseris, orange-flowered false-dandelion
  Agoseris aurantiaca var. aurantiaca (Hook.) Greene -- accepted -- Mill Creek agoseris, orange agoseris
  Agoseris hirsuta (Hook.) Greene -- not accepted
  Agrimonia eupatoria var. parviflora Hook. -- not accepted
  Agropyron dasystachyum (Hook.) Vasey -- not accepted
  Agropyron dasystachyum (Hook.) Scribn. -- not accepted
  Agropyron dasystachyum var. dasystachyum (Hook.) Scribn. -- not accepted
  Agropyron dasystachyum var. subvillosum (Hook.) Scribn. & J.G. Sm. -- not accepted
  Agropyron repens ssp. pungens (Pers.) Hook. f. -- not accepted
  Agropyron subvillosum (Hook.) E.E. Nelson -- not accepted
  Agrostis antarctica Hook. f. -- not accepted
  Agrostis canina var. falklandica (Hook. f.) Hack. -- not accepted
  Agrostis canina var. falklandica (Hook. f.) Macloskie -- not accepted
  Agrostis canina var. falklandica (Hook. f.) Hack. ex Skottsb. -- not accepted
  Agrostis drummondii Torr. ex Hook. f. -- not accepted
  Agrostis exarata ssp. minor (Hook.) C.L. Hitchc. -- not accepted
  Agrostis exarata var. minor Hook. -- not accepted -- minor spike bentgrass
  Agrostis falklandica Hook. f. -- not accepted
  Agrostis foliata Hook. f. -- accepted
  Agrostis magellanica var. antarctica (Hook. f.) Pilg. -- not accepted
  Agrostis magellanica var. antartica (Hook. f.) Franch. -- not accepted
  Agrostis multiculmis Hook. f. -- not accepted
  Agrostis prostrata Hook. f. -- not accepted
  Agrostis spica-venti ssp. interrupta (L.) Hook. f. -- not accepted
  Agrostis tenuifolia var. fretensis Hook. f. -- not accepted
  Agrostis vulgaris var. nigra (With.) Hook. f. -- not accepted
  Aira antarctica Hook. f. -- not accepted
  Aira atropurpurea var. magellanica (Hook. f.) Skottsb. -- not accepted
  Aira caespitosa ssp. alpina (L.) Hook. f. -- not accepted
  Aira elongata Hook. -- not accepted
  Aira kingii Hook. f. -- not accepted
  Aira latifolia Hook. -- not accepted
  Aira magellanica Hook. f. -- not accepted
  Aira parvula Hook. f. -- not accepted
  Allamanda neriifolia Hook. -- not accepted
  Allium acuminatum Hook. -- accepted -- taper-tip onion, tapertip onion
  Allium douglasii Hook. -- accepted -- Douglas' onion
  Allium falcifolium Hook. & Arn. -- accepted -- scytheleaf onion
  Allocarya scouleri (Hook. & Arn.) Greene -- not accepted
  Alloplectus aureonitens (Hook.) Stearn -- not accepted
  Alloplectus capitatus Hook. -- not accepted
  Alloplectus concolor Hook. -- not accepted
  Alloplectus discolor Hook. f. -- not accepted
  Alloplectus eriocalyx Galeotti ex Hook. -- not accepted
  Alloplectus lynchii Hook. f. -- not accepted
  Alloplectus repens Hook. -- not accepted
  Alloplectus speciosus hort. ex Hook. -- not accepted
  Aloe deltoidea Hook.f. -- not accepted
  Aloina brevirostris (Hook. & Grev.) Kindb. -- accepted -- aloina moss
  Alopecurus alpinus var. aristatus Hook. f. -- not accepted
  Alopecurus alpinus var. gracilior Hook. f. -- not accepted
  Alopecurus elatior Jacq. ex Hook. f. -- not accepted
  Aloysia gratissima (Gillies & Hook.) Tronc. -- accepted -- whitebrush
  Aloysia gratissima var. gratissima (Gillies & Hook.) Tronc. -- accepted -- whitebrush
  Alsia californica (Hook. & Arnott) Sull. -- accepted -- California alsia moss
  Alsophila aneitensis (Hook.) R.M. Tryon -- not accepted
  Alsophila borbonica var. latifolia (Hook.) J.P. Roux -- not accepted
  Alsophila colensoi Hook. f. -- not accepted
  Alsophila cunninghamii (Hook. f.) R.M. Tryon -- not accepted
  Alsophila gigantea Wall. ex Hook. -- not accepted
  Alsophila imrayana (Hook.) D.S. Conant -- not accepted
  Alsophila kirkii (Hook.) R.M. Tryon -- not accepted
  Alsophila latebrosa Wall. ex Hook. -- not accepted
  Alsophila lurida (Blume) Hook. -- not accepted
  Alsophila manniana (Hook.) R.M. Tryon -- not accepted
  Alsophila milnei (Hook. ex Hook. f.) R.M. Tryon -- not accepted
  Alsophila salvinii Hook. -- not accepted
  Alsophila sinuata (Hook. & Grev.) R.M. Tryon -- not accepted
  Alsophila smithii (Hook. f.) R.M. Tryon -- not accepted
  Alsophila welwitschii (Hook.) R.M. Tryon -- not accepted
  Alternanthera echinocephala (Hook. f.) Christoph. -- accepted -- seaurchin joyweed
  Amblyopappus Hook. & Arn. -- accepted -- amblyopappus
  Amblyopappus pusillus Hook. & Arn. -- accepted -- dwarf coastweed
  Amblystegium irriguum (Hook. & Wils.) Schimp. in B.S.G. -- not accepted
  Ambrosia acanthicarpa Hook. -- accepted -- annual bursage, bursage, bursage ragweed, flat-spine burr-ragweed, flatspine bur ragweed, flatspine burr ragweed, sand bursage
  Amelanchier alnifolia var. semiintegrifolia (Hook.) C.L. Hitchc. -- accepted -- Pacific serviceberry, Saskatoon serviceberry
  Amelanchier ovalis var. semiintegrifolia Hook. -- not accepted
  Ampelothamnus phillyreifolius (Hook.) Small -- not accepted
  Amphibromus nervosus (Hook. f.) Baill. -- accepted
  Amphiglottis pallidiflora (Hook.) Britton -- not accepted
  Amsinckia vernicosa Hook. & Arn. -- accepted -- green fiddleneck
  Amsinckia vernicosa var. vernicosa Hook. & Arn. -- accepted -- green fiddleneck
  Amygdalus glandulosa Hook. -- not accepted
  Anastrepta orcadensis (Hook.) Schiffn. -- accepted
  Anastrophyllum donianum (Hook.) Steph. -- not accepted
  Anastrophyllum donnianum (Hook.) Steph. -- accepted
  Andreaea mutabilis Hook.f. & Wils. -- accepted -- andreaea moss
  Andreaea nivalis Hook. -- accepted -- andreaea moss
  Andrewsianthus perigonialis (Hook.f. & Taylor) R.M. Schust. -- accepted
  Andromeda phillyreifolia Hook. -- not accepted
  Andropogon jwarancusa ssp. laniger (Desf.) Hook. f. -- not accepted
  Andropogon sorghum var. vulgaris (Pers.) Stapf ex Hook. f. -- not accepted
  Andropogon tahitensis Hook. & Arn. -- not accepted
  Anemidictyon J. Sm. ex Hook. -- not accepted
  Anemone deltoidea Hook. -- accepted -- Columbian windflower
  Anemone richardsonii Hook. -- accepted -- yellow thimbleweed
  Anemopsis Hook. & Arn. -- accepted -- yerba mansa
  Anemopsis californica (Nutt.) Hook. & Arn. -- accepted -- yerba mansa, yerba-mansa
  Anemopsis californica var. californica (Nutt.) Hook. & Arn. -- not accepted -- yerba mansa
  Anetanthus alatus (Cham. & Schltdl.) Benth. & Hook. f. ex E.A. Durand & B.D. Jacks. -- not accepted
  Aneura multifida var. submersa (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- not accepted
  Aneura pinguis var. angustior (Hook.) Dumort. -- not accepted
  Aneura sinuata (Dicks. ex Hook.) Dumort. -- not accepted
  Angelonia gardneri Hook. -- accepted
  Anigozanthos pulcherrimus Hook. -- accepted
  Anisophyllum multiforme (Gaudich. ex Hook. & Arn.) Klotzsch & Garcke -- not accepted
  Anoda lanceolata Hook. & Arn. -- accepted -- lanceleaf anoda
  Anomodon Hook. & Tayl. -- accepted -- anomodon moss
  Anomodon viticulosus (Hedw.) Hook. & Tayl. -- accepted -- anomodon moss
  Anomylia cuneifolia (Hook.) R.M. Schust. -- not accepted
  Anotis foetida (Dalzell) Hook. f. -- not accepted
  Anotites menziesii (Hook.) Greene -- not accepted
  Antennaria carpathica var. lanata Hook. -- not accepted
  Antennaria carpathica var. pulcherrima Hook. -- not accepted
  Antennaria carpatica var. humilis Hook. -- not accepted
  Antennaria carpatica var. lanata Hook. -- not accepted
  Antennaria carpatica var. pulcherrima Hook. -- not accepted
  Antennaria lanata (Hook.) Greene -- accepted -- woolly pussytoes
  Antennaria pulcherrima (Hook.) Greene -- accepted -- showy pussytoes
  Antennaria pulcherrima ssp. pulcherrima (Hook.) Greene -- accepted -- handsome pussy-toes, showy pussy-toes
  Antennaria racemosa Hook. -- accepted -- raceme pussytoes
  Anthoceros punctatus var. laevis (L.) Hook. & Taylor ex Lindenb. -- not accepted
  Anthoceros punctatus var. major (Smith) Hook. & Wilson -- not accepted
  Antigonon leptopus Hook. & Arn. -- accepted -- confederate vine, coral vine, Mexican coral vine, Mexican creeper, queen's jewels, queen's wreath
  Antirhea lucida (Sw.) Hook. f. -- not accepted -- palo iloron
  Aphanorhegma serrata (Hooker & Wilson) Sullivant -- accepted
  Aphanorrhegma serratum (Hook.f. & Wils. in Drumm.) Sull. in Gray -- accepted -- serrate aphanorrhegma moss
  Aphyllon pinorum (Geyer ex Hook.) A. Gray -- not accepted
  Apium echinatum (Nutt. ex DC.) Benth. & Hook. f. ex S. Watson -- not accepted
  Aplozia sphaerocarpa (Hook.) Dumort. -- not accepted
  Apodanthera mathewsii Arn. ex Hook. -- accepted
  Aquilegia brevistyla Hook. -- accepted -- smallflower columbine
  Aquilegia caerulea var. ochroleuca Hook. -- not accepted -- white Colorado columbine
  Aquilegia canadensis var. hybrida Hook. -- not accepted
  Aquilegia coerulea var. ochroleuca Hook. -- accepted -- white Colorado columbine
  Arabidopsis arenicola (Richardson ex Hook.) Al-Shehbaz, Elven, D.F. Murray & Warwick -- accepted
  Arabis arenicola (Richardson ex Hook.) Gelert -- not accepted -- sand rockcress
  Arabis blepharophylla Hook. & Arn. -- accepted -- coast rockcress, rose rockcress
  Aragallus splendens (Douglas ex Hook.) Greene -- not accepted
  Aralia papyrifera Hook. -- not accepted -- Chinese rice-paper plant, rice-paper plant
  Araucaria bidwillii Hook. -- accepted -- bunya bunya
  Araucaria columnaris (G. Forst.) Hook. -- accepted -- New Caledonia pine
  Arenaria franklinii Douglas ex Hook. -- not accepted -- Franklin's sandwort, fringed sagewort
  Arenaria franklinii var. franklinii Douglas ex Hook. -- not accepted -- Franklin's sandwort
  Arenaria macrophylla Hook. -- not accepted
  Arenaria michauxii (Fenzl) Hook. f. -- not accepted
  Arenaria peploides var. major Hook. -- not accepted
  Arnica cordifolia Hook. -- accepted -- heart-leaf leopardbane, heartleaf arnica
  Arnica mollis Hook. -- accepted -- hairy arnica, wooly arnica
  Arnoglossum reniforme (Hook.) H. Rob. -- accepted -- great Indian plantain
  Artemisia borealis ssp. purshii (Hook.) Hultén -- not accepted
  Artemisia borealis var. purshii Hook. -- not accepted
  Artemisia campestris ssp. borealis var. purshii (Hook.) Cronq. -- not accepted -- Pursh's wormwood
  Artemisia campestris ssp. borealis var. scouleriana (Hook.) Cronquist -- not accepted -- field sagewort
  Artemisia campestris ssp. borealis var. wormskioldii (Besser ex Hook.) Cronquist -- not accepted -- field sagewort
  Artemisia campestris var. purshii (Hook.) Cronquist -- not accepted
  Artemisia campestris var. scouleriana (Hook.) Cronq. -- not accepted -- field sagewort
  Artemisia campestris var. wormskioldii (Besser ex Hook.) Cronquist -- not accepted -- field sagewort, northern wormwood
  Arthraxon inermis Hook. f. -- not accepted
  Asarina stricta (Hook. & Arn.) Pennell -- not accepted
  Asclepias vestita Hook. & Arn. -- accepted -- woolly milkweed
  Asclepias vestita ssp. vestita Hook. & Arn. -- accepted -- woolly milkweed
  Askellia elegans (Hook.) W.A. Weber -- not accepted
  Aspidotis (Nutt. ex Hook.) Copel. -- accepted -- lacefern
  Aspidotis californica (Hook.) Nutt. ex Copel. -- accepted -- California lacefern
  Asplenium acuminatum Hook. & Arn. -- accepted -- tapertip spleenwort
  Asplenium dalhousiae Hook. -- accepted -- Countess Dalhousie's spleenwort
  Asplenium macraei Hook. & Grev. -- accepted -- MaCrae's spleenwort
  Asplenium varians Wall. ex Hook. & Grev. -- accepted -- variable spleenwort
  Aster attenuatus auct. non Lindl. ex Hook. -- not accepted
  Aster attenuatus (Howell) M. Peck non Lindl. ex Hook. -- not accepted
  Aster filaginifolius Hook. & Arn. -- not accepted
  Aster major (Hook.) Porter -- not accepted
  Aster patens var. gracilis Hook. -- not accepted -- late purple aster
  Aster pinnatifidus (Hook.) Kuntze -- not accepted
  Aster sibiricus var. giganteus (Hook.) A. Gray -- not accepted -- giant arctic aster
  Aster tibeticus Hook. f. -- not accepted
  Aster tomentellus (Greene) Frye & Rigg non Hook. -- not accepted
  Aster unalaschkensis var. major Hook. -- not accepted
  Aster vahlii (Gaudich.) Hook. & Arn. -- not accepted
  Asterella australis (Hook.f. & Taylor) Verd. -- accepted
  Astomum phascoides (Hook. ex Drumm.) Grout -- accepted -- astomum moss
  Astragalus aboriginorum var. glabriusculus (Hook.) Rydb. -- not accepted
  Astragalus adsurgens ssp. robustior (Hook.) S.L. Welsh -- not accepted
  Astragalus adsurgens var. robustior Hook. -- not accepted -- prairie milkvetch
  Astragalus americanus (Hook.) M.E. Jones -- accepted -- American milk-vetch, American milkvetch, astragale d'Amérique
  Astragalus astragalinus (Hook.) Á. Löve & D. Löve -- not accepted
  Astragalus australis var. glabriusculus (Hook.) Isely -- accepted -- aboriginal milkvetch
  Astragalus bisulcatus (Hook.) A. Gray -- accepted -- two-groove milkvetch, twogrooved milkvetch
  Astragalus bisulcatus var. bisulcatus (Hook.) A. Gray -- accepted -- two-groove milk-vetch, twogrooved milkvetch
  Astragalus collinus (Hook.) Douglas ex G. Don -- accepted -- hillside milkvetch
  Astragalus collinus var. collinus (Hook.) Douglas ex G. Don -- accepted -- hillside milkvetch
  Astragalus diaphanus Douglas ex Hook. -- accepted -- transparent milkvetch
  Astragalus didymocarpus Hook. & Arn. -- accepted -- dwarf white milkvetch
  Astragalus didymocarpus var. didymocarpus Hook. & Arn. -- accepted -- dwarf white milkvetch
  Astragalus drummondii Douglas ex Hook. -- accepted -- Drummond milkvetch, Drummond's milk-vetch, Drummond's milkvetch
  Astragalus flexuosus var. elongatus (Hook.) M.E. Jones -- not accepted
  Astragalus frigidus var. americanus (Hook.) S. Watson -- not accepted
  Astragalus glareosus Douglas ex Hook. -- not accepted
  Astragalus hypoglottis Hook. -- not accepted
  Astragalus inflexus Douglas ex Hook. -- accepted -- bent milkvetch
  Astragalus laxmannii var. robustior (Hook.) Barneby & S.L. Welsh -- accepted -- prairie milkvetch
  Astragalus lentiginosus Douglas ex Hook. -- accepted -- freckled milkvetch, speckledpod milkvetch
  Astragalus lentiginosus var. lentiginosus Douglas ex Hook. -- accepted -- freckled milkvetch, speckledpod milkvetch
  Astragalus lotiflorus Hook. -- accepted -- lotus milk-vetch, lotus milkvetch, low milkvetch, milkvetch
  Astragalus macrodon (Hook. & Arn.) A. Gray -- accepted -- Salinas milkvetch
  Astragalus miser Douglas ex Hook. -- accepted -- timber milkvetch, weedy milkvetch
  Astragalus miser var. miser Douglas ex Hook. -- accepted -- timber milkvetch
  Astragalus pectinatus (Douglas ex Hook.) Douglas ex G. Don -- accepted -- narrowleaf milkvetch
  Astragalus polaris (Seem.) Benth. ex Hook. f. -- accepted -- polar milkvetch
  Astragalus purshii Douglas ex Hook. -- accepted -- Pursh loco, Pursh's milk-vetch, Pursh's milkvetch, woollypod milkvetch
  Astragalus purshii var. glareosus (Douglas ex Hook.) Barneby -- accepted -- gravel milkvetch, woollypod milkvetch
  Astragalus purshii var. purshii Douglas ex Hook. -- accepted -- Pursh's milk-vetch, Pursh's milkvetch, woollypod milkvetch
  Astragalus robbinsii var. minor (Hook.) Barneby -- accepted -- Robbins' milkvetch
  Astragalus splendens (Douglas ex Hook.) Tidestr. -- not accepted
  Astragalus succumbens Douglas ex Hook. -- accepted -- Columbia milkvetch
  Astrolepis integerrima (Hook.) D.M. Benham & Windham -- accepted -- hybrid cloakfern, hybrid lipfern
  Atamisquea Miers ex Hook. & Arn. -- accepted
  Atamisquea emarginata Miers ex Hook. & Arn. -- accepted -- atamisquea, vomitbush
  Atelophragma elegans (Hook.) Rydb. -- not accepted
  Athernotus longifolius (Hook.) Lunell -- not accepted
  Atheropogon affinis (Hook. f.) E. Fourn. -- not accepted
  Athroostachys capitata (Hook.) Benth. -- accepted
  Athyrium macraei (Hook. & Grev.) Copel. -- not accepted
  Athysanus pusillus (Hook.) Greene -- accepted -- common sandweed, dwarf anthysanus
  Atriplex gmelini var. zosterifolia (Hook.) Moq. -- not accepted
  Atriplex gmelinii var. zosterifolia (Hook.) Moq. -- not accepted
  Atriplex gordonii Hook. -- not accepted
  Atriplex oatula var. zosterifolia (Hook.) C.L. Hitchc. -- not accepted
  Atriplex patula var. zosterifolia (Hook.) C.L. Hitchc. -- not accepted
  Atriplex spinosa (Hook.) Collotzi -- not accepted
  Atropis magellanica (Hook. f.) E. Desv. -- not accepted
  Avena leptostachys Hook. f. -- not accepted
  Avena sativa var. sericea Hook. f. -- not accepted
  Azaleastrum albiflorum (Hook.) Rydb. -- not accepted
  Baeria californica (Hook.) K.L. Chambers -- not accepted
  Balantiopsis diplophylla (Hook.f. & Taylor) Mitt. -- accepted
  Balantiopsis diplophylla var. diplophylla (Hook.f. & Taylor) Mitt. -- accepted
  Balantiopsis erinacea (Hook.f. & Taylor) Mitt. -- accepted
  Balsamorhiza hookeri (Hook.) Nutt. -- accepted -- hairy balsamroot, Hooker's balsamroot, neglected balsamroot, rabbithead balsamroot
  Balsamorhiza hookeri var. hookeri (Hook.) Nutt. -- not accepted -- Hooker's balsamroot
  Balsamorhiza X terebinthacea (Hook.) Nutt. (pro sp.) -- accepted -- balsamroot
  Barbula indica (Hook.) Spreng. in Steud. -- accepted -- barbula moss
  Barbula indica var. indica (Hook.) Spreng. in Steud. -- accepted -- barbula moss
  Barosma crenulata (L.) Hook. -- not accepted
  Batidophaca lotiflora (Hook.) Rydb. -- not accepted
  Batidophaca lotiflorus (Hook.) Rydb. -- not accepted
  Begonia coccinea Hook. -- accepted -- scarlet begonia
  Berberis darwinii Hook. -- accepted -- Darwin's berberis
  Bergia texana (Hook.) Seub. ex Walp. -- accepted -- Texas bergia
  Berginia virgata Harv. ex Benth. & Hook. f. -- not accepted
  Berlandiera betonicifolia (Hook.) Small -- not accepted
  Berlandiera texana var. bentonicifolia (Hook.) Torr. & A. Gray -- not accepted
  Berlandiera texana var. betonicifolia (Hook.) Torr. & A. Gray -- not accepted
  Berlandiera X betonicifolia (Hook.) Small (pro sp.) -- accepted -- berlandiera, Texas greeneyes
  Besleria imrayi Hook. f. -- not accepted
  Besleria leucostoma (Hook.) Hanst. -- accepted
  Besleria lutea var. imrayi (Hook. f.) Urb. -- not accepted
  Besleria mollis Hook. ex Steud. -- not accepted
  Besseya rubra (Douglas ex Hook.) Rydb. -- not accepted -- red besseya, red kittentail
  Betula occidentalis Hook. -- accepted -- water birch
  Betula papyrifera ssp. occidentalis (Hook.) Hultén -- not accepted
  Betula papyrifera var. occidentalis (Hook.) Sarg. -- not accepted
  Bifora americana Benth. & Hook. f. ex S. Watson -- accepted -- prairie bishop
  Blechnum occidentale var. minor Hook. -- accepted -- hammock fern
  Blechnum spicant var. elongatum (Hook.) B. Boivin -- not accepted
  Blennosperma nanum (Hook.) S.F. Blake -- accepted -- common stickyseed
  Blennosperma nanum var. nanum (Hook.) S.F. Blake -- accepted -- common stickyseed
  Blepharidophyllum densifolium (Hook.) Ĺngstr. ex C. Massal. -- accepted
  Blepharipappus Hook. -- accepted -- blepharipappus
  Blepharipappus scaber Hook. -- accepted -- blepharipappus, rough eyelashweed
  Blepharipappus scaber ssp. scaber Hook. -- not accepted -- rough eyelashweed
  Blyttia lyellii (Hook.) Endl. ex Gottsche Lindenb. & Nees -- not accepted
  Blyttia lyellii var. hibernica (Hook.) Nees -- not accepted
  Bobea timonioides (Hook. f.) Hillebr. -- accepted -- `ahakea
  Boehmeria densiflora Hook. & Arn. -- accepted
  Boehmeria grandis (Hook. & Arn.) A. Heller -- accepted -- Hawai'i false nettle
  Boerhavia coulteri (Hook. f.) S. Watson -- accepted -- Coulter's spiderling
  Boerhavia coulteri var. coulteri (Hook. f.) S. Watson -- accepted -- Coulter's spiderling
  Bolbitis fluviatilis (Hook.) Ching -- accepted
  Bouteloua pilosa (Hook. f.) Benth. ex S. Watson -- not accepted
  Bowenia Hook. ex Hook. f. -- accepted
  Bowenia spectabilis Hook. ex Hook. f. -- accepted
  Bowringia Hook. -- not accepted
  Boykinia ranunculifolia (Hook.) A. Gray -- not accepted
  Boykinia richardsonii (Hook.) Rothr. -- accepted -- Alaska boykinia, bear flower, Richardson's brookfoam
  Brachyloma pictum (Hook.) Oerst. -- not accepted
  Brachymenium erectum (Hook.) Marg. -- accepted -- erect brachymenium moss
  Brachymenium speciosum (Hook.f. & Wils.) Steere -- accepted -- brachymenium moss
  Brassica trilocularis (Roxb.) Hook. f. & Thomson -- not accepted
  Braunia secunda (Hook.) Schimp. in B.S.G. -- accepted -- braunia moss
  Braya alpina var. americana (Hook.) S. Watson -- not accepted
  Braya americana (Hook.) Fernald -- not accepted
  Braya arctica Hook. -- not accepted
  Braya humilis var. americana (Hook.) B. Boivin -- not accepted
  Braya pilosa Hook. -- accepted -- hairy braya
  Braya purpurascens ssp. pilosa (Hook.) Hultén -- not accepted
  Brickellia grandiflora (Hook.) Nutt. -- accepted -- mountain brickellbush, tasselflower brickellbush, tasselflower brickellia
  Briza stricta (Hook. & Arn.) Steud. -- not accepted
  Briza stricta var. stricta (Hook. & Arn.) Steud. -- not accepted
  Brizopyrum douglasii (Nees) Hook. & Arn. -- not accepted
  Brizopyrum spicatum (L.) Hook. & Arn. -- not accepted
  Bromopsis vulgaris (Hook.) Holub -- not accepted
  Bromus breviaristatus (Hook.) Thurb. ex Torr. -- not accepted
  Bromus carinatus Hook. & Arn. -- accepted -- California brome, mountain brome
  Bromus carinatus var. carinatus Hook. & Arn. -- accepted
  Bromus inermis ssp. pumpellianus var. purpurascens (Hook.) Wagnon -- not accepted -- pumpelly brome
  Bromus inermis var. purpurascens (Hook.) Wagnon -- not accepted
  Bromus oregonus Nutt. ex Hook. f. -- not accepted
  Bromus pictus Hook. f. -- not accepted
  Bromus purgans var. longispicatus Hook. -- not accepted
  Bromus purgans var. pallidus Hook. -- not accepted
  Bromus purgans var. purpurascens Hook. -- not accepted
  Bromus purgans var. vulgaris Hook. -- not accepted
  Bromus richardsonii var. pallidus (Hook.) Shear -- not accepted
  Bromus setifolius var. pictus (Hook. f.) J.A. Cámara -- not accepted
  Bromus setifolius var. pictus (Hook. f.) Skottsb. -- accepted
  Bromus vulgaris (Hook.) Shear -- accepted -- Columbia brome
  Brunfelsia hopeana (Hook.) Benth. -- not accepted
  Bryum andicola Hook. in Kunth -- not accepted
  Bryum marratii Hook.f. & Wils. ex Wils. -- accepted -- Marrat's bryum moss
  Bryum nitens Hook. -- not accepted
  Bryum speciosum (Hook.f. & Wils.) Mitt. -- not accepted
  Caesalpinia gilliesii (Wall. ex Hook.) D. Dietr. -- not accepted -- bird of paradise, bird-of-paradise, bird-of-paradise shrub, Mexican bird of paradise, paradise caesalpinia, paradise poinciana
  Cakile edentula (Bigelow) Hook. -- accepted -- American searocket
  Cakile edentula ssp. edentula (Bigelow) Hook. -- accepted -- American searocket
  Cakile edentula ssp. edentula var. edentula (Bigelow) Hook. -- not accepted -- American searocket
  Cakile edentula var. edentula (Bigelow) Hook. -- accepted -- American searocket
  Calamagrostis longifolia Hook. -- not accepted
  Calamagrostis pumila Hook. f. -- not accepted
  Calamintha coccinea (Nutt. ex Hook.) Benth. -- not accepted -- scarlet calamint
  Calamovilfa longifolia (Hook.) Hack. ex Scribn. & Southw. -- accepted -- prairie sandreed
  Calamovilfa longifolia var. longifolia (Hook.) Hack. ex Scribn. & Southw. -- accepted -- prairie sand-reed, prairie sandreed
  Calandrinia ciliata var. menziesii (Hook.) J.F. Macbr. -- not accepted
  Calanthera Hook. -- not accepted
  Calanthera dactyloides (Nutt.) Kunth ex Hook. -- not accepted
  California macrophylla (Hook. & Arn.) Aldasoro, C. Navarro, P. Vargas, L. Sáez & Aedo -- not accepted
  Callicostella scabriseta (Hook.) Jaeg. -- not accepted
  Callirhoe pedata (Nutt. ex Hook.) A. Gray -- accepted -- palmleaf poppymallow
  Callirhoe pedata auct. non (Nutt. ex Hook.) Gray -- not accepted -- palmleaf poppymallow
  Calochortus leichtlinii Hook. f. -- accepted -- Leichtlin's mariposa lily, smokey mariposa
  Calochortus tolmiei Hook. & Arn. -- accepted -- Tolmie star-tulip
  Calochortus uniflorus Hook. & Arn. -- accepted -- Monterey mariposa lily
  Calomnion Hook.f. -- accepted
  Calotheca stricta Hook. & Arn. -- not accepted
  Calotheca stricta var. stricta Hook. & Arn. -- not accepted
  Caltha novae-zelandiae Hook. f. -- accepted
  Calycanthus occidentalis Hook. & Arn. -- accepted -- California spicebush, California-allspice, western sweetshrub
  Calycularia hibernica (Hook.) Steph. -- not accepted
  Calystegia subacaulis Hook. & Arn. -- accepted -- hillside false bindweed
  Calystegia subacaulis ssp. subacaulis Hook. & Arn. -- accepted -- hillside false bindweed
  Camissonia boothii ssp. alyssoides (Hook. & Arn.) P.H. Raven -- not accepted -- alyssum evening primrose, alyssum evening-primrose, alyssum eveningprimrose
  Camissonia boothii ssp. decorticans (Hook. & Arn.) P.H. Raven -- not accepted -- shredding suncup
  Camissonia boothii var. alyssoides (Hook. & Arn.) N.H. Holmgren & P.K. Holmgren -- not accepted
  Camissonia boothii var. decorticans (Hook. & Arn.) Cronquist -- not accepted
  Camissonia graciliflora (Hook. & Arn.) P.H. Raven -- not accepted -- hill suncup
  Campanula scouleri Hook. ex A. DC. -- accepted -- pale bellflower
  Cananga (DC.) Hook. f. & Thomson -- accepted -- ilang-ilang
  Cananga odorata (Lam.) Hook. f. & Thomson -- accepted -- ilang-ilang, ylang-ylang
  Canavalia pubescens Hook. & Arn. -- accepted -- awikiwiki, lavafield jackbean
  Cardamine angulata Hook. -- accepted -- seaside bittercress
  Cardamine pratensis ssp. angustifolia (Hook.) O.E. Schulz -- not accepted
  Cardamine pratensis var. angustifolia Hook. -- not accepted -- cuckoo flower
  Cardiobatus nivalis (Douglas ex Hook.) Greene -- not accepted
  Carex arctata Boott ex Hook. -- accepted -- drooping woodland sedge
  Carex complanata Torr. & Hook. -- accepted -- blue sedge, hirsute sedge
  Carex gmelinii Hook. & Arn. -- accepted -- Gmelin's sedge
  Carex membranacea Hook. -- accepted -- fragile sedge
  Carex microdonta Torr. & Hook. -- accepted -- littletooth sedge
  Carex oxylepis Torr. & Hook. -- accepted -- sharpscale sedge
  Carex oxylepis var. oxylepis Torr. & Hook. -- not accepted -- sharpscale sedge
  Carica candamarcensis Hook. f. -- not accepted
  Carpopeltis phyllophora (Hooker and Harvey) Schmitz -- accepted
  Carum copticum (L.) Benth. & Hook. f. ex C.B. Clarke -- not accepted
  Carum gairdneri (Hook. & Arn.) A. Gray -- not accepted
  Carum petroselinum (L.) Benth. & Hook. f. -- not accepted
  Cassia gaudichaudii Hook. & Arn. -- not accepted
  Castalia elegans (Hook.) Greene -- not accepted
  Castanopsis chrysophylla (Douglas ex Hook.) A. DC. -- not accepted -- giant chinkapin
  Castelaria nicholsonii (Hook.) Small -- not accepted
  Castilleja affinis Hook. & Arn. -- accepted -- coast Indian paintbrush
  Castilleja affinis Hook. & Arn. -- not accepted
  Castilleja affinis ssp. affinis Hook. & Arn. -- accepted -- coast Indian paintbrush
  Castilleja ambigua Hook. & Arn. -- accepted -- johnny-nip
  Castilleja ambigua ssp. ambigua Hook. & Arn. -- accepted -- johnny-nip
  Castilleja foliolosa Hook. & Arn. -- accepted -- Texas Indian paintbrush
  Castilleja latifolia Hook. & Arn. -- accepted -- Monterey Indian paintbrush
  Castilleja latifolia Hook. & Arn. -- not accepted
  Castilleja miniata Douglas ex Hook. -- accepted -- giant red Indian paintbrush, great red Indian paintbrush, great red Indian-paintbrush, scarlet Indian paintbrush, scarlet paintbrush
  Castilleja miniata ssp. miniata Douglas ex Hook. -- accepted -- giant red Indian paintbrush
  Castilleja miniata var. miniata Douglas ex Hook. -- not accepted -- green Indian paintbrush
  Catabrosa magellanica Hook. f. -- not accepted
  Catabrosa pauciflora (Hook.) FRIES -- not accepted
  Cathartolinum berlandieri (Hook.) Small -- not accepted
  Cathartolinum multicaule (Hook.) Small -- not accepted
  Catopsis nitida (Hook.) Griseb. -- accepted -- Caribbean strap airplant, Catopsis brillante
  Caucalis microcarpa Hook. & Arn. -- not accepted
  Caulanthus flavescens (Hook.) Payson -- accepted -- yellow mustard
  Caulanthus lasiophyllus (Hook. & Arn.) Payson -- accepted -- California mustard
  Caulanthus lasiophyllus var. lasiophyllus (Hook. & Arn.) Payson -- not accepted -- coast range wild cabbage
  Caularthron bicornutum (Hook.) Raf. -- accepted
  Ceanothus cuneatus (Hook.) Nutt. -- accepted -- buckbrush
  Ceanothus cuneatus ssp. cuneatus (Hook.) Nutt. -- not accepted -- coast buckbrush
  Ceanothus cuneatus var. cuneatus (Hook.) Nutt. -- accepted -- buckbrush
  Ceanothus dentatus var. floribundus (Hook.) Trel. -- not accepted
  Ceanothus integerrimus Hook. & Arn. -- accepted -- deerbrush, deerbrush ceanothus
  Ceanothus oliganthus ssp. sorediatus (Hook. & Arn.) C.L. Schmidt -- not accepted
  Ceanothus oliganthus var. sorediatus (Hook. & Arn.) Hoover -- not accepted -- jim-brush
  Ceanothus sorediatus Hook. & Arn. -- accepted -- jimbrush
  Ceanothus velutinus Douglas ex Hook. -- accepted -- snowbrush ceanothus, snowbush
  Ceanothus velutinus ssp. velutinus Douglas ex Hook. -- not accepted -- tobacco brush
  Ceanothus velutinus var. velutinus Douglas ex Hook. -- accepted -- snowbrush ceanothus
  Ceanothus X lobbianus Hook. (pro. sp.) -- accepted -- lobbian ceanothus
  Ceanothus X veitchianus Hook. (pro. sp.) -- accepted -- Veitch's ceanothus
  Celmisia spectabilis Hook. f. -- accepted
  Centromadia pungens (Hook. & Arn.) Greene -- accepted -- pungent false tarplant
  Centromadia pungens ssp. pungens (Hook. & Arn.) Greene -- accepted -- common tarweed
  Centrosolenia bractescens Hook. -- not accepted
  Centrosolenia picta Hook. -- not accepted
  Cephalozia physocaula (Hook.f. & Taylor) Steph. -- accepted
  Cephalozia tubulata (Hook.f. & Taylor) Trevis. -- accepted
  Cephaloziella turneri (Hook.) Müll. Frib. -- accepted
  Cerastium arvense ssp. fuegianum (Hook. f.) Ugbor. -- not accepted -- field chickweed
  Cerastium arvense var. fuegianum Hook. f. -- not accepted
  Cerastium fuegianum (Hook. f.) A. Nelson -- not accepted
  Cerasus emarginata Douglas ex Hook. -- not accepted
  Cerasus ilicifolia Nutt. ex Hook. & Arn. -- not accepted
  Ceratochloa breviaristata Hook. -- not accepted
  Ceratochloa carinata (Hook. & Arn.) Tutin -- not accepted
  Ceratochloa grandiflora Hook. -- not accepted
  Ceratopteris pteridoides (Hook.) Hieron. -- accepted -- floating antlerfern
  Ceratotheca triloba (Bernh.) E. Mey. ex Hook. f. -- accepted -- wild foxglove
  Cercocarpus parvifolius Nutt. ex Hook. & Arn. -- not accepted
  Cereus lamairei Hook. -- not accepted
  Cereus lemairei Hook. -- not accepted
  Cereus russelianus (Hook.) Gardner ex Lem. -- not accepted
  Ceropegia attenuata Hook. -- accepted
  Ceropegia beddomei Hook. f. -- accepted
  Ceropegia bowkeri ssp. sororia (Harvey ex Hook. f.) R.A. Dyer -- not accepted
  Ceropegia decaisneana var. brevicollis (Hook. f.) H. Huber -- accepted
  Ceropegia elegans var. gardneri (Hook.) Huber -- accepted
  Ceropegia hookeri C.B. Clarke ex Hook. f. -- accepted
  Ceropegia hookeri var. hookeri C.B. Clarke ex Hook. f. -- not accepted
  Ceropegia intermedia var. wightii Hook. f. -- accepted
  Ceropegia lawii Hook. f. -- accepted
  Ceropegia oculata var. subhirsuta Hook. -- not accepted
  Ceropegia thwaitesii Hook. -- accepted
  Ceropegia vincaefolia Hook. -- not accepted
  Ceropegia vincifolia Hook. -- accepted
  Ceterach dalhousiae (Hook.) C. Chr. -- not accepted
  Chaenactis douglasii (Hook.) Hook. & Arn. -- accepted -- Douglas dustymaiden, Douglas' dustymaiden, Douglas' pincushion, dusty maiden, dusty-maiden
  Chaenactis douglasii var. achilleifolia (Hook. & Arn.) A. Gray -- not accepted
  Chaenactis douglasii var. douglasii (Hook.) Hook. & Arn. -- accepted -- Douglas' dustymaiden, dusty-maiden
  Chaenactis stevioides Hook. & Arn. -- accepted -- Esteve's pincushion, Steve's dusty maiden, Steve's dustymaiden, Steve's pincushion
  Chaerophyllum dasycarpum (Hook. ex S. Watson) Nutt. ex Small -- not accepted
  Chaerophyllum procumbens var. tainturieri (Hook.) J.M. Coult. & Rose -- not accepted
  Chaerophyllum tainturieri Hook. -- accepted -- chervil, hairy-fruit chervil, hairyfruit chervil
  Chaerophyllum tainturieri var. dasycarpum Hook. ex S. Watson -- accepted -- hairyfruit chervil
  Chaerophyllum tainturieri var. tainturieri Hook. -- accepted -- hairyfruit chervil
  Chamaesaracha grandiflora (Hook.) Fernald -- not accepted
  Chamaesyce amplexicaulis (Hook. f.) D.G. Burch -- not accepted
  Chamaesyce bifida (Hook. & Arn.) T. Kuros. -- not accepted
  Chamaesyce burmanica (Hook. f.) Soják -- not accepted
  Chamaesyce clarkeana (Hook. f.) Soják -- not accepted
  Chamaesyce clusiifolia (Hook. & Arn.) Arthur -- not accepted -- forest sandmat
  Chamaesyce emodi (Hook. f.) Soják -- not accepted
  Chamaesyce multiformis (Gaudich. ex Hook. & Arn.) Croizat & O. Deg. -- not accepted -- variable sandmat
  Chamaesyce multiformis var. multiformis (Gaudich. ex Hook. & Arn.) Croizat & O. Deg. -- not accepted -- variable sandmat
  Chamaesyce nummularia (Hook. f.) D.G. Burch -- not accepted
  Chamaesyce recurva (Hook. f.) D.G. Burch -- not accepted
  Chamaesyce vachellii (Hook. & Arn.) H. Hara -- not accepted
  Chamaesyce viminea (Hook. f.) D.G. Burch -- not accepted
  Chamaesyce wightiana (Hook. f.) V.S. Raju & P.N. Rao -- not accepted
  Chascolytrum strictum (Hook. & Arn.) E. Desv. -- not accepted
  Cheilanthes californica (Hook.) Mett. -- not accepted
  Cheilanthes decipiens (Hook.) W.H. Wagner -- not accepted
  Cheilanthes fendleri Hook. -- accepted -- Fendler's lipfern
  Cheilanthes integerrima (Hook.) Mickel -- not accepted
  Cheilanthes lindheimeri Hook. -- accepted -- fairy swords, fairyswords, Lindheimer's lipfern
  Cheilanthes wrightii Hook. -- accepted -- Wright's lip fern, Wright's lipfern
  Cheilolejeunea albovirens (Hook.f. & Taylor) E.A. Hodgs. -- accepted
  Cheilolejeunea ascensionis (Hook.f. & Taylor) Grolle -- accepted
  Cheilolejeunea implexicaulis (Hook.f. & Taylor) R.M. Schust. -- accepted
  Cheilolejeunea microscypha (Hook.f. & Taylor) M. Wigginton -- accepted
  Cheilolejeunea mimosa (Hook.f. & Taylor) R.M. Schust. -- accepted
  Cheilolejeunea rotalis (Hook.f. & Taylor) M. Wigginton -- accepted
  Cheilosandra leptopus Griff. ex Benth. & Hook. f. -- not accepted
  Cheirodendron platyphyllum (Hook. & Arn.) Seem. -- accepted -- lapalapa
  Cheirodendron platyphyllum ssp. platyphyllum (Hook. & Arn.) Seem. -- accepted -- lapalapa
  Chenopodium humile Hook. -- not accepted -- marshland goosefoot
  Chenopodium humile auct. non Hook. -- not accepted -- marshland goosefoot
  Chenopodium macrospermum Hook. f. -- not accepted
  Chenopodium macrospermum Hook. f. -- accepted -- largeseed goosefoot
  Chenopodium rubrum var. humile (Hook.) S. Watson -- accepted -- marshland goosefoot
  Chenopodium rubrum var. humile auct. non (Hook.) S. Watson -- not accepted
  Chiastocaulon conjugatum (Hook.) S.D.F. Patzak, M.A.M. Renner, Schäf.-Verw. & Heinrichs -- accepted
  Chionochloa antarctica (Hook. f.) Zotov -- accepted
  Chionochloa bromoides (Hook. f.) Zotov -- accepted
  Chionochloa conspicua ssp. cunninghamii (Hook. f.) Zotov -- accepted
  Chirita clarkei Hook. f. -- not accepted
  Chirita depressa Hook. f. -- accepted
  Chirita lacunosa (Hook. f.) B.L. Burtt -- accepted
  Chirita zeylanica Hook. -- accepted
  Chloris tetrastachys Hack. ex Hook. f. -- not accepted
  Chlorocrepis albiflora (Hook.) W.A. Weber -- not accepted
  Chlorocrepis tristis ssp. gracilis (Hook.) W.A. Weber -- not accepted
  Chlorophora tinctoria (L.) Gaudich. ex Benth. & Hook. f. -- not accepted -- fustictree
  Chrysolepis chrysophylla (Douglas ex Hook.) Hjelmq. -- accepted -- giant chinquapin
  Chrysolepis chrysophylla var. chrysophylla (Douglas ex Hook.) Hjelmq. -- accepted -- giant chinquapin
  Chrysopsis hispida (Hook.) DC. -- not accepted
  Chrysopsis villosa var. hispida (Hook.) A. Gray -- not accepted
  Chrysosplenium americanum Schwein. ex Hook. -- accepted -- American golden saxifrage, water-mat
  Chrysothamnus viscidiflorus (Hook.) Nutt. -- accepted -- Douglas rabbitbrush, Douglas' rabbitbrush, green rabbitbrush, yellow rabbitbrush
  Chrysothamnus viscidiflorus ssp. viscidiflorus (Hook.) Nutt. -- accepted -- Douglas' rabbitbrush, green rabbitbrush, yellow rabbitbrush
  Chrysothamnus viscidiflorus ssp. viscidiflorus var. viscidiflorus (Hook.) Nutt. -- not accepted -- Douglas' rabbitbrush, green rabbitbrush, yellow rabbitbrush
  Chrysothamnus viscidiflorus var. viscidiflorus (Hook.) Nutt. -- not accepted -- yellow rabbitbrush
  Cibotium glaucum (Sm.) Hook. & Arn. -- accepted -- hapu'u
  Cibotium menziesii Hook. -- accepted -- hapu'u li
  Cicuta maculata var. angustifolia Hook. -- accepted -- common water hemlock, poison parsnip, spotted cowbane, spotted parsley, spotted water hemlock, spotted water-hemlock, water hemlock
  Cirsium foliosum (Hook.) DC. -- accepted -- Drummond's thistle, elk thistle, leafy thistle, meadow thistle
  Cirsium remotifolium (Hook.) DC. -- accepted -- fewleaf thistle
  Cirsium remotifolium ssp. remotifolium (Hook.) DC. -- not accepted -- fewleaf thistle
  Cirsium remotifolium var. remotifolium (Hook.) DC. -- accepted -- fewleaf thistle, remote-leaved thistle
  Cladopodiella francisci (Hook.) Jřrg. -- not accepted
  Claopodium crispifolium (Hook.) Ren. & Card. -- accepted -- claopodium moss
  Clarkia rhomboidea Douglas ex Hook. -- accepted -- broadleaf clarkia, diamond clarkia, diamond fairyfan
  Clasmatocolea fulvella (Hook.f. & Taylor) Grolle -- accepted
  Clasmatocolea humilis (Hook.f. & Taylor) Grolle -- accepted
  Clasmatocolea humilis var. humilis (Hook.f. & Taylor) Grolle -- accepted
  Clasmatocolea inflexispina (Hook.f. & Taylor) J.J. Engel -- accepted
  Clasmatocolea notophylla (Hook.f. & Taylor) Grolle -- accepted
  Clasmatocolea obvoluta (Hook.f. & Taylor) Grolle -- accepted
  Clasmatocolea obvoluta var. obvoluta (Hook.f. & Taylor) Grolle -- accepted
  Clasmatocolea rigens (Hook.f. & Taylor) J.J. Engel -- accepted
  Clasmatocolea strongylophylla (Hook.f. & Taylor) Grolle -- accepted
  Clasmatocolea trachyopa (Hook.f. & Taylor) Grolle -- accepted
  Clasmatodon Hook. & Wils. in Wils. -- accepted -- clasmatodon moss
  Clasmatodon parvulus (Hampe) Hook. & Wils. ex Sull. in Gray -- accepted -- clasmatodon moss
  Clausena anisata (Willd.) Hook. f. -- accepted
  Claytonia linearis Douglas ex Hook. -- not accepted
  Claytonia parviflora Douglas ex Hook. -- accepted -- littleleaf springbeauty, streambank springbeauty
  Claytonia parviflora ssp. parviflora Douglas ex Hook. -- accepted -- streambank springbeauty
  Claytonia perfoliata var. parviflora (Douglas ex Hook.) Torr. -- not accepted
  Claytonia spathulata var. exigua (Torr. & A. Gray) Hook. & Arn. -- not accepted
  Cleistanthus Hook. f. ex Planch. -- accepted
  Cleome lutea Hook. -- not accepted -- yellow beeplant, yellow spiderflower
  Cleome lutea var. lutea Hook. -- not accepted -- yellow spiderflower
  Clinopodium coccineum (Nutt. ex Hook.) Kuntze -- accepted -- scarlet calamint
  Cnemidaria apiculata (Hook.) Stolze -- not accepted
  Cnemidaria lindenii (Hook.) R.M. Tryon -- not accepted
  Cnemidophacos pectinatus (Douglas ex Hook.) Rydb. -- not accepted
  Cneoridium Hook. f. -- accepted
  Cneoridium dumosum (Nutt.) Hook. f. ex Baill. -- accepted -- bush rue
  Cochlidium rostratum (Hook.) Maxon ex C. Chr. -- accepted -- beaked snailfern
  Codonaraphia calycosa (Hook.) Oerst. -- not accepted
  Coelarthron Hook. f. -- not accepted
  Coix lacryma-jobi var. ma-yuen (Rom. Caill.) Stapf ex Hook. f. -- accepted
  Coldenia nuttallii Hook. -- not accepted
  Coleosanthus grandiflorus (Hook.) Kuntze -- not accepted
  Collandra aureonitens (Hook.) Hanst. -- not accepted
  Collandra picta (Hook.) Lem. -- not accepted
  Collomia heterophylla Douglas ex Hook. -- accepted -- variableleaf collomia
  Colpodium arundinaceum (Trin.) Hook. -- not accepted
  Colpodium pauciflorum Hook. -- not accepted
  Columnea aureonitens Hook. -- not accepted
  Columnea capitata (Hook.) Kuntze -- not accepted
  Columnea crassifolia hort. ex Hook. -- not accepted
  Columnea major (Hook.) Hanst. -- not accepted
  Columnea minor (Hook.) Hanst. -- accepted
  Columnea repens (Hook.) Hanst. -- accepted
  Columnea villosa (Hook. & Arn.) Kuntze -- not accepted
  Colura calyptrifolia (Hook.) Dumort. -- accepted
  Comarostaphylis discolor (Hook.) Diggs -- accepted
  Commelina deficiens Hook. -- not accepted
  Condalia obovata Hook. -- not accepted
  Condalia obtusifolia (Hook. ex Torr. & A. Gray) Weberb. -- not accepted
  Conradia calycosa Hook. -- not accepted
  Conradia neglecta W. Hook. -- not accepted
  Convolvulus subacaulis (Hook. & Arn.) Greene -- not accepted
  Copiapoa streptocaulon (Hook.) Oosten -- not accepted
  Corallocarpus Welw. ex Benth. & Hook.f. -- accepted
  Corculum leptopum (Hook. & Arn.) Stuntz -- not accepted
  Corculum leptopus (Hook. & Arn.) Stuntz -- not accepted
  Cordyline banksii Hook. f. -- accepted -- ti ngahere
  Coreopsis grandiflora var. longipes (Hook.) Torr. & A. Gray -- not accepted -- largeflower tickseed
  Coreopsis longipes Hook. -- not accepted
  Coreopsis maritima (Nutt.) Hook. f. -- accepted -- sea dahlia
  Corethrogyne filaginifolia (Hook. & Arn.) Nutt. -- accepted -- California sandaster, common sandaster, whiteleaf sandaster
  Corethrogyne filaginifolia var. filaginifolia (Hook. & Arn.) Nutt. -- not accepted -- common sandaster
  Corethrogyne tomentella (Hook. & Arn.) Torr. & A. Gray -- not accepted
  Corispermum hyssopifolium var. rubricaule Hook. -- not accepted
  Correa backhouseana Hook. -- accepted
  Correa backhousiana Hook. -- not accepted -- Backhous fuchsia
  Corydalis scouleri Hook. -- accepted -- Scouler's fumewort
  Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson -- accepted -- lemonscented gum
  Corytholoma douglasii var. verticillatum (Hook.) Toursark. -- not accepted
  Corytholoma ellipticum (Hook.) Decne. -- not accepted
  Corytholoma lindleyi (Hook.) Decne. -- not accepted
  Corytholoma marchii (Wailes ex Hook.) Decne. -- not accepted
  Corytholoma strictum (Hook. & Arn.) Decne. -- not accepted
  Corytoplectus capitatus (Hook.) Wiehler -- accepted
  Coscinodon calyptratus (Hook. in Drumm.) C. Jens. ex Kindb. -- accepted -- coscinodon moss
  Cotoneaster microphyllus var. glacialis Hook. f. ex Wenz. -- accepted
  Cotula australis (Sieber ex Spreng.) Hook. f. -- accepted -- Australian waterbuttons
  Crantzia capitata (Hook.) Fritsch -- not accepted
  Crassula erecta (Hook. & Arn.) A. Berger -- not accepted
  Crataegus opaca Hook. & Arn. -- accepted -- apple haw, riverflat hawthorn, western mayhaw
  Crepis elegans Hook. -- accepted -- elegant hawksbeard
  Crinum latifolium var. zeylanicum (L.) Hook. f. -- not accepted
  Critesion pubiflorum (Hook. f.) Á. Löve -- not accepted
  Critesion pubiflorum ssp. pubiflorum (Hook. f.) Á. Löve -- not accepted
  Crocidium Hook. -- accepted -- spring-gold
  Crocidium multicaule Hook. -- accepted -- common spring-gold
  Crotalaria crassipes Hook. -- not accepted
  Crotalaria longirostrata Hook. & Arn. -- accepted -- longbeak rattlebox
  Croton acerifolius A. Cunn. ex Hook. -- not accepted
  Croton ardisioides Hook. f. -- not accepted
  Croton caudatus var. malaccanus Hook. f. -- not accepted
  Croton erythrostachys Hook. f. -- accepted
  Croton erythrostachys var. erythrostachys Hook. f. -- accepted
  Croton griffithii Hook. f. -- accepted
  Croton laevifolius Hook. f. -- not accepted
  Croton macraei Hook. f. -- not accepted
  Croton polystachyus Hook. & Arn. -- not accepted
  Croton scouleri Hook. f. -- accepted
  Croton scouleri var. macraei (Hook. f.) Müll. Arg. -- not accepted
  Croton scouleri var. scouleri Hook. f. -- accepted
  Croton setiger Hook. -- accepted -- dove weed, turkey mullein
  Croton setigerus Hook. -- not accepted -- dove weed
  Croton xalapensis Hook. f. -- not accepted
  Cryphaea nervosa (Hook. & Wils. in Drumm.) C. Müll. -- accepted -- cryphaea moss
  Cryptantha circumscissa (Hook. & Arn.) I.M. Johnst. -- accepted -- cushion catseye, cushion cryptantha, matted cryptantha
  Cryptantha circumscissa var. circumscissa (Hook. & Arn.) I.M. Johnst. -- accepted -- cushion catseye, cushion cryptantha
  Cryptantha muricata (Hook. & Arn.) A. Nelson & J.F. Macbr. -- accepted -- pointed catseye, pointed cryptantha, prickly cryptantha
  Cryptantha muricata var. muricata (Hook. & Arn.) A. Nelson & J.F. Macbr. -- not accepted -- pointed cryptantha
  Cryptochloa concinna (Hook. f.) Swallen -- accepted
  Cryptoloma pictum (Hook.) Hanst. -- not accepted
  Cryptoloma triflorum (Hook.) Hanst. -- not accepted
  Cryptolophocolea leucophylla (Hook.f. & Taylor) L. Söderstr. -- accepted
  Cryptolophocolea pallidovirens (Hook.f. & Taylor) L. Söderstr. -- accepted
  Cryptolophocolea spinifera (Hook.f. & Taylor) L. Söderstr. -- accepted
  Cryptomitrium tenerum (Hook.) Austin ex Underw. -- accepted
  Ctenitis honolulensis (Hook.) Copel. -- not accepted -- Honolulu lacefern
  Ctenitis squamigera (Hook. & Arn.) Copel. -- accepted -- Pacific lacefern, Pauoa
  Ctenolepis Hook. f. -- accepted
  Cucumeropsis edulis (Hook. f.) Cogn. -- not accepted
  Culcita coniifolia (Hook.) Maxon -- accepted
  Cunila coccinea Nutt. ex Hook. -- not accepted
  Cunninghamia lanceolata (Lamb.) Hook. -- accepted -- Chinese fir
  Curcuma australasica Hook. f. -- accepted
  Cuscuta californica Hook. & Arn. -- accepted -- California dodder, chaparral dodder
  Cuscuta californica var. californica Hook. & Arn. -- accepted -- California dodder, chaparral dodder
  Cuscuta umbrosa Beyr. ex Hook. -- accepted -- bigfruit dodder
  Cuscuta umbrosa auct. non Beyr. ex Hook. -- not accepted
  Cyathea alternans (Hook.) C. Presl -- accepted
  Cyathea aneitensis Hook. -- accepted
  Cyathea assimilis Hook. -- accepted
  Cyathea aterrima (Hook.) Domin -- accepted
  Cyathea borbonica var. latifolia (Hook.) Bonap. -- not accepted
  Cyathea brunoniana (Hook.) C.B. Clarke & Baker -- accepted
  Cyathea camerooniana Hook. -- accepted
  Cyathea camerooniana var. aethiopica (Welw. ex Hook.) Holttum -- accepted
  Cyathea camerooniana var. camerooniana Hook. -- accepted
  Cyathea caracasana var. chimborazensis (Hook.) R.M. Tryon -- accepted
  Cyathea caudata (Hook.) Copel. -- accepted
  Cyathea colensoi (Hook. f.) Domin -- accepted
  Cyathea conjugata (Spruce ex Hook.) Domin -- accepted
  Cyathea contaminans (Wall. ex Hook.) Copel. -- accepted
  Cyathea contaminans var. contaminans (Wall. ex Hook.) Copel. -- not accepted
  Cyathea cooperi (Hook. ex F. Muell.) Domin -- accepted -- Cooper's cyathea, scaly tree fern
  Cyathea crinita (Hook.) Copel. -- accepted
  Cyathea cunninghamii Hook. f. -- accepted -- gully tree fern, slender tree fern
  Cyathea decurrens (Hook.) Copel. -- accepted
  Cyathea decurrens var. decurrens (Hook.) Copel. -- accepted
  Cyathea dregei var. burkei (Hook.) Sim -- accepted
  Cyathea gardneri Hook. -- accepted
  Cyathea gigantea (Wall. ex Hook.) Holttum -- accepted
  Cyathea imrayana Hook. -- accepted
  Cyathea imrayana var. imrayana Hook. -- accepted
  Cyathea imrayana var. subnudata Hook. -- not accepted
  Cyathea integra J. Sm. ex Hook. -- accepted
  Cyathea integra var. integra J. Sm. ex Hook. -- not accepted
  Cyathea integra var. petiolata (Hook.) -- not accepted
  Cyathea kirkii Hook. -- accepted
  Cyathea latebrosa (Wall. ex Hook.) Copel. -- accepted
  Cyathea lepifera (J. Sm. ex Hook.) Copel. -- accepted
  Cyathea lindsayana Hook. -- accepted
  Cyathea manniana Hook. -- accepted
  Cyathea milnei Hook. -- accepted
  Cyathea multiflora var. hostmannii (Hook.) -- not accepted
  Cyathea munita Willd. ex Hook. -- accepted
  Cyathea petiolata (Hook.) R.M. Tryon -- accepted
  Cyathea phegopteroides (Hook.) Domin -- accepted
  Cyathea platylepis (Hook.) Domin -- accepted
  Cyathea podophylla (Hook.) Copel. -- accepted
  Cyathea poeppigii (Hook.) Domin -- accepted
  Cyathea ramispina (Hook.) Copel. -- accepted
  Cyathea sagittifolia (Hook.) Domin -- accepted
  Cyathea salvinii (Hook.) Domin -- accepted
  Cyathea sinuata Hook. & Grev. -- accepted
  Cyathea smithii Hook. f. -- accepted -- soft tree fern
  Cyathea spinulosa Wall. ex Hook. -- accepted
  Cyathea sprucei Hook. -- not accepted
  Cyathea tenera (J. Sm. ex Hook.) T. Moore -- accepted -- helecho gigante
  Cyathea walkerae Hook. -- accepted
  Cyathea walkerae var. tripinnata Hook. -- accepted
  Cyathea walkerae var. walkerae Hook. -- accepted
  Cyathea welwitschii Hook. -- accepted
  Cyathea X calolepis (Hook.) Domin -- accepted
  Cyathea X wilsonii (Hook.) Domin -- accepted
  Cymopterus terebinthinus (Hook.) Torr. & A. Gray -- not accepted
  Cynoglossum penicillatum Hook. & Arn. -- not accepted
  Cyperus acuminatus Torr. & Hook. ex Torr. -- accepted -- taper-tip flat sedge, taperleaf flatsedge, tapertip flatsedge
  Cyperus cephalanthus Torr. & Hook. -- accepted -- buttonbush flatsedge
  Cyperus drummondii Torr. & Hook. -- accepted -- Drummond's sedge
  Cyperus lutescens Torr. & Hook. -- not accepted
  Cyperus setigerus Torr. & Hook. -- accepted -- lean flatsedge
  Cyperus trachysanthos Hook. & Arn. -- accepted -- Pu`uka`a, sticky flatsedge
  Cyperus uniflorus Torr. & Hook., non Thunb. -- not accepted
  Cyperus virens var. drummondii (Torr. & Hook.) Kük. -- not accepted -- Drummond's flatsedge
  Cyrtandra biflora Hook. & Arn. -- not accepted
  Cyrtandra menziesii Hook. & Arn. -- accepted -- ha`iwale
  Cyrtandra oblongifolia (Blume) Benth. & Hook. f. ex C.B. Clarke -- accepted
  Cyrtandra triflora Hook. & Arn. -- not accepted
  Cyrtodeira cupreata (Hook.) Hanst. -- not accepted
  Cyrtodeira cupreata var. viridifolia Hook. -- not accepted
  Cyrtomium caryotideum (Wall. ex Hook. & Grev.) C. Presl -- accepted -- dwarf netvein hollyfern
  Cyrtopus (Brid.) Hook. f. -- accepted
  Cyrtorhyncha cymbalaria ssp. alpina (Hook.) Á. Löve & D. Löve -- not accepted
  Cystopteris douglasii Hook. -- accepted -- Douglas' bladderfern
  Dacrydium franklinii Hook. f. -- not accepted -- Huon pine
  Dalbergaria aureonitens (Hook.) Wiehler -- not accepted
  Dalbergia barclayi Telf. ex Hook. -- not accepted
  Dalea ornata (Douglas ex Hook.) Eaton & Wright -- accepted -- Blue Mountain prairie clover, showy prairieclover
  Daltonia Hook. & Tayl. -- accepted -- daltonia moss
  Daltonia splachnoides (Sm. in Sm. & Sowerby) Hook. & Tayl. -- accepted -- daltonia moss
  Daltonia splachnoiodes (J.E. Smith) Hooker & Taylor -- accepted
  Danthonia cachemyriana var. minor Hook. f. -- not accepted
  Danthonia cumminsii Hook. f. -- not accepted
  Danthonia jacquemontii var. minor (Hook. f.) Bor -- not accepted
  Danthonia nervosa Hook. f. -- not accepted
  Davallia fejeensis Hook. -- accepted -- lacy hare's-foot fern
  Delphinium burkei ssp. distichiflorum (Hook.) Ewan -- not accepted
  Delphinium burkei var. distichiflorum (Hook.) H. St. John -- not accepted
  Delphinium cardinale Hook. -- accepted -- scarlet larkspur
  Delphinium distichum Geyer ex Hook. -- accepted -- twospike larkspur
  Delphinium strictum var. distichiflorum (Hook.) H. St. John -- not accepted
  Dendroalsia abietina (Hook.) Britt. -- accepted -- dendroalsia moss
  Dendroceros adglutinatus (Hook. f. & Taylor) Gottsche -- accepted
  Dendroceros crispatus (Hook.) Nees -- accepted
  Dendroceros crispatus var. crispatus (Hook.) Nees -- accepted
  Dendromastigophora flagellifera (Hook.) R.M. Schust. -- accepted
  Deparia Hook. & Grev. -- accepted -- false spleenwort
  Deparia prolifera (Kaulf.) Hook. & Grev. -- accepted -- prolific false spleenwort
  Deschampsia airiformis (Steud.) Benth. & Hook. f. -- accepted
  Deschampsia atropurpurea var. latifolia (Hook.) Scribn. ex Macoun -- not accepted
  Deschampsia elongata (Hook.) Munro -- accepted -- slender hairgrass
  Deschampsia kingii (Hook. f.) E. Desv. -- accepted
  Deschampsia kingii (Hook. f.) Macloskie -- not accepted
  Deschampsia latifolia (Hook.) Vasey -- not accepted
  Deschampsia parvula (Hook. f.) Desv. -- accepted
  Descurainia incana var. major (Hook.) Dorn -- not accepted
  Descurainia sophioides (Fisch. ex Hook.) O.E. Schulz -- accepted -- northern tansymustard
  Desmatodon suberectus (Hook.) Limpr. -- not accepted
  Desmodium canescens var. hirsutum (Hook.) B.L. Rob. -- not accepted
  Desmodium cuneatum Hook. & Arn. -- accepted
  Deyeuxia aleutica (Trin.) Munro ex Hook. -- not accepted
  Deyeuxia anomala (Trin.) Benth. & Hook. f. -- not accepted
  Deyeuxia arundina Phil. ex Durand & Hook. f. -- not accepted
  Deyeuxia canadensis (Michx.) Munro ex Hook. -- not accepted
  Deyeuxia groenlandica Munro ex Hook. f. -- not accepted
  Deyeuxia sesquiflora (E. Desv.) Benth. & Hook. f. ex W.D. Jacks. -- not accepted
  Dianella sandwicensis Hook. & Arn. -- accepted -- `uki`uki
  Diastema ochroleucum Hook. -- not accepted
  Diastema pictum (Benth. ex Hook.) Walp. -- not accepted
  Dicentra chrysantha (Hook. & Arn.) Walp. -- accepted -- golden eardrops
  Dichelachne crinata (L. f.) Hook. f. -- not accepted -- clovenfoot plumegrass
  Dichelachne crinita (L. f.) Hook. f. -- accepted
  Dichelachne sciurea (R. Br.) Hook. f. -- not accepted
  Dicksonia menziesii (Hook.) Hook. & Baker -- not accepted
  Dicksonia sellowiana Hook. -- accepted
  Dicranodontium uncinatum (Harv. in Hook.) Jaeg. -- accepted -- dicranodontium moss
  Dicranum fulvum Hook. -- accepted -- dicranum moss
  Dicraurus Hook. f. -- not accepted
  Dicraurus leptocladus Hook. f. -- not accepted
  Didissandra rufa King ex Hook. f. -- not accepted
  Didymocarpus depressus (Hook. f.) Chun -- not accepted
  Didymocarpus incanus (R. Brown) Benth. & Hook. f. ex C.B. Clarke -- not accepted
  Didymocarpus lacunosus Hook. f. -- not accepted
  Didymocarpus malayanus Hook. f. -- not accepted
  Didymocarpus rexii Hook. -- not accepted
  Didymodon australasiae (Grev. & Hook.) Zand. -- not accepted
  Didymodon rigidulus var. gracilis (Schleich. ex Hook. & Grev.) Zand. -- accepted -- rigid didymodon moss
  Didymoglossum krausii (Hook. & Grev.) C. Presl -- accepted -- treemoss bristle fern
  Digitaria marginata var. ciliaris (Retz.) Hook. f. ex Ridl. -- not accepted
  Digitaria sanguinalis f. ciliaris (Retz.) Hook. f. ex Haines -- not accepted
  Diholcos bisulcatus (Hook.) Rydb. -- not accepted
  Dilaena hibernica (Hook.) Dumort. -- not accepted
  Dilaena lyellii (Hook.) Dumort. -- not accepted
  Dillenia ovata Wall. ex Hook. f. & Thomson -- accepted -- ovate dillenia
  Dillenia suffruticosa (Griffith ex Hook. f. & Thomson) Martelli -- accepted -- shrubby dillenia
  Dinckleria fruticella (Hook.f. & Taylor) J.J. Engel & Heinrichs -- accepted
  Dinckleria pleurata (Hook.f. & Taylor) Trevis. -- accepted
  Dioclea reflexa Hook. f. -- accepted
  Diplasiolejeunea plicatiloba (Hook.f. & Taylor) Grolle -- accepted
  Diplolaena hibernica (Hook.) Dumort. -- not accepted
  Diplolaena lyellii (Hook.) Dumort. -- not accepted
  Diplolaena lyellii var. hibernica (Hook.) Nees -- not accepted
  Diplomitrion hibernicum (Hook.) Corda -- not accepted
  Diplomitrion lyellii (Hook.) Corda -- not accepted
  Diplopappus pinnatifidus Hook. -- not accepted
  Diplophyllum obtusifolium (Hook.) Dumort. -- accepted
  Diplophyllum obtusifolium ssp. obtusifolium (Hook.) Dumort. -- accepted
  Dircaea bulbosa (Hook.) Lem. -- not accepted
  Dircaea fascialis (Hook.) Decne. -- not accepted
  Dircaea lateritia (Hook.) Decne. -- not accepted
  Dircaea picta (Hook.) Lem. -- not accepted
  Disporum smithii (Hook.) Piper -- not accepted -- largeflower fairybells
  Disporum trachycarpum (S. Watson) Benth. & Hook. f. -- not accepted -- rough-fruit fairybells, roughfruit fairybells, wartberry fairybells
  Distasis concinna Hook. & Arn. -- not accepted
  Dodecatheon dentatum Hook. -- not accepted -- white shootingstar
  Dodecatheon dentatum ssp. dentatum Hook. -- not accepted -- white shootingstar
  Dodonaea viscosa var. arborescens (A. Cunn. ex Hook.) Sherff -- not accepted
  Dolichodeira tubiflora (Hook.) Hanst. -- not accepted
  Doryopteris decipiens (Hook.) J. Sm. -- accepted -- triangleleaf lipfern
  Doryopteris decora var. decipiens (Hook.) R.M. Tryon -- not accepted
  Douglasia arctica Hook. -- not accepted -- Mackenzie River dwarf-primrose
  Douglasia ochotensis ssp. arctica (Hook.) Á. Löve & D. Löve -- not accepted
  Dovyalis caffra (Hook. f. & Harv.) Warb. -- accepted -- kei apple
  Draba alpina var. nana Hook. -- not accepted
  Draba micropetala Hook. -- accepted
  Draba oligosperma Hook. -- accepted -- fewseed draba, glacier draba
  Draba oligosperma var. oligosperma Hook. -- not accepted
  Drepanolejeunea hamatifolia (Hook.) Schiffn. -- accepted
  Drummondia Hook. ex Drumm. -- accepted -- drummond moss
  Drummondia clavellata Hook. in Drumm. -- not accepted
  Dryas drummondii Richardson ex Hook. -- accepted -- Drummond's mountain-avens
  Dryas drummondii var. drummondii Richardson ex Hook. -- not accepted -- Drummond's mountain-avens
  Dryas octopetala var. drummondii (Richardson ex Hook.) S. Watson -- not accepted
  Dryas octopetala var. integrifolia (Vahl) Hook. f. -- not accepted
  Drymonia marmorata Hook. f. -- not accepted
  Dryopteris crinalis (Hook. & Arn.) C. Chr. -- accepted -- serpent woodfern
  Dryopteris crinalis var. crinalis (Hook. & Arn.) C. Chr. -- accepted
  Dryopteris goldiana (Hook. ex Goldie) A. Gray -- accepted -- Goldie's woodfern
  Dryopteris sandwicensis (Hook. & Arn.) C. Chr. -- accepted -- Pacific woodfern
  Dryopteris unidentata (Hook. & Arn.) C. Chr. -- accepted -- onetooth woodfern
  Dryopteris unidentata var. unidentata (Hook. & Arn.) C. Chr. -- accepted
  Dubautia laxa Hook. & Arn. -- accepted -- na`ena`e pua melemele
  Dubautia laxa ssp. laxa Hook. & Arn. -- accepted -- na`ena`e pua melemele
  Dupontia fisheri var. flavescens Hook. & Arn. -- not accepted
  Dupontia psilosantha var. flavescens (Hook. & Arn.) Vasey -- not accepted
  Dyera Hook. f. -- accepted
  Dyera costulata (Miq.) Hook. f. -- accepted -- jelutong
  Echinocactus cinnabarinus Hook. -- not accepted
  Echinocactus pentlandii Hook. -- not accepted
  Echinocereus chlorophthalmus (Hook.) Britton & Rose -- not accepted
  Echinocereus pentlandii (Hook.) K. Schum. -- not accepted
  Echinochloa glabrescens Munro ex Hook. f. -- accepted
  Echinopsis cinnabarina (Hook.) Labour. -- accepted
  Echinopsis pentlandii (Hook.) Salm-Dyck ex A. Dietr. -- accepted
  Eggersia buxifolia Hook. f. -- not accepted
  Ehrendorferia chrysantha (Hook. & Arn.) Rylander -- not accepted -- golden eardrops
  Elaeocarpus bifidus Hook. & Arn. -- accepted -- kalia
  Elaphoglossum paleaceum (Hook. & Grev.) Sledge -- accepted
  Elatine texana (Hook.) Torr. & A. Gray -- not accepted
  Elymus antarcticus Hook. f. -- not accepted
  Elymus antarcticus var. antarcticus Hook. f. -- not accepted
  Elymus submuticus (Hook.) Smyth -- not accepted -- Virginia wildrye
  Elymus subvillosus (Hook.) Gould -- not accepted
  Elymus virginicus f. submuticus (Hook.) R.W. Pohl -- not accepted
  Elymus virginicus var. submuticus Hook. -- not accepted -- Virginia wildrye
  Elytrigia dasystachya (Hook.) Á. Löve & D. Löve -- not accepted
  Encephalartos horridus var. trispinosus Hook. -- not accepted
  Encephalartos trispinosus (Hook.) R.A. Dyer -- accepted
  Encyclia Hook. -- accepted -- butterfly orchid
  Encyclia pygmaea (Hook.) Dressler -- not accepted -- dwarf butterfly orchid, Encyclia pigmea
  Enemion occidentale (Hook. & Arn.) J.R. Drumm. & Hutch. -- accepted -- western false rue anemone
  Entodon brevisetus (Hook. & Wils. in Wils.) Lindb. -- accepted -- entodon moss
  Eotrichocolea polyacantha (Hook.f. & Taylor) R.M. Schust. -- accepted
  Eotrichocolea polycantha (Hook.f. & Taylor) R.M. Schust. -- not accepted
  Epidendrum bicornutum Hook. -- not accepted
  Epidendrum pallidiflorum Hook. -- accepted -- Caribbean star orchid
  Epidendrum parkinsonianum Hook. -- accepted
  Epidendrum pygmaeum Hook. -- not accepted
  Epidendrum viridipurpureum Hook. -- accepted
  Epilobium canum ssp. latifolium (Hook.) P.H. Raven -- accepted -- hummingbird trumpet
  Epilobium canum var. latifolium (Hook.) N.H. Holmgren & P.K. Holmgren -- not accepted
  Epipactis gigantea Douglas ex Hook. -- accepted -- giant helleborine, Heleborina gigante, stream orchid
  Episcia bicolor Hook. -- not accepted
  Episcia bractescens (Hook.) Hanst. -- not accepted
  Episcia chontalensis (Seem.) Hook. f. -- not accepted
  Episcia cupreata (Hook.) Hanst. -- accepted -- flame violet
  Episcia cupreata var. viridifolia (Hook.) Nichols. -- not accepted
  Episcia erythropus Hook. f. -- not accepted
  Episcia fulgida (Linden ex André) Hook. f. -- not accepted
  Episcia lynchii (Hook. f.) Knuth -- not accepted
  Episcia maculata Hook. f. -- not accepted
  Episcia picta (Hook.) Hanst. -- not accepted
  Eremocarpus setiger (Hook.) Benth. -- not accepted
  Eremocarpus setigerus (Hook.) Benth. -- not accepted -- doveweed, turkey mullein
  Eremogone franklinii (Douglas ex Hook.) R.L. Hartm. & Rabeler -- accepted -- Franklin's sandwort
  Eremogone franklinii var. franklinii (Douglas ex Hook.) R.L. Hartm. & Rabeler -- accepted -- Franklin's sandwort
  Eremothera boothii ssp. alyssoides (Hook. & Arn.) W.L. Wagner & Hoch -- accepted -- alyssum evening primrose
  Eremothera boothii ssp. decorticans (Hook. & Arn.) W.L. Wagner & Hoch -- accepted -- shredding suncup
  Erianthus elephantinus Hook. f. -- not accepted
  Ericameria viscidiflora (Hook.) L.C. Anderson -- not accepted
  Erigeron acris var. elatus (Hook.) Cronquist -- not accepted
  Erigeron alpinus var. elatus Hook. -- not accepted
  Erigeron asperum var. pubescens (Hook.) Breitung -- not accepted
  Erigeron compositus var. typicus Hook. -- not accepted
  Erigeron concinnus (Hook. & Arn.) Torr. & A. Gray -- accepted -- hairy daisy, Navajo fleabane
  Erigeron concinnus var. concinnus (Hook. & Arn.) Torr. & A. Gray -- accepted -- Navajo daisy, Navajo fleabane
  Erigeron elatus (Hook.) Greene -- accepted -- swamp boreal-daisy
  Erigeron filifolius (Hook.) Nutt. -- accepted -- threadleaf daisy, threadleaf fleabane
  Erigeron filifolius var. filifolius (Hook.) Nutt. -- not accepted -- threadleaf daisy, threadleaf fleabane
  Erigeron glabellus ssp. pubescens (Hook.) Cronquist -- not accepted
  Erigeron glabellus var. pubescens auct. non Hook. -- not accepted
  Erigeron glabellus var. pubescens Hook. -- accepted -- fleabane, streamside fleabane
  Erigeron grandiflorus Hook. -- accepted -- largeflower fleabane, onestem fleabane
  Erigeron grandiflorus ssp. grandiflorus Hook. -- not accepted -- largeflower fleabane
  Erigeron lanatus Hook. -- accepted -- hairy daisy, woolly fleabane
  Erigeron linearis (Hook.) Piper -- accepted -- desert yellow fleabane, linearleaf daisy
  Erigeron lonchophyllus Hook. -- accepted -- low-meadow fleabane, short-ray boreal-daisy, shortray boreal daisy, shortray fleabane, spearleaf daisy, vergerette ŕ feuilles fines
  Erigeron minor (Hook.) Rydb. -- not accepted
  Erigeron pumilus var. concinnus (Hook. & Arn.) Dorn -- not accepted
  Erigeron radiatus Hook. -- not accepted
  Erigeron radicatus Hook. -- accepted -- Huber's fleabane, tap-root fleabane, taproot fleabane
  Erigeron trifidus Hook. -- accepted -- Alberta fleabane
  Erigeron velutipes Hook. & Arn. -- accepted -- Chihuahuan fleabane
  Eriodictyon californicum (Hook. & Arn.) Torr. -- accepted -- California yerba santa
  Eriogonum compositum var. leianthum Hook. -- accepted -- arrowleaf buckwheat
  Eriogonum divaricatum Hook. -- accepted -- divergent buckwheat, divergent wild buckwheat
  Eriogonum microthecum ssp. laxiflorum (Hook.) S. Stokes -- not accepted
  Eriogonum microthecum var. laxiflorum Hook. -- accepted -- slender buckwheat
  Eriogonum pyrolifolium Hook. -- accepted -- Shasta buckwheat
  Eriogonum pyrolifolium var. pyrolifolium Hook. -- accepted -- Shasta buckwheat
  Eriogonum salsuginosum (Nutt.) Hook. -- not accepted
  Eriogonum umbellatum ssp. majus (Hook.) Piper -- not accepted
  Eriogonum umbellatum var. majus Hook. -- accepted -- sulphur-flower buckwheat
  Eriogonum umbellatum var. tolmieanum (Hook.) M.E. Jones -- not accepted
  Eriogynia Hook. -- not accepted
  Eriogynia pectinata (Pursh) Hook. -- not accepted
  Eriophyllum integrifolium (Hook.) Greene -- not accepted
  Eriophyllum lanatum var. integrifolium (Hook.) Smiley -- accepted -- common woolly sunflower, wholeleaf eriophyllum
  Erodium macrophyllum Hook. & Arn. -- accepted -- roundleaf stork's bill
  Erodium macrophyllum var. macrophyllum Hook. & Arn. -- accepted -- roundleaf stork's bill
  Eryngium articulatum Hook. -- accepted -- beethistle
  Eryngium divaricatum Hook. & Arn. -- accepted -- ballast eryngo
  Eryngium petiolatum Hook. -- accepted -- rushleaf eryngo
  Erysimum asperum var. capitatum (Douglas ex Hook.) B. Boivin -- not accepted
  Erysimum capitatum (Douglas ex Hook.) Greene -- accepted -- coast wallflower, sand dune wallflower, western wallflower
  Erysimum capitatum var. capitatum (Douglas ex Hook.) Greene -- accepted -- plains wallflower, prairie rocket, sand dune wallflower, western wallflower
  Erysimum menziesii (Hook.) Wettst. -- accepted -- Menzies' wallflower
  Erysimum menziesii ssp. menziesii (Hook.) Wettst. -- not accepted -- Menzies' wallflower
  Erythrostemon gilliesii (Wall. ex Hook.) Klotzsch -- accepted
  Escallonia macrantha Hook. & Arn. -- not accepted
  Escallonia rubra var. macrantha (Hook. & Arn.) Reiche -- accepted -- redclaws
  Eubrachion Hook. f. -- accepted -- tapeworm-plant
  Eubrachion ambiguum (Hook. & Arn.) Engl. -- accepted -- tapeworm-plant
  Eucalyptus citriodora Hook. -- not accepted -- lemonscented gum
  Eucalyptus coccifera Hook. f. -- accepted
  Eucalyptus gunnii Hook. f. -- accepted -- cider gum
  Eucalyptus macrocarpa Hook. -- accepted -- mottlecah
  Eucalyptus maculata Hook. -- accepted -- eucalyptus, spotted gum
  Eucalyptus nitida Hook. f. -- accepted -- Smithton peppermint gum
  Eucalyptus platypus Hook. -- accepted
  Eucalyptus risdonii Hook. f. -- accepted -- Risdon peppermint gum
  Eucalyptus spathulata Hook. -- accepted -- eucalyptus
  Eucalyptus spathulata ssp. spathulata Hook. -- accepted -- eucalyptus
  Eucalyptus urnigera Hook. f. -- accepted -- urn gum, urn-fruit gum
  Eucalyptus vernicosa Hook. f. -- accepted
  Eunanus nanus (Hook. & Arn.) Holz. -- not accepted
  Eunanus subuniflorus (Hook. & Arn.) Greene -- not accepted
  Eupatorium occidentale Hook. -- not accepted
  Euphorbia alata Hook. -- accepted
  Euphorbia ampla Hook. f. -- not accepted
  Euphorbia ampla var. tenuior Hook. f. -- not accepted
  Euphorbia amplexicaulis Hook. f. -- accepted
  Euphorbia beaumieriana Hook. f. & Coss. -- not accepted
  Euphorbia bifida Hook. & Arn. -- accepted
  Euphorbia bifida auct. non Hook. & Arn. -- not accepted
  Euphorbia burmanica Hook. f. -- accepted
  Euphorbia clarkeana Hook. f. -- accepted
  Euphorbia clusiifolia Hook. & Arn. -- accepted -- forest sandmat
  Euphorbia diffusa Hook. f. -- not accepted
  Euphorbia echinus Hook. f. & Coss. -- not accepted
  Euphorbia emodi Hook. f. -- not accepted
  Euphorbia eremophila A. Cunn. ex Hook. -- not accepted
  Euphorbia griffithii Hook. f. -- accepted
  Euphorbia griffithii var. griffithii Hook. f. -- accepted
  Euphorbia jacquiniiflora Hook. -- not accepted
  Euphorbia lathyris var. minor Hook. & Arn. -- not accepted
  Euphorbia milii var. splendens (Bojer ex Hook.) Ursch & Leandri -- accepted
  Euphorbia monteiroi Hook. -- accepted
  Euphorbia monteiroi ssp. monteiroi Hook. -- accepted
  Euphorbia multiformis Gaudich. ex Hook. & Arn. -- accepted -- variable sandmat
  Euphorbia multiformis var. multiformis Gaudich. ex Hook. & Arn. -- accepted -- variable sandmat
  Euphorbia myrtifolia Hook. & Arn. -- not accepted
  Euphorbia nummularia Hook. f. -- accepted
  Euphorbia obesa Hook. f. -- accepted
  Euphorbia obesa ssp. obesa Hook. f. -- accepted
  Euphorbia officinarum ssp. beaumieriana (Hook. f. & Coss.) Vindt -- accepted
  Euphorbia officinarum ssp. echinus (Hook. f. & Coss.) Vindt -- accepted
  Euphorbia officinarum var. beaumieriana (Hook. f. & Coss.) Maire -- not accepted
  Euphorbia pseudograntii (Hook. f.) Bruyns -- not accepted
  Euphorbia ramosissima Hook. & Arn. -- not accepted
  Euphorbia recurva Hook. f. -- accepted
  Euphorbia rotundifolia Hook. & Arn. -- not accepted
  Euphorbia splendens Bojer ex Hook. -- not accepted
  Euphorbia splendens ssp. bojeri (Hook.) Denis -- not accepted
  Euphorbia splendens var. bojeri (Hook.) Costantin & Gallaud -- not accepted
  Euphorbia strigosa Hook. & Arn. -- accepted
  Euphorbia tannensis ssp. eremophila (A. Cunn. ex Hook.) D.C. Hassall -- accepted
  Euphorbia tannensis var. eremophila (A. Cunn. ex Hook.) D.C. Hassall -- not accepted
  Euphorbia vachellii Hook. & Arn. -- not accepted
  Euphorbia viminea Hook. f. -- accepted
  Euphorbia wallichii Hook. f. -- accepted
  Euphorbia wightiana Hook. f. -- not accepted
  Eurybia sibirica var. gigantea (Hook.) G.L. Nesom -- not accepted
  Eustoma exaltatum ssp. russellianum (Hook.) Kartesz -- accepted -- showy prairie gentian
  Eustoma russellianum (Hook.) G. Don -- not accepted -- showy prairiegentian
  Eutrema arenicola Richardson ex Hook. -- not accepted
  Eutriana affinis Hook. f. -- not accepted
  Eutriana gracilis Hook. f. -- not accepted
  Eutriana pilosa Hook. f. -- not accepted
  Exacum inflatum Hook. & Arn. -- not accepted
  Fabronia ciliaris var. polycarpa (Hook.) Buck -- accepted -- fabronia moss
  Fadyenia Hook. -- accepted -- dotted fern
  Fatsia horrida (Sm.) Benth. & Hook. f. ex W.H. Brewer & S. Watson -- not accepted
  Fauria crista-galli (Menzies ex Hook.) Makino -- not accepted -- deercabbage
  Ferula macrocarpa Hook. & Arn. -- not accepted
  Festuca antarctica var. g Hook. f. -- not accepted
  Festuca arundo Hook. f. -- not accepted
  Festuca distichophylla (Labill.) Hook. f. -- not accepted
  Festuca fuegiana Hook. f. -- not accepted
  Festuca fuegiana var. vivipara Hook. -- not accepted
  Festuca gracillima Hook. f. -- accepted
  Festuca gracillima subvar. gracillima Hook. f. -- not accepted
  Festuca gracillima var. gracillima Hook. f. -- accepted
  Festuca nervosa Hook. -- not accepted
  Festuca occidentalis Hook. -- accepted -- western fescue
  Festuca occidentalis var. occidentalis Hook. -- not accepted
  Festuca ovina ssp. rubra Hook. -- not accepted
  Festuca purpurascens Banks & Sol. ex Hook. f. -- accepted
  Festuca purpurascens var. purpurascens Banks & Sol. ex Hook. f. -- not accepted
  Festuca richardsonii Hook. -- not accepted -- Richardson's fescue
  Festuca rubra ssp. richardsonii (Hook.) Hultén -- not accepted
  Festuca tolucensis var. hephaestophila (Nees ex Steud.) Nees ex Hook. -- not accepted
  Filicium Thwaites ex Benth. & Hook. f. -- accepted
  Fimbristylis drummondii (Torr. & Hook. ex Torr.) Boeckeler -- not accepted
  Fimbristylis puberula var. drummondii (Torr. & Hook.) D.B. Ward -- not accepted
  Fissidens hyalinus Wils. & Hook. -- accepted -- fissidens moss
  Fitchia Hook. f. -- accepted -- fitchia
  Fitzroya Hook. f. ex Lindl. -- accepted
  Fitzroya patagonica Hook. f. ex Lindl. -- not accepted
  Flagellaria plicata Hook. f. -- not accepted
  Fontinalis disticha Hook. & Wils. in Drumm. -- not accepted
  Forasaccus breviaristatus (Hook.) Lunell -- not accepted
  Fragaria chiloensis var. scouleri Hook. -- not accepted
  Franseria acanthicarpa (Hook.) Coville -- not accepted
  Fraxinus dipetala Hook. & Arn. -- accepted -- California ash, two-petal ash
  Fraxinus mariesii Hook. f. -- not accepted -- Maries' ash
  Froelichia gracilis (Hook.) Moq. -- accepted -- slender snake-cotton, slender snakecotton
  Frullania aterrima (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Frullania clavata (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Frullania congesta (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Frullania fugax (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Frullania lobulata (Hook.) Hook. & Nees -- accepted
  Frullania monocera (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Frullania monocera var. monocera (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Frullania pycnantha (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Frullania rostrata (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Frullania squarrosula (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Fuscocephaloziopsis albescens (Hook.) Vána & L. Söderstr. -- accepted
  Fuscocephaloziopsis albescens var. albescens (Hook.) Vána & L. Söderstr. -- accepted
  Gaertneria acanthicarpa (Hook.) Britton -- not accepted
  Gaillardia drummondii (Hook.) DC. -- not accepted
  Galanthus elewesii Hook. f. -- not accepted
  Galanthus elwesii Hook. f. -- accepted -- giant snowdrop
  Galium aparine var. minor Hook. -- not accepted
  Galium californicum Hook. & Arn. -- accepted -- California bedstraw
  Galium californicum ssp. californicum Hook. & Arn. -- accepted -- California bedstraw
  Garcinia hanburyi Hook. f. -- accepted -- Hanbury's garcinia
  Garcinia xanthochymus Hook. f. ex T. Anderson -- accepted -- garcinia
  Garrya fadyenia Hook. -- not accepted -- Fadyen's silktassel
  Garrya fadyenii Hook. -- accepted
  Gastrolychnis drummondii (Hook.) Á. Löve & D. Löve -- not accepted
  Gaultheria pyroloides Hook. f. & Thomson ex Miquel -- accepted -- Japanese wintergreen, Miquel's spicywintergreen
  Gaura decorticans Hook. & Arn. -- not accepted
  Gayophytum diffusum var. strictipes (Hook.) Dorn -- not accepted
  Gayophytum micranthum Hook. & Arn. -- accepted
  Gayophytum ramosissimum var. strictipes Hook. -- not accepted
  Gentiana crinita var. browniana (Hook.) B. Boivin -- not accepted
  Geoffroea decorticans (Gillies ex Hook. & Arn.) Burkart -- accepted -- chańar
  Geranium cuneatum Hook. -- accepted -- hinahina
  Geranium cuneatum ssp. cuneatum Hook. -- accepted -- hinahina
  Geranium cuneatum var. cuneatum Hook. -- not accepted -- hinahina
  Geranium glabratum (Hook.) Small -- not accepted
  Geranium microphyllum Hook. f. -- not accepted
  Geranium traversii Hook. f. -- accepted -- cranesbill
  Gerbera jamesonii Bolus ex Hook. f. -- accepted -- Barberton daisy
  Gesneria auriculata (Hook.) Kuntze -- not accepted
  Gesneria bulbosa var. lateritia Hook. -- not accepted
  Gesneria calycosa (Hook.) Kuntze -- accepted
  Gesneria cochlearis Hook. -- not accepted
  Gesneria douglasii var. verticillata (Hook.) Hook. -- not accepted
  Gesneria elliptica Hook. -- not accepted
  Gesneria elliptica var. lutea Hook. -- not accepted
  Gesneria gardneri Hook. -- not accepted
  Gesneria lindleyi Hook. -- not accepted
  Gesneria marchii Wailes ex Hook. -- not accepted
  Gesneria neglecta (W. Hook.) Kuntze -- not accepted
  Gesneria pardina Hook. -- not accepted
  Gesneria picta Hook. -- not accepted
  Gesneria picta var. minus-hirsuta Hook. -- not accepted
  Gesneria pumila ssp. neglecta (W. Hook.) L.E. Skog -- accepted
  Gesneria schiedeana (DC.) Hook. -- not accepted
  Gesneria seemannii Hook. -- not accepted
  Gesneria stricta Hook. & Arn. -- not accepted
  Gesneria triflora Hook. -- not accepted
  Gesneria tubiflora (Hook.) Griseb. -- not accepted
  Gesneria verticillata Hook. -- not accepted
  Giesleria picta (Benth. ex Hook.) Regel -- not accepted
  Gilia congesta Hook. -- not accepted
  Gilia gracilis Hook. -- not accepted
  Gilia gracilis var. humilior (Hook.) H. St. John -- not accepted
  Gilia pungens var. hookeri (Douglas ex Hook.) A. Gray -- not accepted
  Gilia squarrosa (Eschsch.) Hook. & Arn. -- not accepted
  Gladiolus papilio Hook. f. -- accepted -- goldblotch gladiolus
  Glandularia incisa (Hook.) Tronc. -- accepted -- crisped mock vervain
  Gleichenia glauca (Thunb. ex Houtt.) Hook. -- not accepted
  Gleichenia owhyensis Hook. -- not accepted
  Gleichenia owhyhensis Hook. -- not accepted
  Gloxinia hypocyrtiflora Hook. f. -- not accepted
  Gloxinia maculata var. pallidiflora (Hook.) Bedd. -- not accepted
  Gloxinia pallidiflora Hook. -- not accepted
  Gloxinia sarmentiana Gardner ex Hook. -- not accepted
  Gloxinia speciosa var. albiflora Hook. -- not accepted
  Gloxinia speciosa var. macrophylla Hook. -- not accepted
  Gloxinia speciosa var. menziesii Hook. -- not accepted
  Gloxinia tubiflora Hook. -- not accepted
  Glyceria arctica Hook. -- not accepted
  Glyceria distans ssp. conferta (Fr.) Hook. f. -- not accepted
  Glyceria distans var. arctica (Hook.) Gelert ex N.W. Simmonds -- not accepted
  Glyceria magellanica (Hook. f.) Benth. -- not accepted
  Glyceria maritima var. arctica (Hook.) Kurtz -- not accepted
  Gnaphalium alienum Hook. & Arn. -- not accepted
  Godetia parviflora (Hook. & Arn.) Jeps. -- not accepted
  Goebelobryum unguiculatum (Hook.f. & Taylor) Grolle -- accepted
  Gonystylus maingayi Hook. f. -- accepted
  Goodyera decipiens (Hook.) F.T. Hubb. -- not accepted
  Gordonia spathulifolia (Hook.) Á. Löve & D. Löve -- not accepted
  Gormania spathulifolia (Hook.) Á. Löve & D. Löve -- not accepted
  Gossypianthus Hook. -- accepted -- cottonflower
  Gossypianthus lanuginosus var. tenuiflorus (Hook.) Henrickson -- accepted -- woolly cottonflower
  Gossypianthus rigidiflorus Hook. -- not accepted
  Gossypianthus tenuiflorus Hook. -- not accepted
  Gouinia E. Fourn. ex Benth. & Hook. f. -- accepted
  Gouldia terminalis (Hook. & Arn.) Hillebr. -- not accepted
  Gouldia terminalis var. coriacea (Hook. & Arn.) Fosberg -- not accepted
  Gourliea decorticans Gillies ex Hook. & Arn. -- not accepted
  Grammica umbrosa auct. non (Beyr. ex Hook.) W.A. Weber -- not accepted
  Grammitis rostrata (Hook.) R.M. Tryon & A.F. Tryon -- not accepted
  Grayia Hook. & Arn. -- accepted -- hopsage
  Grayia spinosa (Hook.) Moq. -- accepted -- spiny hopsage
  Greeneocharis circumscissa (Hook. & Arn.) Rydb. -- not accepted
  Greyia Hook. & Harv. -- accepted -- Natal bottlebrush
  Grimmia apocarpa var. stricta (Turn.) Hook. & Tayl. -- not accepted
  Grimmia calyptrata Hook. in Drumm. -- not accepted
  Grimmia pulvinata var. africana (Hedw.) Hook.f. -- accepted -- African dry rock moss
  Grimmia unicolor Hook. in Grev. -- accepted -- onecolor dry rock moss
  Grindelia grandiflora Hook. -- accepted -- manyray gumweed
  Grindelia hirsutula Hook. & Arn. -- accepted -- bract gumweed, hairy gumweed, sharpleaf gumweed
  Grindelia hirsutula ssp. hirsutula Hook. & Arn. -- not accepted -- hairy gumweed
  Grindelia hirsutula var. hirsutula Hook. & Arn. -- not accepted -- hairy gumweed
  Grindelia humilis Hook. & Arn. -- not accepted
  Grossularia californica (Hook. & Arn.) Coville & Britton -- not accepted
  Guilleminea lanuginosa (Poir.) Moq. ex Benth. & Hook. f. -- not accepted
  Guilleminea lanuginosa var. rigidiflora (Hook.) Mears -- not accepted
  Guilleminea lanuginosa var. tenuiflora (Hook.) Mears -- not accepted
  Guillenia flavescens (Hook.) Greene -- not accepted -- yellow mustard
  Guillenia lasiophylla (Hook. & Arn.) Greene -- not accepted -- California mustard, coast wild cabbage, hairyleaf wildcabbage
  Gymnocalycium leeanum (Hook.) Britton & Rose -- not accepted
  Gymnocalycium mackieanum (Hook.) Metzing, Mereg. & R. Kiesling -- not accepted
  Gymnocalycium multiflorum (Hook.) Britton & Rose -- not accepted
  Gymnocalycium reductum var. leeanum (Hook.) Papsch -- accepted
  Gymnomitrion lyellii (Hook.) Huebener -- not accepted
  Gymnomitrion sinuatum (Dicks. ex Hook.) Huebener -- not accepted
  Gymnosphaera ramispina (Hook.) Copel. -- not accepted
  Gymnosteris nudicaulis (Hook. & Arn.) Greene -- accepted -- nakedstem gymnosteris
  Habenaria alata Hook. -- accepted -- Habenaria alada, winged bog orchid
  Habenaria blephariglottis (Willd.) Hook. -- not accepted
  Habenaria dilatata (Pursh) Hook. -- not accepted
  Habenaria orbiculata (Pursh) Hook. -- not accepted
  Halimolobos mollis (Hook.) Rollins -- not accepted -- soft fissurewort
  Halophila ovalis (R. Br.) Hook. f. -- accepted -- seagrass
  Haplopappus carthamoides (Hook.) A. Gray -- not accepted
  Haplopappus ericoides (Less.) Hook. & Arn. -- not accepted
  Haplopappus ericoides var. ericoides (Less.) Hook. & Arn. -- not accepted
  Haplopappus lanceolatus (Hook.) Torr. & A. Gray -- not accepted
  Haplopappus lanceolatus var. lanceolatus (Hook.) Torr. & A. Gray -- not accepted
  Haplopappus squarrosus Hook. & Arn. -- not accepted
  Haplopappus squarrosus var. squarrosus Hook. & Arn. -- not accepted
  Haplopappus uniflorus (Hook.) Torr. & A. Gray -- not accepted
  Haplopappus uniflorus var. uniflorus (Hook.) Torr. & A. Gray -- not accepted
  Harpalejeunea marginalis (Hook.f. & Taylor) Steph. -- accepted
  Harpalejeunea parasitica (Hook.f. & Taylor) Steph. -- accepted
  Hazardia squarrosa (Hook. & Arn.) Greene -- accepted -- sawtooth goldenbush
  Hazardia squarrosa var. squarrosa (Hook. & Arn.) Greene -- accepted -- sawtooth goldenbush
  Hedyotis caerulea (L.) Hook. -- not accepted
  Hedyotis centranthoides (Hook. & Arn.) Steud. -- not accepted -- forest starviolet
  Hedyotis longifolia (Gaertn.) Hook. -- not accepted
  Hedyotis terminalis (Hook. & Arn.) W.L. Wagner & D.R. Herbst -- not accepted -- variable starviolet
  Helianthella quinquenervis (Hook.) A. Gray -- accepted -- fivenerve helianthella, nodding dwarf-sunflower, nodding helianthella
  Helianthus quinquenervis Hook. -- not accepted
  Heliconia metallica Planch. & Linden ex Hook. -- accepted -- shining bird of paradise, shining bird-of-paradise
  Heliopsis minor (Hook.) C. Mohr -- not accepted
  Heliotropium anomalium Hook. & Arn. -- not accepted
  Heliotropium anomalum Hook. & Arn. -- accepted -- Polynesian heliotrope
  Heliotropium anomalum var. anomalum Hook. & Arn. -- accepted -- Polynesian heliotrope
  Helipterum roseum (Hook.) Benth. -- not accepted
  Helminthostachys zeylanica (L.) Hook. -- accepted -- kamraj
  Hemieva ranunculifolia (Hook.) Raf. -- not accepted
  Hemitelia hostmanii Hook. -- not accepted
  Hemitelia wilsonii Hook. -- not accepted
  Hemizonia multicaulis Hook. & Arn. -- not accepted
  Hemizonia multicaulis var. multicaulis Hook. & Arn. -- not accepted
  Hemizonia pugens (Hook. & Arn.) Torr. & A. Gray -- not accepted
  Hemizonia pugens var. pugens (Hook. & Arn.) Torr. & A. Gray -- not accepted
  Hemizonia pungens (Hook. & Arn.) Torr. & A. Gray -- not accepted -- common spikeweed, common tarweed, spikeweed
  Hemizonia pungens ssp. pungens (Hook. & Arn.) Torr. & A. Gray -- not accepted -- common tarweed, spikeweed
  Henckelia malayana (Hook. f.) A. Weber -- accepted
  Henckelia rexii (Hook.) Heynh. -- not accepted
  Hepatostolonophora rotata (Hook.f. & Taylor) J.J. Engel -- accepted
  Hepatostolonophora rotata var. rotata (Hook.f. & Taylor) J.J. Engel -- accepted
  Herzogobryum atrocapillum (Hook.f. & Taylor) Grolle -- accepted
  Hesperoxalis trilliifolia (Hook.) Small -- not accepted
  Heterocentron Hook. & Arn. -- accepted
  Heterogemma capitata (Hook.) Konstant. & Vilnet -- accepted
  Heterophyllium affine (Hook. in Kunth) Fleisch. -- accepted -- heterophyllium moss
  Heteroscyphus allodontus (Hook.f. & Taylor) J.J. Engel & R.M. Schust. -- accepted
  Heteroscyphus chlorophyllus (Hook.f. & Taylor) Schiffn. -- accepted
  Heteroscyphus coalitus (Hook.) Schiffn. -- accepted
  Heteroscyphus coalitus var. coalitus (Hook.) Schiffn. -- accepted
  Heteroscyphus fissistipus (Hook.f. & Taylor) Schiffn. -- accepted
  Heteroscyphus fissistipus var. fissistipus (Hook.f. & Taylor) Schiffn. -- accepted
  Heteroscyphus oblongifolius (Hook.f. & Taylor) Schiffn. -- accepted
  Heteroscyphus planiusculus (Hook.f. & Taylor) J.J. Engel -- accepted
  Heteroscyphus polycladus (Hook.f. & Lév.) R.M. Schust. -- accepted
  Heteroscyphus sinuosus (Hook.) Schiffn. -- accepted
  Heteroscyphus supinus (Hook.f. & Taylor) R.M. Schust. -- accepted
  Heteroscyphus triacanthus (Hook.f. & Lév.) Schiffn. -- accepted
  Heteroscyphus triacanthus var. triacanthus (Hook.f. & Lév.) Schiffn. -- accepted
  Heterostega curtipendula Schwein. ex Hook. f. -- not accepted
  Heterotheca villosa var. hispida (Hook.) V.L. Harms -- not accepted -- bristly hairy goldaster
  Heterotheca villosa var. horrida (Hook.) Semple -- not accepted
  Heterotheca villosa var. minor (Hook.) Semple -- accepted -- hairy false goldenaster
  Hibiscus furcellatus var. youngianus (Gaudich. ex Hook. & Arn.) Hochr. -- accepted -- lindenleaf rosemallow
  Hibiscus schizopetalus (Dyer) Hook. f. -- accepted -- fringed rosemallow
  Hibiscus youngianus Gaudich. ex Hook. & Arn. -- not accepted
  Hieracium albiflorum Hook. -- accepted -- white hawkweed, whiteflower hawkweed
  Hieracium gracile Hook. -- not accepted -- slender hawkweed
  Hieracium gracile var. gracile Hook. -- not accepted -- slender hawkweed
  Hieracium scouleri Hook. -- accepted -- houndstongue hawkweed, Scouler's woollyweed, woolyweed
  Hieracium scouleri var. scouleri Hook. -- not accepted -- Scouler's woollyweed
  Hieracium triste ssp. gracile (Hook.) Calder & Roy L. Taylor -- not accepted
  Hieracium triste var. gracile (Hook.) A. Gray -- not accepted
  Hierochloe magellanica (Desr.) Hook. f. -- not accepted
  Hierochloe magellanica Hook. f. -- not accepted
  Hierochloe redolens R. Br. ex Hook. f. -- not accepted
  Hierochloe redolens var. magellanica (Hook. f.) Macloskie -- not accepted
  Hodgsonia Hook. f. & Thomson -- accepted
  Hodgsonia heteroclita (Roxb.) Hook. f. & Thomson -- accepted -- Chinese lardplant
  Hoita strobilina (Hook. & Arn.) Rydb. -- accepted -- Loma prieta
  Hollia lyellii (Hook.) Sull. -- not accepted
  Holodiscus dumosus (Nutt. ex Hook.) A. Heller -- not accepted -- bush oceanspray, rockspirea
  Holographis virgata (Harv. ex Benth. & Hook. f.) T.F. Daniel -- accepted -- white devilbush
  Holozonia filipes (Hook. & Arn.) Greene -- accepted -- whitecrown
  Homalachne (Benth. & Hook.) Kuntze -- not accepted
  Homalothecium leskeoides (Hook.) Robins. -- not accepted
  Honckenya peploides ssp. major (Hook.) Hultén -- accepted -- seaside sandplant
  Honckenya peploides var. major (Hook.) Abrams -- not accepted
  Hoodia cactiformis (Hook.) Halda -- not accepted
  Hoodia currorii (Hook.) Decne. -- accepted
  Hoodia currorii ssp. currorii (Hook.) Decne. -- accepted
  Hookeria acutifolia Hook. & Grev. -- accepted -- sharpleaf hookeria moss
  Hopea micrantha Hook. f. -- accepted -- hopea
  Hordeum comosum var. pubiflorum (Hook. f.) Thell. -- not accepted
  Hordeum pubiflorum Hook. f. -- accepted
  Hordeum pubiflorum ssp. pubiflorum Hook. f. -- accepted
  Hordeum secalinum var. pubiflorum (Hook. f.) Hauman -- not accepted
  Horkelia congesta Douglas ex Hook. -- accepted -- Sierra horkelia
  Horkelia congesta ssp. congesta Douglas ex Hook. -- not accepted -- Sierra horkelia
  Horkelia congesta var. congesta Douglas ex Hook. -- accepted -- Sierra horkelia
  Horkelia fusca ssp. parviflora (Nutt. ex Hook. & Arn.) D.D. Keck -- not accepted -- smallflower horkelia
  Horkelia fusca var. parviflora (Nutt. ex Hook. & Arn.) Wawra -- accepted
  Horkelia gordonii Hook. -- not accepted
  Horkelia parviflora Nutt. ex Hook. & Arn. -- not accepted
  Hormidium pygmaeum (Hook.) Benth. & Hook. f. -- not accepted
  Hosackia pinnata (Hook.) Abrams -- accepted -- meadow bird's-foot trefoil
  Hosackia tomentosa Hook. & Arn. -- not accepted
  Hosackia tomentosa ssp. glabriuscula (Hook. & Arn.) Abrams -- not accepted
  Houstonia acerosa (A. Gray) Benth. & Hook. f. -- accepted -- needleleaf bluet
  Houstonia acerosa ssp. acerosa (A. Gray) A. Gray ex Benth. & Hook. f. -- not accepted -- needleleaf bluet
  Houstonia acerosa var. acerosa (A. Gray) A. Gray ex Benth. & Hook. f. -- accepted -- needleleaf bluet
  Houttea gardneri (Hook.) Decne. -- not accepted
  Houttea pardina (Hook.) Decne. -- not accepted
  Houttea tubiflora (Hook.) Heynh. -- not accepted
  Huperzia phyllantha (Hook. & Arn.) Holub -- accepted -- daggerleaf clubmoss
  Hyalocereus lemairei (Hook.) Britton & Rose -- not accepted
  Hygroamblystegium irriguum (Hook. & Wils.) Loeske -- not accepted
  Hygrobiella laxifolia (Hook.) Spruce -- accepted
  Hylocereus lemairei (Hook.) Britton & Rose -- not accepted
  Hylotelephium sieboldii (Sweet ex Hook.) H. Ohba -- accepted
  Hymenopappus filifolius Hook. -- accepted -- cutleaf, fine-leaf woollywhite, fineleaf hymenopappus
  Hymenopappus filifolius var. filifolius Hook. -- accepted -- fineleaf hymenopappus
  Hymenophyllum lanceolatum Hook. & Arn. -- accepted -- palaihinahina
  Hymenophyllum obtusum Hook. & Arn. -- accepted -- palailaulii
  Hymenophyllum polyanthos var. protrusum (Hook.) Farw. -- not accepted
  Hymenophyllum protrusum Hook. -- accepted
  Hymenophyton leptopodum (Hook.f. & Taylor) A. Evans -- accepted
  Hymenosporum flavum (Hook.) F. Muell. -- accepted
  Hymenoxys linearifolia Hook. -- not accepted
  Hymenoxys richardsonii (Hook.) Cockerell -- accepted -- Colorado rubberweed, pingue, pingue hymenoxys, pingue rubberweed
  Hymenoxys richardsonii var. richardsonii (Hook.) Cockerell -- accepted -- Colorado rubberweed, pingue hymenoxys, pingue rubberweed
  Hyophila involuta (Hook.) Jaeg. -- accepted -- hyophila moss
  Hypericum drummondii (Grev. & Hook.) Torr. & A. Gray -- accepted -- Drummond's St. Johnswort, nits and lice
  Hypericum ellipticum Hook. -- accepted -- pale St. Johnswort
  Hypericum formosum ssp. scouleri (Hook.) C.L. Hitchc. -- not accepted
  Hypericum formosum var. scouleri (Hook.) J.M. Coult. -- not accepted
  Hypericum scouleri Hook. -- accepted -- Scouler's St. Johnswort
  Hypericum scouleri ssp. scouleri Hook. -- not accepted -- Scouler's St. Johnswort
  Hypnum circinale Hook. -- accepted -- hypnum moss
  Hypnum robustum W.J. Hooker -- not accepted
  Hypochaeris brasiliensis (Less.) Benth. & Hook. ex Griseb. -- not accepted -- Brazilian catsear
  Hypochaeris brasiliensis var. tweediei (Hook. & Arn.) Baker -- not accepted
  Hypochaeris brasiliensis var. tweedyi (Hook. & Arn.) Baker -- not accepted -- Tweedy's catsear
  Hypochaeris tweediei Hook. & Arn. -- not accepted
  Hypochaeris tweedyi Hook. & Arn. -- not accepted
  Hypocyrta glabra Hook. -- not accepted
  Hypocyrta gracilis Hook. -- not accepted
  Hypocyrta leucostoma Hook. -- not accepted
  Hypocyrta villosa Hook. & Arn. -- not accepted
  Hypodermis R. Br. ex Hook. -- not accepted
  Hypoderris R. Br. ex Hook. -- accepted
  Hypolepis nigrescens Hook. -- accepted -- black beadfern
  Idahoa scapigera (Hook.) A. Nelson & J.F. Macbr. -- accepted -- flatpod, oldstem idahoa
  Ilex anomala Hook. & Arn. -- accepted -- Hawai'i holly
  Iliamna rivularis (Douglas ex Hook.) Greene -- accepted -- streambank globemallow, streambank wild hollyhock, streambank wildhollyhock
  Iliamna rivularis var. rivularis (Douglas ex Hook.) Greene -- accepted -- Peter's mountain mallow, streambank wild hollyhock
  Illicium verum Hook. f. -- accepted -- staranise tree
  Impatiens balfourii Hook. f. -- accepted -- Balfour's touch-me-not
  Impatiens sultani Hook. f. -- not accepted
  Impatiens walleriana Hook. f. -- accepted -- buzzy lizzy
  Indigofera atriceps Hook. f. -- accepted
  Ipomoea horsfalliae Hook. -- accepted -- Lady Doorly's morning-glory, Lady Doorly's morningglory
  Ipomopsis congesta (Hook.) V.E. Grant -- accepted -- ball-head skyrocket, ballhead gilia, ballhead ipomopsis, ballhead skyrocket
  Ipomopsis congesta ssp. congesta (Hook.) V.E. Grant -- accepted -- ball-head skyrocket, ballhead gilia, ballhead ipomopsis
  Iresine grandiflora Hook. -- not accepted
  Iresine herbstii Hook. -- accepted -- Herbst's bloodleaf
  Iresine leptoclada (Hook. f.) Henrickson & S.D. Sundb. -- accepted -- Texas shrub
  Ischaemum aureum (Hook. & Arn.) Hack. -- accepted -- golden duckbeakgrass
  Ischnochloa Hook. f. -- not accepted
  Isocoma menziesii (Hook. & Arn.) G.L. Nesom -- accepted -- Menzies' goldenbush
  Isocoma menziesii var. menziesii (Hook. & Arn.) G.L. Nesom -- accepted -- Menzies' goldenbush
  Isolepis carinata Hook. & Arn. ex Torr. -- accepted -- keeled bulrush
  Isoloma bogotense var. ocellatum (Hook.) Voss -- not accepted
  Isoloma hypocyrtiflorum (Hook. f.) Benth. -- not accepted
  Isoloma ocellatum (Hook.) Benth. ex Jacks. -- not accepted
  Isoloma pictum (Hook.) Decne. ex Planch. -- not accepted
  Isoloma pictum (Hook.) Regel -- not accepted
  Isoloma pictum var. minus-hirsuta (Hook.) Planch. -- not accepted
  Isoloma seemannii (Hook.) Benth. -- not accepted
  Isoloma triflorum (Hook.) Decne. -- not accepted
  Isonandra gutta Hook. -- not accepted
  Isopyrum occidentale Hook. & Arn. -- not accepted
  Isotachis humectata (Hook.f. & Taylor) Steph. -- accepted
  Isotachis intortifolia (Hook.f. & Taylor) Gottsche -- accepted
  Iva axillaris ssp. robustior (Hook.) Bassett -- not accepted
  Iva axillaris var. robustior Hook. -- not accepted
  Ivesia gordanii (Hook.) Torr. & A. Gray -- not accepted
  Ivesia gordonii (Hook.) Torr. & A. Gray -- accepted -- Gordon's ivesia
  Ivesia gordonii var. gordonii (Hook.) Torr. & A. Gray -- accepted -- Gordon's ivesia
  Ixora thwaitesii Hook. f. -- accepted -- white jungleflame
  Jacobinia candicans (Nees) Benth. & Hook. f. -- not accepted
  Jatropha podagrica Hook. -- accepted -- goutystalk nettlespurge
  Joinvillea plicata (Hook. f.) Newell & B.C. Stone -- accepted
  Jubula hutchinsiae (Hook.) Dumort. -- accepted
  Jubula hutchinsiae ssp. hutchinsiae (Hook.) Dumort. -- accepted
  Juncus effusus var. gracilis Hook. -- not accepted -- lamp rush
  Juncus ensifolius var. major Hook. -- not accepted
  Jungermannia albescens Hook. -- not accepted
  Jungermannia argentea Hook.f. & Taylor -- not accepted
  Jungermannia blasia Hook. -- not accepted
  Jungermannia clavigera Hook. -- not accepted
  Jungermannia cordifolia Hook. -- not accepted
  Jungermannia epiphylla var. furcigera Hook. -- not accepted
  Jungermannia epiphylla var. longifolia Hook. -- not accepted
  Jungermannia furcata var. elongata Hook. -- not accepted
  Jungermannia hibernica Hook. -- not accepted
  Jungermannia lyellii Hook. -- not accepted
  Jungermannia multifida var. sinuata Dicks. ex Hook. -- not accepted
  Jungermannia orcadensis Hook. -- not accepted
  Jungermannia pinguis var. angustior Hook. -- not accepted
  Jungermannia pinnatifolia Hook. -- not accepted
  Jungermannia polycantha Hook.f. & Taylor -- not accepted
  Jungermannia sphaerocarpa Hook. -- not accepted
  Jungermannia subtrifida Hook.f. & Taylor -- not accepted
  Jungermannia subtrifidum Hook.f. & Taylor -- not accepted
  Jungermannia woodsii Hook. -- not accepted
  Juniperus occidentalis Hook. -- accepted -- western juniper
  Juniperus occidentalis var. occidentalis Hook. -- accepted -- western juniper
  Juniperus wallichiana Hook. f. & Thomson ex Brandis -- accepted -- black juniper
  Jurtsevia richardsonii (Hook.) Á. Löve & D. Löve -- not accepted
  Kadua centranthoides Hook. & Arn. -- accepted
  Kaliphora Hook. f. -- accepted
  Kaliphora madagascariensis Hook. f. -- accepted
  Kallstroemia maxima (L.) Hook. & Arn. -- accepted -- big caltrop
  Kalmia microphylla (Hook.) A. Heller -- accepted -- alpine bog laurel, alpine laurel
  Kalmia microphylla var. microphylla (Hook.) A. Heller -- accepted -- alpine laurel, small-leaved kalmia, western alpine laurel
  Kalmia polifolia ssp. microphylla (Hook.) Calder & Roy L. Taylor -- not accepted
  Kalmia polifolia var. microphylla (Hook.) Hall -- not accepted
  Kalmia polifolia var. microphylla (Hook.) Rehder -- not accepted
  Klugia notoniana Hook. -- not accepted
  Kohleria inaequalis var. ocellata (Hook.) L.P. Kvist & L.E. Skog -- accepted
  Kohleria ocellata (Hook.) Fritsch -- not accepted
  Kohleria picta (Hook.) Hanst. -- not accepted
  Kohleria seemannii (Hook.) Hanst. -- not accepted
  Kohleria triflora (Hook.) Regel -- not accepted
  Kurzia hippurioides (Hook.f. & Taylor) Grolle -- accepted
  Kurzia hippurioides var. hippurioides (Hook.f. & Taylor) Grolle -- accepted
  Kurzia nemoides (Hook.f. & Taylor) Grolle -- accepted
  Lacanthis splendens (Bojer ex Hook.) Raf. -- not accepted
  Lacinaria punctata (Hook.) Kuntze -- not accepted
  Lagarostrobos franklinii (Hook. f.) Quinn -- accepted -- Huon pine
  Lantana camara var. mutabilis (Hook.) L.H. Bailey -- not accepted
  Lappago occidentalis Nees ex Hook. -- not accepted
  Larryleachia cactiformis (Hook.) Plowes -- accepted
  Lathyrus ochroleucus Hook. -- accepted -- cream pea, cream peavine, pale vetchling peavine
  Lathyrus pubescens Hook. & Arn. -- accepted
  Layia Hook. & Arn. ex DC. -- accepted -- tidytips
  Layia gaillardioides (Hook. & Arn.) DC. -- accepted -- woodland tidytips
  Layia glandulosa (Hook.) Hook. & Arn. -- accepted -- white tidytips, whitedaisy tidytips
  Layia glandulosa ssp. glandulosa (Hook.) Hook. & Arn. -- not accepted -- whitedaisy tidytips
  Layia heterotricha (DC.) Hook. & Arn. -- accepted -- paleyellow tidytips
  Layia hieracioides (DC.) Hook. & Arn. -- accepted -- tall tidytips
  Leiocolea bantriensis (Hook.) Jřrg. -- not accepted
  Leiomitra lanata (Hook.) R.M. Schust. -- accepted
  Lejeunea echinata (Hook.) Taylor ex Gottsche -- not accepted
  Lejeunea primordialis (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lembidium nutans (Hook.f. & Taylor) Mitt. -- accepted
  Lembidium nutans var. nutans (Hook.f. & Taylor) Mitt. -- accepted
  Lepanthes sanguinea Hook. -- accepted -- Jamaican babyboot orchid
  Lepicolea scolopendra (Hook.) Dumort. ex Trevis. -- accepted
  Lepidium latipes Hook. -- accepted -- San Diego pepperweed
  Lepidium latipes var. latipes Hook. -- not accepted -- San Diego pepperweed
  Lepidium smithii Hook. -- not accepted
  Lepidogyna menziesii (Hook.) R.M. Schust. -- accepted
  Lepidolaena clavigera (Hook.) Dumort. ex Trevis. -- accepted
  Lepidolaena palpebrifolia (Hook.) Dumort. ex Trevis. -- accepted
  Lepidolaena reticulata (Hook.f. & Taylor) Trevis. -- accepted
  Lepidozia cupressina ssp. pinnata (Hook.) Pócs -- accepted
  Lepidozia glaucophylla (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lepidozia laevifolia (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lepidozia laevifolia var. laevifolia (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lepidozia microphylla (Hook.) Lindenb. -- accepted
  Lepidozia pendulina (Hook.) Lindenb. -- accepted
  Lepidozia spinosissima (Hook.f. & Taylor) Mitt. -- accepted
  Leptodactylon Hook. & Arn. -- accepted -- prickly gilia, prickly phlox
  Leptodactylon californicum Hook. & Arn. -- accepted -- California prickly phlox
  Leptodactylon californicum ssp. californicum Hook. & Arn. -- accepted -- California prickly phlox
  Leptodactylon pungens ssp. hookeri (Douglas ex Hook.) Wherry -- not accepted
  Leptodactylon pungens var. hookeri (Douglas ex Hook.) Jeps. -- not accepted
  Leptoscyphus aequatus (Hook.f. & Taylor) Mitt. -- accepted
  Leptoscyphus cuneifolius (Hook.) Mitt. -- accepted
  Leptoscyphus cuneifolius ssp. cuneifolius (Hook.) Mitt. -- accepted
  Leptoscyphus horizontalis (Hook.) Kühnem. -- accepted
  Leptoscyphus physanthus (Hook.f. & Taylor) J.J. Engel -- accepted
  Leptosiphon rosaceus (Hook. f.) Battaglia -- accepted -- rose linanthus
  Lepturus filiformis var. incurvatus (L.) Hook. f. -- not accepted
  Lespedeza striata (Thunb.) Hook. & Arn. -- not accepted
  Lesquerella gracilis (Hook.) S. Watson -- not accepted -- lax bladderpod, spreading bladderpod
  Lesquerella gracilis ssp. gracilis (Hook.) S. Watson -- not accepted -- spreading bladderpod
  Lesquerella grandiflora (Hook.) S. Watson -- not accepted -- bigflower bladderpod
  Lesquerella lasiocarpa (Hook. ex A. Gray) S. Watson -- not accepted -- roughpod bladderpod
  Lesquerella lasiocarpa ssp. lasiocarpa (Hook. ex A. Gray) S. Watson -- not accepted -- roughpod bladderpod
  Lesquerella lasiocarpa var. lasiocarpa (Hook. ex A. Gray) S. Watson -- not accepted -- roughpod bladderpod
  Lessingia filaginifolia (Hook. & Arn.) M.A. Lane -- not accepted
  Lessingia filaginifolia var. filaginifolia (Hook. & Arn.) M.A. Lane -- not accepted
  Leuchtenbergia Hook. -- accepted
  Leuchtenbergia principis Hook. -- accepted
  Leucolepis menziesii (Hook.) Steere in L. Koch -- not accepted
  Leucophysalis grandiflora (Hook.) Rydb. -- accepted -- large false groundcherry
  Liatris punctata Hook. -- accepted -- dotted blazing star, dotted gayfeather
  Liatris punctata var. punctata Hook. -- accepted -- densespike blazing star, dotted blazing star, dotted gayfeather
  Ligeria concinna (Hook. f.) Hanst. -- not accepted
  Ligusticum verticillatum (Hook.) J.M. Coult. & Rose ex Rose -- accepted -- northern licorice-root
  Lilaeopsis attenuata auct. non (Hook. & Arn.) Fernald -- not accepted
  Lilium canadense var. parviflorum Hook. -- not accepted
  Linanthus californicus (Hook. & Arn.) J.M. Porter & L.A. Johnson -- not accepted
  Linanthus parviflorus var. rosaceus Hook. f. -- not accepted
  Linaria maroccana Hook. f. -- accepted -- Moroccan toadflax
  Lindsaea repens var. macraeana (Hook. & Arn.) Mett. ex Kuhn -- accepted -- creeping necklace fern
  Lindsaea walkerae Hook. -- accepted
  Linum berlandieri Hook. -- accepted -- Berlandier's yellow flax
  Linum berlandieri var. berlandieri Hook. -- accepted -- Berlandier's yellow flax
  Linum rigidum var. berlandieri (Hook.) Torr. & A. Gray -- not accepted
  Lipochaeta lobata var. hastulata (Hook. & Arn.) Sherff -- not accepted
  Lipochaeta succulenta (Hook. & Arn.) DC. -- accepted -- seaside nehe
  Lithocarpus densiflorus (Hook. & Arn.) Rehder -- accepted -- tanoak
  Lithocarpus densiflorus var. densiflorus (Hook. & Arn.) Rehder -- accepted -- tanoak
  Lithophragma heterophyllum (Hook. & Arn.) Hook. & Arn. -- accepted -- hillside woodland-star
  Lithophragma parviflorum (Hook.) Nutt. -- accepted -- smallflower woodland-star
  Lithophragma parviflorum var. parviflorum (Hook.) Nutt. -- not accepted -- smallflower woodland-star
  Lithrea Miers ex Hook. & Arn. -- accepted
  Lobatiriccardia alterniloba (Hook.f. & Taylor) Furuki -- accepted
  Lobatiriccardia alterniloba var. alterniloba (Hook.f. & Taylor) Furuki -- accepted
  Lobivia cinnabarina (Hook.) Britton & Rose -- not accepted
  Lobivia pentlandii (Hook.) Britton & Rose -- not accepted
  Loeflingia squarrosa var. texana (Hook.) Dorn -- not accepted
  Loeflingia texana Hook. -- not accepted
  Logfia filaginoides (Hook. & Arn.) Morefield -- accepted -- California cottonrose
  Lomatium caruifolium (Hook. & Arn.) J.M. Coult. & Rose -- accepted -- alkali desertparsley
  Lomatium caruifolium var. caruifolium (Hook. & Arn.) J.M. Coult. & Rose -- accepted -- alkali desertparsley
  Lomatium farinosum (Geyer ex Hook.) J.M. Coult. & Rose -- accepted -- northern biscuitroot
  Lomatium farinosum var. farinosum (Geyer ex Hook.) J.M. Coult. & Rose -- accepted -- northern biscuitroot
  Lomatium parvifolium (Hook. & Arn.) Jeps. -- accepted -- coastal biscuitroot
  Lomatium simplex var. leptophyllum (Hook.) Mathias -- accepted -- slenderleaf lomatium
  Lonicera oblongifolia (Goldie) Hook. -- accepted -- swamp fly honeysuckle
  Lonicera oblongifolia var. oblongifolia (Goldie) Hook. -- not accepted -- swamp fly honeysuckle
  Lonicera subspicata Hook. & Arn. -- accepted -- southern honeysuckle
  Lonicera subspicata var. subspicata Hook. & Arn. -- accepted -- southern honeysuckle
  Lophocolea bispinosa (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lophocolea humifusa (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lophocolea humistrata (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lophocolea lenta (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lophocolea leptantha (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lophocolea perpusilla (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lophocolea sabuletorum (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lophocolea subemarginata Hook.f. & Taylor -- accepted
  Lophocolea subviridis (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lophocolea textilis (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Lopholejeunea plicatiscypha (Hook.f. & Taylor) Steph. -- accepted
  Lophopyxis Hook. -- accepted
  Lophopyxis maingayi Hook. f. -- accepted
  Lophozia bantriensis (Hook.) Steph. -- not accepted
  Lophozia capitata (Hook.) Macoun -- not accepted
  Lopidium Hook. f. & Wilson -- accepted
  Lotus pinnatus Hook. -- not accepted -- meadow bird's-foot trefoil
  Lotus unifoliolatus (Hook.) Benth. -- not accepted -- American bird's-foot trefoil, American bird's-foot-trefoil, American birdsfoot trefoil
  Lotus unifoliolatus var. unifoliolatus (Hook.) Benth. -- not accepted -- American bird's-foot trefoil, American bird's-foot-trefoil, prairie trefoil, Spanish clover
  Luculia pinceana Hook. -- accepted
  Ludwigia grandiflora ssp. hexapetala (Hook. & Arn.) G.L. Nesom & Kartesz -- not accepted
  Ludwigia hexapetala (Hook. & Arn.) Zardini, H.Y. Gu & P.H. Raven -- accepted
  Lunania Hook. -- accepted
  Lupinus argenteus ssp. parviflorus (Nutt. ex Hook. & Arn.) L.Ll. Phillips -- not accepted
  Lupinus argenteus var. parviflorus (Nutt. ex Hook. & Arn.) C.L. Hitchc. -- not accepted
  Lupinus foliosus (Torr. & A. Gray) Nutt. ex Hook. -- not accepted
  Lupinus minimus Douglas ex Hook. -- accepted -- Kettle Falls lupine
  Lupinus nootkatensis var. glaber Hook. -- not accepted
  Lupinus parviflorus Nutt. ex Hook. & Arn. -- accepted -- lodgepole lupine
  Lupinus parviflorus ssp. parviflorus Nutt. ex Hook. & Arn. -- accepted -- lodgepole lupine
  Lupinus sabinei Douglas ex Hook. -- not accepted
  Lupinus sabinii Douglas ex Hook. -- not accepted
  Lupinus sericeus ssp. sabinei (Douglas ex Hook.) L.Ll. Phillips -- not accepted
  Lupinus sericeus ssp. sabinii (Douglas ex Hook.) L.Ll. Phillips -- not accepted
  Lupinus subcarnosus Hook. -- accepted -- Texas bluebonnet
  Lupinus sulphureus Douglas ex Hook. -- accepted -- sulphur lupine
  Lupinus texensis Hook. -- accepted -- Texas bluebonnet, Texas lupine
  Lupinus truncatus Nutt. ex Hook. & Arn. -- accepted -- collared annual lupine
  Lychnis drummondii (Hook.) S. Watson -- not accepted
  Lycopodium cernuum var. curvatum (Sw.) Hook. & Grev. -- not accepted
  Lycopodium clavatum ssp. monostachyon (Hook. & Grev.) Selander -- not accepted
  Lycopodium clavatum var. monostachyon Hook. & Grev. -- not accepted
  Lycopodium clavatum var. tristachyum (Pursh) Hook. -- not accepted
  Lycopodium phyllanthum Hook. & Arn. -- not accepted
  Lygodesma juncea (Pursh) D. Don ex Hook. -- not accepted
  Lygodesmia juncea (Pursh) D. Don ex Hook. -- accepted -- rush skeleton-plant, rush skeletonplant, rush skeletonweed, skeletonplant, skeletonweed
  Lyrocarpa Hook. & Harv. -- accepted -- lyrepod
  Lyrocarpa coulteri Hook. & Harv. -- accepted -- Coulter lyrefruit, Coulter's lyrepod
  Lyrocarpa coulteri var. coulteri Hook. & Harv. -- not accepted -- Coulter lyrepod, Coulter's lyrepod
  Lysimachia hillebrandii Hook. f. ex A. Gray -- accepted -- pua-hekili
  Lysimachia radicans Hook. -- accepted -- trailing yellow loosestrife
  Machaeranthera pinnatifida (Hook.) Shinners -- not accepted -- cutleaf goldenweed, lacy tansy-aster, lacy tansyaster, pinnate machaeranthera, spiny goldenweed
  Machaeranthera pinnatifida ssp. pinnatifida (Hook.) Shinners -- not accepted -- lacy tansy-aster, lacy tansyaster
  Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida (Hook.) Shinners -- not accepted -- lacy tansy-aster, lacy tansyaster, spiny goldenweed
  Machaeranthera pinnatifida var. pinnatifida (Hook.) Shinners -- not accepted -- lacy tansyaster
  Macropidia fuliginosa (Hook.) Druce -- accepted
  Macrozamia corallipes Hook. f. -- not accepted
  Madia glomerata Hook. -- accepted -- cluster tarweed, mountain tarplant, mountain tarweed
  Manfreda maculosa (Hook.) Rose -- accepted -- Amole de culebra, spice lily
  Manihot grahamii Hook. -- accepted -- Graham's manihot
  Marchesinia mackaii (Hook.) Gray -- accepted
  Marsdenia maculata Hook. -- not accepted
  Marsilea polycarpa Hook. & Grev. -- accepted -- Guayanan waterclover
  Marsilea vestita Hook. & Grev. -- accepted -- hairy pepperwort, hairy waterclover, water clover
  Marsilea vestita ssp. vestita Hook. & Grev. -- not accepted -- hairy pepperwort, hairy waterclover
  Mastigolejeunea auriculata (Wilson & Hook.) Steph. -- not accepted
  Mastigophora flagellifera (Hook.) Steph. -- not accepted
  Mastigophora woodsii (Hook.) Nees -- accepted
  Matricaria grandiflora (Hook.) Britton -- not accepted
  Matricaria maritima var. nana (Hook.) B. Boivin -- not accepted
  Mecranium Hook. f. -- accepted
  Megaceros leptohymenius (Hook. f. & Taylor) Steph. -- accepted
  Melandrium drummondii (Hook.) Hultén -- not accepted
  Melicope sandwicensis (Hook. & Arn.) T.G. Hartley & B.C. Stone -- accepted -- Mt. Kaala melicope
  Melocactus depressus Hook. -- not accepted
  Menodora decemfida (Gillies ex Hook. & Arn.) A. Gray -- accepted -- tenfinger menodora
  Mentha glabrior (Hook.) Rydb. -- not accepted
  Mentzelia albicaulis (Douglas ex Hook.) Douglas ex Torr. & A. Gray -- accepted -- white blazingstar, white-stemmed evening-star, whitestem blazingstar, whitestem stickleaf
  Mentzelia albicaulis var. albicaulis (Hook.) Torr. & A. Gray -- not accepted -- whitestem blazingstar
  Mentzelia laevicaulis (Hook.) Torr. & A. Gray -- accepted -- blazingstar mentzelia, smoothstem blazingstar
  Mentzelia laevicaulis var. laevicaulis (Hook.) Torr. & A. Gray -- accepted -- smoothstem blazingstar
  Mentzelia laevicaulis var. parviflora (Douglas ex Hook.) C.L. Hitchc. -- accepted -- smoothstem blazingstar
  Mentzelia micrantha (Hook. & Arn.) Torr. & A. Gray -- accepted -- San Luis blazingstar
  Menziesia glanduliflora Hook. -- not accepted
  Merostachys capitata Hook. -- not accepted
  Merostachys capitata var. capitata Hook. -- not accepted
  Mesadenia reniformis (Hook.) Raf. -- not accepted
  Mesoptychia bantriensis (Hook.) L. Söderstr. & Vána -- accepted
  Mesoptychia bantriensis ssp. bantriensis (Hook.) L. Söderstr. & Vána -- accepted
  Metaneckera menziesii (Hook. in Drumm.) Steere -- accepted -- Menzies' metaneckera moss
  Metrosideros macropus Hook. & Arn. -- accepted -- 'ohi'a
  Micranthes integrifolia (Hook.) Small -- accepted -- wholeleaf saxifrage
  Micranthes reflexa (Hook.) Small -- accepted -- reflexed saxifrage
  Microlejeunea latitans (Hook.f. & Taylor) Heinrichs, Schäf.-Verw., Pócs & S. Dong -- accepted
  Microseris laciniata (Hook.) Sch. Bip. -- accepted -- cutleaf silverpuffs
  Microseris laciniata ssp. laciniata (Hook.) Sch. Bip. -- accepted -- cutleaf silverpuffs
  Microseris nutans (Hook.) Sch. Bip. -- accepted -- nodding microseris, nodding silverpuffs
  Microseris nutans ssp. nutans (Hook.) Sch. Bip. -- not accepted -- nodding silverpuffs
  Microsteris gracilis (Hook.) Greene -- accepted -- slender phlox
  Microsteris gracilis var. gracilis (Hook.) Greene -- accepted -- slender phlox
  Microsteris gracilis var. humilior (Hook.) Cronquist -- accepted -- slender phlox
  Mielichhoferia elongata (Hoppe & Hornsch. ex Hook.) Nees & Hornsch. in Nees et al. -- not accepted
  Mielichhoferia macrocarpa (Hook. in Drumm.) Bruch & Schimp. ex Jaeg. -- accepted -- waterfall copper moss
  Mielichhoferia mielichhoferi (Funck Ex Hook.) Loeske -- accepted
  Mielichhoferia mielichhoferiana (Funck in Hook.) Loeske -- accepted -- Mielichhof's copper moss
  Mielichhoferia mielichhoferiana var. elongata (Hoppe & Hornsch. ex Hook.) Wijk & Marg. -- accepted -- Mielichhofer's copper moss
  Mielichhoferia mielichhoferiana var. mielichhoferiana (Funck in Hook.) Loeske -- accepted -- Mielichhofer's copper moss
  Miltitzia lutea (Hook. & Arn.) A. DC. -- not accepted
  Mimulus guttatus ssp. scouleri (Hook.) Pennell -- not accepted
  Mimulus luteus var. cupreus (hort. ex Dombrain) Hook. -- not accepted
  Mimulus nanus Hook. & Arn. -- accepted -- dwarf purple monkeyflower
  Mimulus nanus ssp. nanus Hook. & Arn. -- accepted -- dwarf purple monkeyflower
  Mimulus nanus var. subuniflorus Hook. & Arn. -- not accepted
  Mimulus scouleri Hook. -- not accepted
  Mimulus subuniflorus (Hook. & Arn.) Piper -- not accepted
  Mimulus subuniflorus (Hook. & Arn.) Jeps. -- not accepted
  Mirabilis coccinea (Torr.) Benth. & Hook. f. -- accepted -- red four-o'clock, scarlet four o'clock, scarlet four-o'clock
  Mitella pentandra Hook. -- accepted -- fivestamen miterwort
  Mnium menziesii Hook. -- not accepted
  Moehringia macrophylla (Hook.) Fenzl -- accepted -- large-leaved sandwort, largeleaf sandwort
  Moehringia macrophyllum (Hook.) Fenzl -- not accepted
  Moerckia hibernica (Hook.) Gottsche -- accepted
  Molendoa hornschuchiana (Hook.) Lindb. ex Limpr. -- accepted -- Hornschuch's molendoa moss
  Monoclea Hook. -- accepted
  Monoclea adglutinata Hook. f. & Taylor -- not accepted
  Monoclea crispata Hook. -- not accepted
  Monoclea forsteri Hook. -- accepted
  Monoclea leptohymenia Hook. f. & Taylor -- not accepted
  Montia linearis (Douglas ex Hook.) Greene -- accepted -- narrowleaf Indianlettuce, narrowleaf minerslettuce
  Montia parviflora (Douglas ex Hook.) Howell -- not accepted
  Montia perfoliata var. parviflora (Douglas ex Hook.) Jeps. -- not accepted
  Montiastrum lineare (Douglas ex Hook.) Rydb. -- not accepted
  Morrenia odorata (Hook. & Arn.) Lindl. -- accepted -- latexplant
  Muehlenbeckia axillaris (Hook. f.) Walp. -- accepted -- sprawling wirevine
  Muehlenbeckia axillaris auct. non (Hook. f.) Walp. -- not accepted
  Muhlenbergia cuspidata (Torr. ex Hook.) Rydb. -- accepted -- plains muhly
  Muhlenbergia rariflora Hook. f. -- not accepted
  Mundulea barclayi (Telf. ex Hook.) R. Viguier ex Du Puy & Labat -- accepted
  Mylia anomala (Hook.) Gray -- accepted
  Mylia cuneifolia (Hook.) Gray -- not accepted
  Mylia taylorii (Hook.) Gray -- accepted
  Myosotidium Hook. -- accepted -- giant forget-me-not
  Myosotis azorica H.C. Watson ex Hook. -- accepted -- Azores forget-me-not
  Myriogramme livida (Hooker and Harvey) Kylin -- accepted
  Myriophyllum proserpinacoides Gillies ex Hook. & Arn. -- not accepted
  Myzorrhiza pinorum (Geyer ex Hook.) Rydb. -- not accepted
  Nabalus albus (L.) Hook. -- not accepted
  Nabalus altissimus (L.) Hook. -- not accepted
  Nabalus serpentarius (Pursh) Hook. -- not accepted
  Naegelia amabilis hort. ex Hook. -- not accepted
  Naegelia multiflora (Martens & Galeotti) Hook. -- not accepted
  Nama aretioides (Hook. & Arn.) Brand -- accepted -- ground nama, purple nama
  Nama aretioides var. aretioides (Hook. & Arn.) Brand -- accepted -- ground nama
  Napeanthus primulinus (H. Karst.) Benth. & Hook. f. ex Jacks. -- accepted
  Napeanthus subacaulis (Griseb.) Benth. & Hook. f. ex Kuntze -- accepted
  Napeanthus subacaulis var. subacaulis (Griseb.) Benth. & Hook. f. ex Kuntze -- accepted
  Nardia compressa (Hook.) Gray -- accepted
  Nasturtium curvisiliqua (Hook.) Nutt. ex Torr. & A. Gray -- not accepted
  Nautilocalyx bicolor (Hook.) Wiehler -- accepted
  Nautilocalyx lynchii (Hook. f.) Sprague -- accepted
  Nautilocalyx pictus (Hook.) Sprague -- accepted
  Navarretia atractyloides (Benth.) Hook. & Arn. -- not accepted
  Navarretia atractyloides (Benth.) Hook. & Arn. -- accepted -- hollyleaf pincushionplant
  Navarretia cotulifolia (Benth.) Hook. & Arn. -- accepted -- cotulaleaf pincushionplant
  Navarretia intertexta (Benth.) Hook. -- accepted -- needle-leaf pincushion-plant, needleleaf navarretia
  Navarretia intertexta ssp. intertexta (Benth.) Hook. -- accepted -- needleleaf navarretia
  Navarretia pubescens (Benth.) Hook. & Arn. -- accepted -- downy pincushionplant
  Navarretia squarrosa (Eschsch.) Hook. & Arn. -- accepted -- skunkbush
  Neanotis foetida (Hook. f.) W.H. Lewis -- not accepted
  Neckera californica W.J. Hooker & Arnott -- not accepted
  Neckera douglasii Hook. -- accepted -- Douglas' neckera moss
  Neckera menziesii Hook. in Drumm. -- not accepted
  Neckeradelphus menziesii (Hook. in Drumm.) Steere -- not accepted
  Neea buxifolia (Hook. f.) Heimerl -- accepted -- saltwood
  Nemexia lasioneura (Hook.) Rydb. -- not accepted
  Nemophila menziesii Hook. & Arn. -- accepted -- baby blue eyes, baby blue-eyes
  Nemophila menziesii var. menziesii Hook. & Arn. -- accepted -- baby blue eyes
  Neogaerrhinum strictum (Hook. & Arn.) Rothm. -- accepted -- Kellogg's snapdragon
  Neolepidozia patentissima (Hook.f. & Taylor) E.D. Cooper -- accepted
  Neolepidozia patentissima var. patentissima (Hook.f. & Taylor) E.D. Cooper -- accepted
  Neolepidozia tetrapila (Hook.f. & Taylor) E.D. Cooper -- accepted
  Neolepidozia tetrapila var. tetrapila (Hook.f. & Taylor) E.D. Cooper -- accepted
  Nepenthes bicalcarata Hook. f. -- accepted
  Nepenthes burbidgeae Hook. f. ex Burb. -- accepted
  Nepenthes edwardsiana Low ex Hook. f. -- accepted
  Nepenthes hirsuta Hook. f. -- accepted
  Nepenthes khasiana Hook. f. -- accepted
  Nepenthes lowii Hook. f. -- accepted
  Nepenthes northiana Hook. f. -- accepted
  Nepenthes rajah Hook. f. -- accepted
  Nepenthes tentaculata Hook. f. -- accepted
  Nepenthes veitchii Hook. f. -- accepted
  Nepenthes vieillardii Hook. f. -- accepted
  Nepenthes villosa Hook. f. -- accepted
  Nephelolejeunea nudipes (Hook.f. & Taylor) L. Söderstr. & A. Hagborg -- accepted
  Nephrodium funestum (Kunze) Hook. -- not accepted
  Nephrophyllidium crista-galli (Menzies ex Hook.) Gilg -- accepted -- deer-cabbage, deercabbage
  Neyraudia Hook. f. -- accepted -- neyraudia
  Neyraudia madagascariensis var. zollingeri (Büse) Hook. f. -- not accepted
  Nicotiana acuminata (Graham) Hook. -- accepted -- manyflower tobacco
  Nicotiana acuminata var. acuminata (Graham) Hook. -- accepted -- manyflower tobacco
  Niphaea albo-lineata Hook. -- not accepted
  Nitophyllum lividum Hooker and Harvey -- not accepted
  Noteroclada Taylor ex Hook.f. & Wilson -- accepted
  Notholaena candida (M. Martens & Galeotti) Hook. -- accepted
  Notholaena integerrima (Hook.) Hevly -- not accepted
  Notholaena sinuata var. integerrima Hook. -- not accepted
  Notocactus joadii (Hook. f.) Herter -- not accepted
  Notopleura (Benth. & Hook. f.) Bremek. -- accepted
  Nummularia radicans (Hook.) Kuntze -- not accepted
  Nuttallia cerasiformis Torr. & A. Gray ex Hook. & Arn. -- not accepted
  Nuttallia laevicaulis (Hook.) Greene -- not accepted
  Nymphaea elegans Hook. -- accepted -- tropical royalblue waterlily
  Odontoschisma francisci (Hook.) L. Söderstr. & Vána -- accepted
  Oemleria cerasiformis (Torr. & A. Gray ex Hook. & Arn.) J.W. Landon -- accepted -- Indian plum
  Oenothera alyssoides Hook. & Arn. -- not accepted
  Oenothera bistorta var. veitchiana Hook. -- not accepted
  Oenothera boothii ssp. alyssoides (Hook. & Arn.) Munz -- not accepted
  Oenothera boothii ssp. decorticans (Hook. & Arn.) Munz -- not accepted
  Oenothera caespitosa ssp. marginata (Nutt. ex Hook. & Arn.) Munz -- not accepted -- tufted evening primrose, tufted evening-primrose
  Oenothera caespitosa var. marginata (Nutt. ex Hook. & Arn.) Munz -- not accepted
  Oenothera cespitosa ssp. marginata (Nutt. ex Hook. & Arn.) Munz -- accepted -- tufted evening primrose, tufted eveningprimrose
  Oenothera cespitosa var. marginata (Nutt. ex Hook. & Arn.) Munz -- not accepted
  Oenothera decorticans (Hook. & Arn.) Greene -- not accepted
  Oenothera drummondii Hook. -- accepted -- beach evening primrose, beach evening-primrose, beach eveningprimrose
  Oenothera drummondii ssp. drummondii Hook. -- accepted -- beach evening primrose
  Oenothera fruticosa var. vera Hook. -- not accepted
  Oenothera graciliflora Hook. & Arn. -- not accepted
  Oldenlandia salzmannii (DC.) Benth. & Hook. f. ex B.D. Jacks. -- accepted -- Salzmann's mille graines
  Olyra concinna Hook. f. -- not accepted
  Ophioglossum ellipticum Hook. & Grev. -- not accepted
  Ophioglossum petiolatum Hook. -- accepted -- longstem adder's-tongue, longstem adderstongue, stalked adder's-tongue
  Oplotheca gracilis Hook. -- not accepted
  Oreocharis primuloides (Miq.) Benth. & Hook. f. ex C.B. Clarke -- accepted
  Orobanche pinorum Geyer ex Hook. -- accepted -- conifer broomrape
  Orothamnus Pappe ex Hook. -- accepted
  Orothamnus zeyheri Pappe ex Hook. -- accepted
  Ortachne rariflora (Hook. f.) Hughes -- accepted
  Orthocarpus tolmiei Hook. & Arn. -- accepted -- Tolmie's owl's-clover
  Orthocarpus tolmiei ssp. tolmiei Hook. & Arn. -- accepted -- Tolmie's owl's-clover
  Orthodontium pellucens (Hook.) Bruch & Schimp. in B.S.G. -- accepted -- orthodontium moss
  Ortholoma minor (Hook.) Wiehler -- not accepted
  Ortholoma repens (Hook.) Wiehler -- not accepted
  Orthotrichum lyellii Hook. & Tayl. -- accepted -- Lyell's orthotrichum moss
  Orthotrichum speciosum var. elegans (Schwaegr. ex Hook. & Grev.) Warnst. -- accepted -- elegant lanceolateleaf rock moss
  Oryzopsis miliacea (L.) Benth. & Hook. ex Asch. & Schweinf. -- not accepted
  Osmanthus americanus (L.) Benth. & Hook. f. ex A. Gray -- accepted -- devilwood
  Osmanthus americanus var. americanus (L.) Benth. & Hook. f. ex A. Gray -- accepted -- American devilwood, devilwood
  Osmaronia cerasiformis (Torr. & A. Gray ex Hook. & Arn.) Greene -- not accepted
  Osmorhiza chilensis Hook. & Arn. -- not accepted
  Oxalis laxa Hook. & Arn. -- not accepted
  Oxalis trilliifolia Hook. -- accepted -- threeleaf woodsorrel
  Oxystegus tenuirostris (Hook. & Tayl.) A.J.E. Sm. -- accepted -- oxystegus moss
  Oxytropis campestris ssp. melanocephala (Hook.) A.E. Porsild -- not accepted
  Oxytropis campestris var. glabrata Hook. -- not accepted
  Oxytropis campestris var. melanocephala Hook. -- not accepted
  Oxytropis campestris var. minor (Hook.) S.L. Welsh -- accepted -- field locoweed
  Oxytropis campestris var. spicata Hook. -- accepted -- field locoweed
  Oxytropis deflexa ssp. foliolosa (Hook.) Cody -- not accepted
  Oxytropis deflexa var. foliolosa (Hook.) Barneby -- accepted -- nodding locoweed, pendant-pod crazyweed, pendantpod locoweed
  Oxytropis foliolosa Hook. -- not accepted
  Oxytropis glabrata (Hook.) A. Nelson -- not accepted
  Oxytropis maydelliana ssp. melanocephala (Hook.) A.E. Porsild -- not accepted
  Oxytropis nigrescens var. uniflora (Hook.) Barneby -- accepted -- one-flowered blackish locoweed, oneflower blackish locoweed
  Oxytropis podocarpa var. inflata (Hook.) B. Boivin -- not accepted
  Oxytropis richardsonii (Hook.) K. Schum. -- not accepted
  Oxytropis sericea ssp. spicata (Hook.) Cody -- not accepted
  Oxytropis sericea var. spicata (Hook.) Barneby -- not accepted -- Rocky Mountain locoweed
  Oxytropis spicata (Hook.) Standl. -- not accepted
  Oxytropis splendens Douglas ex Hook. -- accepted -- showy crazyweed, showy locoweed, showy pointvetch
  Oxytropis splendens var. richardsonii Hook. -- not accepted
  Oxytropis splendens var. vestita Hook. -- not accepted
  Oxytropis uralensis var. subsucculenta Hook. -- not accepted
  Oxytropis viscida var. subsucculenta (Hook.) Barneby -- not accepted
  Pachyglossa austrigena (Hook.f. & Taylor) L. Söderstr. -- accepted
  Pachyglossa austrigena ssp. austrigena (Hook.f. & Taylor) L. Söderstr. -- accepted
  Pachyglossa otiphylla (Hook.f. & Taylor) Vána -- accepted
  Pachyglossa tenacifolia (Hook.f. & Taylor) Herzog & Grolle -- accepted
  Packera cana (Hook.) W.A. Weber & Á. Löve -- accepted -- woolly groundsel
  Paeonia brownii Douglas ex Hook. -- accepted -- Brown's peony
  Palamocladium leskeoides (Hook.) Britt. -- accepted -- palamocladium moss
  Palaquium gutta (Hook.) Baill. -- accepted -- gutta percha
  Pallavicinia flotoviana var. hibernica (Hook.) Lindb. -- not accepted
  Pallavicinia lyellii (Hook.) Carruth. -- accepted
  Pallavicinia xiphoides (Hook.f. & Taylor) Trevis. -- accepted
  Pallavicinius hibernicus (Hook.) Gray -- not accepted
  Panicularia magellanica (Hook. f.) Kuntze -- not accepted
  Panicularia magellanica (Hook. f.) Macloskie -- not accepted
  Panicum beecheyi Hook. & Arn. -- accepted -- rock panicgrass
  Panicum nephelophilum var. tenuifolium (Hook. & Arn.) Hillebr. -- not accepted
  Panicum tenuifolium Hook. & Arn. -- accepted -- parkland panicgrass
  Paradrymonia erythropus (Hook. f.) Wiehler -- accepted
  Paradrymonia maculata (Hook. f.) Wiehler -- accepted
  Paradrymonia picta (Hook.) Hanst. -- not accepted
  Paraschistochila pinnatifolia (Hook) R.M. Schust. -- not accepted
  Parathesis (A. DC.) Hook. f. -- accepted
  Parathesis crenulata (Vent.) Hook. f. ex Hemsl. -- accepted -- scratchthroat
  Parkinsonia praecox (Ruiz & Pav. ex Hook.) J. Hawkins -- accepted
  Parrya platycarpa Hook. f. & Thomson -- not accepted
  Paspalum penicillatum Hook. f. -- accepted
  Paspalum sanguinale var. ciliare (Retz.) Hook. f. -- not accepted
  Paspalum sanguinale var. pruriens (Fisch. ex Trin.) Hook. f. -- not accepted
  Paspalum ternatum (Hochst. ex A. Rich.) Hook. f. -- not accepted
  Paysonia grandiflora (Hook.) O'Kane & Al-Shehbaz -- accepted -- bigflower bladderpod
  Paysonia lasiocarpa (Hook. ex A. Gray) O'Kane & Al-Shehbaz -- accepted -- roughpod bladderpod
  Paysonia lasiocarpa ssp. lasiocarpa (Hook. ex A. Gray) O'Kane & Al-Shehbaz -- accepted -- roughpod bladderpod
  Pearcea hypocyrtiflora (Hook. f.) Regel -- accepted
  Pectiantia pentandra (Hook.) Rydb. -- not accepted
  Pectocarya linearis var. penicillata (Hook. & Arn.) M.E. Jones -- not accepted
  Pectocarya penicillata (Hook. & Arn.) A. DC. -- accepted -- shortleaf combseed, sleeping combseed, winged combseed
  Pedicularis densiflora Benth. ex Hook. -- accepted -- Indian warrior
  Pedicularis densiflora ssp. densiflora Benth. ex Hook. -- not accepted -- Indian warrior
  Pelea sandwicensis (Hook. & Arn.) A. Gray -- not accepted
  Pellaea alabamensis (Buckley) Baker ex Hook. -- not accepted
  Pellaea bridgesii Hook. -- accepted -- Bridges' cliffbrake
  Pellaea decomposita (M. Martens & Galeotti) Hook. -- not accepted
  Pellaea decompositus (M. Martens & Galeotti) Hook. -- not accepted
  Pellaea densa (Brack.) Hook. -- not accepted
  Pellaea longimucronata auct. non Hook. -- not accepted
  Pellaea longimucronata Hook. -- not accepted
  Pellaea ternifolia var. wrightiana (Hook.) A.F. Tryon -- not accepted
  Pellaea wrightiana Hook. -- accepted -- Wright's cliffbrake
  Pennisetum exaltatum (Andersson) Hook. f. & B.D. Jacks. -- not accepted
  Penstemon baccharifolius Hook. -- accepted -- baccharisleaf beardtongue
  Penstemon cyananthus Hook. -- accepted -- Wasatch beardtongue
  Penstemon cyananthus var. cyananthus Hook. -- accepted -- Wasatch beardtongue
  Penstemon gairdneri Hook. -- accepted -- Gairdner's beardtongue
  Penstemon gairdneri var. gairdneri Hook. -- accepted -- Gairdner's beardtongue
  Penstemon labrosus (A. Gray) Mast. ex Hook. f. -- accepted -- San Gabriel beardtongue
  Penstemon laricifolius Hook. & Arn. -- accepted -- larchleaf beardtongue
  Penstemon laricifolius ssp. laricifolius Hook. & Arn. -- not accepted -- larchleaf beardtongue
  Penstemon laricifolius var. laricifolius Hook. & Arn. -- accepted -- larchleaf beardtongue
  Penstemon menziesii Hook. -- not accepted
  Penstemon murrayanus Hook. -- accepted -- scarlet beardtongue
  Penstemon ovatus Douglas ex Hook. -- accepted -- eggleaf beardtongue
  Penstemon procerus ssp. tolmiei (Hook.) D.D. Keck -- not accepted
  Penstemon procerus var. tolmiei (Hook.) Cronquist -- accepted -- Tolmie's penstemon
  Penstemon tolmiei Hook. -- not accepted
  Penstemon wrightii Hook. -- accepted -- Wright's beardtongue
  Pentaraphia acaulis (L.) Benth. & Hook. f. ex Fawc. -- not accepted
  Pentaraphia calycosa (Hook.) Decne. -- not accepted
  Pentaraphia floribunda (Lem.) Benth. & Hook. f. ex Carričre -- not accepted
  Pentaraphia neglecta (W. Hook.) Hanst. -- not accepted
  Peperomia leptostachya Hook. & Arn. -- not accepted -- aridland peperomia
  Peperomia maculosa (L.) Hook. -- accepted -- spotted peperomia
  Peperomia membranacea Hook. & Arn. -- accepted -- woodland peperomia
  Peperomia polystachya (Ait.) Hook. -- accepted
  Peperomia tetraphylla Hook. & Arn. -- accepted -- acorn peperomia
  Peramium decipiens (Hook.) Piper -- not accepted
  Perideridia gairdneri (Hook. & Arn.) Mathias -- accepted -- common yampah, Gardner's yampah, Indian caraway
  Perideridia gairdneri ssp. gairdneri (Hook. & Arn.) Mathias -- accepted -- Gairdner's yampah
  Peritoma lutea (Hook.) Raf. -- accepted -- yellow spiderflower
  Perizoma rhomboidea (Gillies & Hook.) Small -- not accepted
  Petalostemon ornatus Douglas ex Hook. -- not accepted
  Petunia integrifolia (Hook.) Schinz & Thell. -- accepted -- violetflower petunia
  Peucedanum farinosum Geyer ex Hook. -- not accepted
  Pfaffia grandiflora (Hook.) R.E. Fr. -- accepted -- jojo
  Phaca americana (Hook.) Rydb. ex Britton & A. Br. -- not accepted
  Phaca frigida var. americana Hook. -- not accepted
  Phacelia congesta Hook. -- accepted -- blue curls, caterpillars, spike phacelia
  Phacelia lutea (Hook. & Arn.) J.T. Howell -- accepted -- yellow phacelia
  Phacelia lutea var. lutea (Hook. & Arn.) J.T. Howell -- accepted -- yellow phacelia
  Phalaris californica Hook. & Arn. -- accepted -- California canarygrass
  Phelipaea pinorum (Geyer ex Hook.) A. Gray -- not accepted
  Philodendron fragrantissimum (Hook.) G. Don -- accepted -- shortstem philodendron
  Philonotis fontana var. falcata (Hook.) Brid. -- not accepted
  Phinaea albolineata (Hook.) Benth. ex Hemsl. -- accepted
  Phinaea caripensis (Klotzsch ex Hanst.) Benth. & Hook. f. ex Soler. -- not accepted
  Phinaea parviflora (A. Braun & Bouché) Benth. & Hook. f. ex Soler. -- not accepted
  Phippsia arctica (Hook.) Á. Löve & D. Löve -- not accepted
  Phlox douglasii Hook. -- not accepted
  Phlox douglasii var. douglasii Hook. -- not accepted
  Phlox drummondii Hook. -- accepted -- annual phlox, Drummond's phlox
  Phlox drummondii ssp. drummondii Hook. -- accepted -- annual phlox, Drummond's phlox
  Phlox gracilis (Hook.) Greene -- not accepted -- slender phlox
  Phlox gracilis ssp. gracilis (Hook.) Greene -- not accepted -- pink microsteris, slender phlox
  Phlox gracilis var. humilior (Hook.) B. Boivin -- not accepted
  Phlox longifolia var. linearifolia (Hook.) Brand -- not accepted
  Phlox richardsonii Hook. -- accepted -- Richardson's phlox
  Phlox richardsonii ssp. richardsonii Hook. -- accepted -- Richardson's phlox
  Phlox sibirica ssp. richardsonii (Hook.) Hultén -- not accepted
  Phlox sibirica var. richardsonii (Hook.) S.L. Welsh -- not accepted
  Pholisma Nutt. ex Hook. -- accepted
  Pholisma arenarium Nutt. ex Hook. -- accepted -- desert Christmas tree
  Phyllanthus distichus Hook. & Arn. -- accepted -- pamakani mahu
  Phyllodoce aleutica ssp. glanduliflora (Hook.) Hultén -- not accepted
  Phyllodoce glanduliflora (Hook.) Coville -- accepted -- yellow mountain heather, yellow mountainheath
  Phyllodoce X intermedia (Hook.) Rydb. (pro sp.) -- accepted -- hybrid mountainheath
  Phyllospadix Hook. -- accepted -- surfgrass
  Phyllospadix scouleri Hook. -- accepted -- Scouler's surfgrass
  Phymaspermum parvifolium (DC.) Benth. & Hook. f. -- accepted
  Physalis grandiflora Hook. -- not accepted
  Physaria didymocarpa (Hook.) A. Gray -- accepted -- common twinpod
  Physaria didymocarpa ssp. didymocarpa (Hook.) A. Gray -- accepted -- common twinpod
  Physaria didymocarpa var. didymocarpa (Hook.) A. Gray -- not accepted -- common twinpod
  Physaria geyeri (Hook.) A. Gray -- accepted -- Geyer's twinpod
  Physaria geyeri ssp. geyeri (Hook.) A. Gray -- accepted -- Geyer's twinpod
  Physaria geyeri var. geyeri (Hook.) A. Gray -- not accepted -- Geyer's twinpod
  Physaria gracilis (Hook.) O'Kane & Al-Shehbaz -- accepted -- spreading bladderpod
  Physaria gracilis ssp. gracilis (Hook.) O'Kane & Al-Shehbaz -- accepted -- spreading bladderpod
  Physodeira bicolor (Hook.) Hanst. -- not accepted
  Picradenia richardsonii Hook. -- not accepted
  Pieris floribunda (Pursh) Benth. & Hook. f. -- accepted -- mountain fetterbush
  Pieris mariana (L.) Benth. & Hook. f. -- not accepted
  Pieris nitida (W. Bartram ex Marshall) Benth. & Hook. f. -- not accepted
  Pieris phillyreifolia (Hook.) DC. -- accepted -- climbing fetterbush
  Pieris phyllyreifolia (Hook.) DC. -- not accepted
  Pilea peploides (Gaudich.) Hook. & Arn. -- accepted -- Pacific Island clearweed
  Pimelea physodes Hook. -- accepted
  Pinus lasiocarpa Hook. -- not accepted
  Pipturus albidus (Hook. & Arn.) A. Gray -- accepted -- Waimea pipturus
  Pisophaca flexuosa (Douglas ex Hook.) Rydb. -- not accepted
  Pittosporum glabrum Hook. & Arn. -- accepted -- Koolau Range cheesewood
  Pityrogramma calomelanos var. aureoflava (Hook.) Weath. ex L.H. Bailey -- not accepted
  Plagiobothrys fulvus (Hook. & Arn.) I.M. Johnst. -- accepted -- fulvous popcornflower
  Plagiobothrys fulvus var. fulvus (Hook. & Arn.) I.M. Johnst. -- accepted -- fulvous popcornflower
  Plagiobothrys scouleri (Hook. & Arn.) I.M. Johnst. -- accepted -- meadow popcornflower, Scouler's popcornflower
  Plagiobothrys scouleri var. scouleri (Hook. & Arn.) I.M. Johnst. -- not accepted -- Scouler's popcornflower
  Plagiobothrys tenellus (Nutt. ex Hook.) A. Gray -- accepted -- Pacific popcornflower
  Plagiobryum demissum (Hook.) Lindb. -- accepted -- plagiobryum moss
  Plagiochila aculeata (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Plagiochila ansata (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Plagiochila circinalis var. hemicardia (Hook.f. & Taylor) J.J. Engel & G.L. Merr. -- accepted
  Plagiochila colensoi Hook.f. & Taylor -- accepted
  Plagiochila colensoi var. colensoi Hook.f. & Taylor -- accepted
  Plagiochila fuscella (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Plagiochila fuscella var. fuscella (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Plagiochila gigantea (Hook.) Lindenb. -- accepted
  Plagiochila gigantea var. gigantea (Hook.) Lindenb. -- accepted
  Plagiochila gregaria (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Plagiochila heterodonta (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Plagiochila incurvicolla (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Plagiochila incurvicolla var. incurvicolla (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Plagiochila intertexta Hook.f. & Taylor -- accepted
  Plagiochila minutula (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Plagiochila ramosissima (Hook.) Lindenb. -- accepted
  Plagiochila uncialis (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Platanthera dilatata var. angustifolia Hook. -- not accepted
  Plectopoma fimbriatum (Hook.) Hanst. -- not accepted
  Pleuroclada albescens (Hook.) Spruce -- not accepted
  Pleuroclada albescens var. albescens (Hook.) Spruce -- not accepted
  Pleurocladula albescens (Hook.) Grolle -- not accepted
  Pleurocladula albescens var. albescens (Hook.) Grolle -- not accepted
  Pleuropogon sabinei var. elatior Hook. -- not accepted
  Pleuropogon sabinei var. humilior Hook. -- not accepted
  Pleuropus leskeoides (Hook.) Steere -- not accepted
  Pleurothallis aristata Hook. -- accepted -- forest bonnet orchid
  Pleurothallis racemiflora Lindl. ex Hook. -- accepted -- ladies' bonnet orchid, Pleurothallis fragante
  Pleurozia conchifolia (Hook. & Arn.) Austin -- accepted
  Pleurozia conchifolia var. conchifolia (Hook. & Arn.) Austin -- accepted
  Poa alopecurus ssp. fuegiana (Hook. f.) D.M. Moore & Dogg. -- accepted
  Poa antarctica (Hook. f.) Stapf -- not accepted
  Poa arctica f. vivipara (Hook.) Scoggan -- not accepted
  Poa arctica var. vivipara Hook. -- not accepted
  Poa caespitosa (G. Forst.) Hook. ex Speg. -- not accepted
  Poa flabellata (Lam.) Hook. f. -- not accepted
  Poa flexuosa var. vivipara (Hook.) Lange -- not accepted
  Poa fuegiana (Hook. f.) Hack. -- not accepted
  Poa fuegiana var. fuegiana (Hook. f.) Hack. -- not accepted
  Poa nervosa (Hook.) Vasey -- accepted -- Wheeler bluegrass
  Poa nervosa var. nervosa (Hook.) Vasey -- not accepted -- nerved bluegrass
  Poa pratensis var. stricta Hook. -- not accepted
  Poa scaberula Hook. f. -- accepted
  Podomitrium phyllanthus (Hook.) Mitt. -- accepted
  Podophyllum emodi Wall. ex Hook. f. & Thomson -- not accepted
  Poinciana gilliesii Wall. ex Hook. -- not accepted
  Poinsettia strigosa (Hook. & Arn.) Arthur -- not accepted
  Polemonium pulcherrimum Hook. -- accepted -- pretty Jacob's-ladder, skunkleaf polemonium
  Polemonium pulcherrimum ssp. pulcherrimum Hook. -- accepted -- pretty Jacob's-ladder
  Polemonium pulcherrimum var. pulcherrimum Hook. -- not accepted
  Polianthes maculosa (Hook.) Shinners -- not accepted
  Polygala cruciata var. cuspidata (Hook. & Arn.) Alph. Wood -- not accepted
  Polygonum campanulatum Hook. f. -- not accepted -- bellflower smartweed
  Polygonum cuspidatum var. compactum (Hook. f.) L.H. Bailey -- not accepted
  Polypodium phyllitidis var. latum (T. Moore) Hook. -- not accepted
  Polypodium scouleri Hook. & Grev. -- accepted -- leathery polypody
  Polypodium vulgare ssp. occidentale (Hook.) Hultén -- not accepted
  Polypodium vulgare var. intermedium (Hook. & Arn.) Fernald -- not accepted
  Polypodium vulgare var. occidentale Hook. -- not accepted
  Polypogon chonoticus Hook. f. -- not accepted
  Polypogon littoralis var. muticus Hook. f. -- not accepted
  Polystachya Hook. -- accepted -- yellowspike orchid
  Polystachya foliosa (Hook.) Rchb. f. -- accepted -- lesser yellowspike orchid
  Polystachya luteola (Sw.) Hook. -- not accepted
  Polystichum tsus-simense (Hook.) J. Sm. -- not accepted -- Korean rockfern, Tsussima hollyfern
  Polystichum tsussimense (Hook.) J. Sm. -- not accepted -- Korean rockfern
  Populus trichocarpa Torr. & A. Gray ex Hook. -- accepted -- black cottonwood
  Porella crispata (Hook.) Trevis. -- accepted
  Porotrichum neckeroides (Hook.) Williams -- not accepted
  Porterella carnosula (Hook. & Arn.) Torr. -- accepted -- fleshy porterella, porterplant
  Portulaca grandiflora Hook. -- accepted -- mossrose, rose moss
  Potentilla bipinnatifida Douglas ex Hook. -- accepted -- tansy cinquefoil
  Potentilla bipinnatifida var. bipinnatifida Douglas ex Hook. -- not accepted -- tansy cinquefoil
  Potentilla bipinnatifida var. glabrata (Lehm. ex Hook.) Kohli & Packer -- not accepted -- tansy cinquefoil
  Potentilla congesta (Douglas ex Hook.) Baill. -- not accepted
  Potentilla douglasii var. parviflora (Nutt. ex Hook. & Arn.) J.T. Howell -- not accepted -- pinewoods horkelia
  Potentilla flabellifolia Hook. ex Torr. & A. Gray -- accepted -- high mountain cinquefoil, Mount Rainier cinquefoil
  Potentilla gordonii (Hook.) Greene -- not accepted
  Potentilla gracilis Douglas ex Hook. -- accepted -- graceful cinquefoil, northwest cinquefoil, slender cinquefoil
  Potentilla gracilis var. gracilis Douglas ex Hook. -- accepted -- graceful cinquefoil
  Potentilla pensylvanica var. bipinnatifida (Douglas ex Hook.) Torr. & A. Gray -- not accepted
  Potentilla pensylvanica var. glabrata (Lehm. ex Hook.) S. Watson -- not accepted
  Potentilla unguiculata (A. Gray) Hook. f. -- not accepted
  Pottia wilsonii (Hook.) Bruch & Schimp. in B.S.G. -- accepted -- Wilson's pottia moss
  Prenanthes alata (Hook.) D. Dietr. -- accepted -- western rattlesnakeroot
  Prestoea Hook. f. -- accepted -- prestoea
  Primulina sinensis Hook. f. -- not accepted
  Prionolobus turneri (Hook.) Schiffn. -- not accepted
  Prosartes smithii (Hook.) Utech, Shinwari & Kawano -- accepted -- largeflower fairybells
  Prosopis humilis Gillies ex Hook. & Arn. -- accepted -- mesquite
  Prosopis sericantha Gillies ex Hook. & Arn. -- accepted -- mesquite
  Prosthechea pygmaea (Hook.) W.E. Higgins -- accepted -- dwarf butterfly orchid
  Protolophozia multicuspidata (Hook.f. & Taylor) Vána & L. Söderstr. -- accepted
  Prunus africana (Hook. f.) Kalkman -- accepted
  Prunus emarginata var. mollis (Douglas ex Hook.) W.H. Brewer -- not accepted -- bitter cherry
  Prunus glandulosa (Hook.) Torr. & A. Gray -- not accepted
  Prunus ilicifolia (Nutt. ex Hook. & Arn.) D. Dietr. -- accepted -- hollyleaf cherry
  Prunus ilicifolia ssp. ilicifolia (Nutt. ex Hook. & Arn.) D. Dietr. -- not accepted -- hollyleaf cherry
  Prunus ilicifolia var. ilicifolia (Nutt. ex Hook. & Arn.) D. Dietr. -- accepted -- hollyleaf cherry
  Prunus pensylvanica var. mollis (Douglas ex Hook.) B. Boivin -- not accepted
  Pseudomarsupidium decipiens (Hook.) Grolle -- accepted
  Psoralea physodes Douglas ex Hook. -- not accepted
  Psoralea strobilina Hook. & Arn. -- not accepted
  Pteris cretica var. albolineata Hook. -- accepted -- Cretan brake
  Pterygoloma repens (Hook.) Hanst. -- not accepted
  Pteryxia terebinthina (Hook.) J.M. Coult. & Rose -- accepted -- smoothshore springparsley, Terebinth springparsley, turpentine wavewing
  Pteryxia terebinthina var. terebinthina (Hook.) J.M. Coult. & Rose -- accepted -- turpentine wavewing
  Ptilocalais nutans (Hook.) Greene -- not accepted
  Ptychosperma macarthurii (H. Wendl. ex H.J. Veitch) H. Wendl. ex Hook f. -- accepted
  Puccinellia arctica (Hook.) Fernald & Weath. -- accepted -- arctic alkaligrass
  Puccinellia magellanica (Hook. f.) Parodi -- accepted
  Pyrola asarifolia ssp. bracteata (Hook.) Haber -- accepted -- bog wintergreen, long-bracted wintergreen, pink wintergreen
  Pyrola asarifolia var. bracteata (Hook.) Jeps. -- not accepted
  Pyrola bracteata Hook. -- not accepted
  Pyrola rotundifolia var. asarifolia (Michx.) Hook. -- not accepted
  Pyrola rotundifolia var. bracteata (Hook.) A. Gray -- not accepted
  Pyrrocoma Hook. -- accepted -- goldenweed
  Pyrrocoma carthamoides Hook. -- accepted -- largeflower goldenweed
  Pyrrocoma carthamoides var. carthamoides Hook. -- accepted -- largeflower goldenweed
  Pyrrocoma lanceolata (Hook.) Greene -- accepted -- lance-leaf goldenweed, lanceleaf goldenweed
  Pyrrocoma lanceolata var. lanceolata (Hook.) Greene -- accepted -- Intermountain goldenweed, lance goldenweed, lanceleaf goldenweed
  Pyrrocoma uniflora (Hook.) Greene -- accepted -- plantain goldenweed
  Pyrrocoma uniflora var. uniflora (Hook.) Greene -- accepted -- plantain goldenweed, singlehead goldenweed
  Quercus douglasii Hook. & Arn. -- accepted -- blue oak
  Quercus garryana Douglas ex Hook. -- accepted -- Oregon white oak
  Quercus garryana var. garryana Douglas ex Hook. -- accepted -- Oregon white oak
  Raddia concinna (Hook. f.) Chase -- not accepted
  Radicula curvisiliqua (Hook.) Greene -- not accepted
  Radula aneurismalis (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Radula aquilegia (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Radula buccinifera (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Radula flavifolia (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Radula fulvifolia (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Radula helix (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Radula marginata (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Radula strangulata Hook.f. & Taylor -- accepted
  Radula uvifera (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Raimannia drummondii (Hook.) Rose -- not accepted
  Ramonda heldreichii (Boiss.) Benth. & Hook. f. ex C.B. Clarke -- not accepted
  Ranunculus bonariensis var. trisepalus (Gillies ex Hook. & Arn.) Lourteig -- accepted -- Carter's buttercup
  Ranunculus cardiophyllus Hook. -- accepted -- heart-leaf buttercup, heartleaf buttercup
  Ranunculus cymbalaria var. alpinus Hook. -- not accepted
  Ranunculus flammula var. filiformis (Michx.) Hook. -- not accepted -- greater creeping spearwort
  Ranunculus glaberrimus Hook. -- accepted -- sagebrush buttercup
  Ranunculus glaberrimus var. glaberrimus Hook. -- accepted -- sagebrush buttercup
  Ranunculus hebecarpus Hook. & Arn. -- accepted -- delicate buttercup, downy-fruit buttercup
  Ranunculus orthorhynchus Hook. -- accepted -- straightbeak buttercup
  Ranunculus orthorhynchus var. orthorhynchus Hook. -- accepted -- straightbeak buttercup
  Ranunculus reptans var. intermedius (Hook.) Torr. & A. Gray -- not accepted
  Ranunculus trisepalus Gillies ex Hook. & Arn. -- not accepted
  Rechsteineria cochlearis (Hook.) Kuntze -- not accepted
  Rechsteineria elliptica (Hook.) Kuntze -- not accepted
  Rechsteineria lindleyi (Hook.) Fritsch -- not accepted
  Rechsteineria marchii (Wailes ex Hook.) Kuntze -- not accepted
  Rechsteineria stricta (Hook. & Arn.) Kuntze -- not accepted
  Relbunium (Endl.) Benth. & Hook. f. -- not accepted
  Rhabdonia J.D. Hooker & Harvey -- accepted
  Rhodanthe chlorocephala ssp. rosea (Hook.) P. Wilson -- accepted
  Rhododendron albiflorum Hook. -- accepted -- Cascade azalea, white rhododendron
  Rhododendron albiflorum var. albiflorum Hook. -- not accepted -- Cascade azalea
  Rhododendron californicum Hook. -- not accepted
  Rhus integrifolia (Nutt.) Benth. & Hook. f. ex W.H. Brewer & S. Watson -- accepted -- lemonade sumac
  Rhynchoglossum zeylanicum Hook. -- not accepted
  Rhynchosia senna Gillies ex Hook. & Arn. -- accepted -- Texas snout-bean, Texas snoutbean
  Rhynchosia tomentosa (L.) Hook. & Arn. -- accepted -- twining snoutbean
  Rhynchosia tomentosa var. tomentosa (L.) Hook. & Arn. -- accepted -- twining snoutbean
  Rhynchospora sclerioides Hook. & Arn. -- accepted -- Hawai'i beaksedge
  Rhynchotechum X latifolium Hook. f. & Thoms. ex C.B. Clarke -- not accepted
  Rhytidiopsis robusta (Hook.) Broth. -- accepted -- robust rhytidiopsis moss
  Rhytidiopsis robustus (W.J. Hooker) W.J. Brotherus -- accepted
  Rhytidophyllum auriculatum Hook. -- accepted -- tibey-amarillo
  Ribes bracteosum Douglas ex Hook. -- accepted -- stink currant
  Ribes californicum Hook. & Arn. -- accepted -- hillside gooseberry
  Ribes californicum var. californicum Hook. & Arn. -- accepted -- hillside gooseberry
  Ribes hirtellum var. saxosum (Hook.) Fernald -- not accepted
  Ribes oxyacanthoides var. saxosum (Hook.) Coville -- not accepted
  Ribes subvestitum Hook. & Arn. -- not accepted
  Riccardia alcicornis (Hook.f. & Taylor) Trevis. -- accepted
  Riccardia cochleata (Hook.f. & Taylor) Kuntze -- accepted
  Riccardia eriocaula (Hook.) C. Massal. -- accepted
  Riccardia latifrons var. sinuata (Dicks. ex Hook.) Lindb. -- not accepted
  Riccardia nana (Hook.f. & Taylor) Trevis. -- accepted
  Riccardia prehensilis (Hook.f. & Taylor) C. Massal. -- accepted
  Riccardia sinuata (Dicks. ex Hook.) Trevis. -- not accepted
  Riccardia sinulata (Dicks. ex Hook.) Trevis. -- not accepted
  Riccardia submersa (Hook.f. & Taylor) Trevis. -- accepted
  Rorippa curvisiliqua (Hook.) Bessey ex Britton -- accepted -- curvepod yellowcress
  Rorippa curvisiliqua var. curvisiliqua (Hook.) Bessey ex Britton -- not accepted -- curvepod yellowcress
  Rubus macropetalus Douglas ex Hook. -- not accepted
  Rubus nivalis Douglas ex Hook. -- accepted -- snow raspberry
  Rubus parviflorus ssp. velutinus (Hook. & Arn.) Roy L. Taylor & MacBryde -- not accepted
  Rubus parviflorus var. velutinus (Hook. & Arn.) Greene -- not accepted -- thimbleberry
  Rubus spectabilis var. menziesii (Hook.) S. Watson -- not accepted
  Rubus ursinus ssp. macropetalus (Douglas ex Hook.) Roy L. Taylor & MacBryde -- not accepted -- California blackberry
  Rubus ursinus var. macropetalus (Douglas ex Hook.) S.W. Br. -- not accepted
  Ruellia ciliatiflora Hook. -- accepted -- hairyflower wild petunia
  Rufacer drummondii (Hook. & Arn. ex Nutt.) Small -- not accepted
  Rupertia physodes (Douglas ex Hook.) J.W. Grimes -- accepted -- forest scurfpea
  Rytidophyllum auriculatum Hook. -- not accepted -- tibey amarillo
  Rytidosperma buchananii (Hook. f.) Connor & Edgar -- accepted
  Rytidosperma gracile (Hook. f.) Connor & Edgar -- accepted
  Rytidosperma nudum (Hook. f.) Connor & Edgar -- accepted
  Rytidosperma setifolium (Hook. f.) Connor & Edgar -- accepted
  Sabatia macrophylla Hook. -- accepted -- largeleaf rose gentian
  Sabatia macrophylla var. macrophylla Hook. -- accepted -- largeleaf rose gentian
  Sabatia maculata (Benth.) Benth. & Hook. f. -- not accepted
  Sabina occidentalis (Hook.) A. Heller -- not accepted
  Saccharum chinense Nees ex Hook. & Arn. -- not accepted
  Saccharum modhara Hook. f. -- not accepted
  Saccogynidium vasculosum (Hook.f. & Taylor) Grolle -- accepted
  Sadleria pallida Hook. & Arn. -- accepted -- ama'u
  Salisia pallidiflora (Hook.) Regel -- not accepted
  Salix acutifolia auct. non Hook. -- not accepted
  Salix adenophylla Hook. -- not accepted
  Salix balsamifera (Hook.) Barratt ex Andersson -- not accepted
  Salix barrattiana Hook. -- accepted -- Barratt's willow
  Salix brachystachys var. scouleriana (Barratt ex Hook.) Andersson -- not accepted
  Salix cordata var. balsamifera Hook. -- not accepted
  Salix cordata var. mackenzieana Hook. -- not accepted
  Salix drummondiana Barratt ex Hook. -- accepted -- Drummond's willow
  Salix eriocephala ssp. mackenzieana (Hook.) Dorn -- not accepted
  Salix eriocephala var. mackenzieana (Hook.) Dorn -- not accepted
  Salix flavescens var. scouleriana (Barratt ex Hook.) Bebb -- not accepted
  Salix glauca ssp. acutifolia (Hook.) Hultén -- not accepted
  Salix glauca ssp. glauca var. acutifolia (Hook.) C.K. Schneid. -- not accepted
  Salix glauca ssp. glauca var. villosa (D. Don ex Hook.) Andersson -- not accepted
  Salix glauca var. acutifolia (Hook.) C.K. Schneid. -- accepted -- grayleaf willow
  Salix glauca var. villosa (D. Don ex Hook.) Andersson -- accepted -- grayleaf willow
  Salix glauca var. villosa auct. non (D. Don ex Hook.) Andersson -- not accepted
  Salix glaucops var. villosa (D. Don ex Hook.) Andersson -- not accepted
  Salix hookerana Barratt ex Hook. -- not accepted
  Salix hookeriana Barratt ex Hook. -- accepted -- dune willow
  Salix lanata ssp. richardsonii (Hook.) A.K. Skvortsov -- not accepted -- Richardson's willow
  Salix mackenzieana (Hook.) Barratt ex Andersson -- not accepted
  Salix nivalis Hook. -- accepted -- snow willow
  Salix reticulata ssp. nivalis (Hook.) Á. Löve & D. Löve & B.M. Kapoor -- not accepted -- snow willow
  Salix reticulata var. nivalis (Hook.) Andersson -- not accepted
  Salix richardsonii Hook. -- accepted -- Richardson's willow
  Salix rigida ssp. mackenzieana (Hook.) A.E. Murray -- not accepted
  Salix rigida var. mackenzieana (Hook.) Cronquist -- not accepted
  Salix scoulerana Barratt ex Hook. -- not accepted -- Scouler's willow
  Salix scouleriana Barratt ex Hook. -- accepted -- Scouler's willow
  Salix speciosa Hook. & Arn. -- not accepted
  Salix vestita var. nana Hook. -- not accepted
  Salix villosa D. Don ex Hook. -- not accepted
  Salix villosa var. acutifolia Hook. -- not accepted
  Salpichroa rhomboidea (Gillies & Hook.) Miers -- not accepted
  Sanchezia nobilis Hook. f. -- not accepted
  Sanguisorba canadensis ssp. latifolia (Hook.) Calder & Roy L. Taylor -- not accepted
  Sanguisorba canadensis var. latifolia Hook. -- not accepted
  Sanicula arctopoides Hook. & Arn. -- accepted -- footsteps of spring
  Sanicula bipinnata Hook. & Arn. -- accepted -- poison sanicle
  Sanicula bipinnatifida Douglas ex Hook. -- accepted -- purple sanicle
  Sanicula laciniata Hook. & Arn. -- accepted -- coastal blacksnakeroot
  Sansevieria cylindrica Bojer ex Hook. -- accepted -- African bowstring hemp
  Santalum paniculatum Hook. & Arn. -- accepted -- mountain sandalwood
  Santalum paniculatum var. paniculatum Hook. & Arn. -- accepted -- mountain sandalwood
  Sapindus drummondii Hook. & Arn. -- not accepted
  Sapindus saponaria var. drummondii (Hook. & Arn.) L.D. Benson -- accepted -- western soapberry
  Sarcobatus vermiculatus (Hook.) Torr. -- accepted -- black greasewood, greasewood
  Sarcobatus vermiculatus var. vermiculatus (Hook.) Torr. -- not accepted -- greasewood
  Sarothra drummondii Grev. & Hook. -- not accepted
  Satureja coccinea (Nutt. ex Hook.) Bertol. -- not accepted
  Saussurea densa (Hook.) Rydb. -- not accepted -- clustered sawwort
  Saussurea nuda ssp. densa (Hook.) G.W. Douglas -- not accepted
  Saussurea nuda var. densa (Hook.) Hultén -- not accepted
  Saxifraga integrifolia Hook. -- not accepted -- wholeleaf saxifrage
  Saxifraga reflexa Hook. -- not accepted -- reflexed saxifrage
  Saxifraga reflexa var. reflexa Hook. -- not accepted
  Saxifraga richardsonii Hook. -- not accepted
  Saxifraga umbellulata Hook. f. & Thomson -- accepted
  Scabrethia scabra (Hook.) W.A. Weber -- accepted -- badlands mule-ears
  Scabrethia scabra ssp. scabra (Hook.) W.A. Weber -- accepted -- badlands mule-ears
  Scaevola gaudichaudi Hook. & Arn. -- not accepted -- mountain naupaka
  Scaevola gaudichaudii Hook. & Arn. -- accepted -- ridgetop naupaka
  Scaevola glabra Hook. & Arn. -- accepted -- 'ohe naupaka
  Scaevola mollis Hook. & Arn. -- accepted -- purple naupaka
  Schiedea menziesii Hook. -- accepted -- Menzies' schiedea
  Schiedea nuttallii Hook. -- accepted -- valley schiedea
  Schistidium serratum J.D. Hooker & W. Wilson -- not accepted
  Schistochila appendiculata (Hook.) Dumort. ex Trevis. -- accepted
  Schistochila balfouriana (Hook.f. & Taylor) Steph. -- accepted
  Schistochila berteroana (Hook.) Steph. -- accepted
  Schistochila glaucescens (Hook.) A. Evans -- accepted
  Schistochila lamellata (Hook.) Dumort. ex A. Evans -- accepted
  Schistochila laminigera (Hook.f. & Taylor) A. Evans -- accepted
  Schistochila nobilis (Hook.) Trevis. -- accepted
  Schistochila pinnatifolia (Hook.) Trevis. -- accepted
  Schistochila repleta (Hook.f. & Taylor) Steph. -- accepted
  Schistochila splachnophylla (Hook.f. & Taylor) Steph. -- accepted
  Schistochila tuloides (Hook.f. & Taylor) Steph. -- accepted
  Schizocaena J. Sm. ex Hook. -- not accepted
  Schizocaena alternans (Hook.) J. Sm. -- not accepted
  Schkuhria multiflora Hook. & Arn. -- accepted -- many-flower false threadleaf, manyflower false threadleaf
  Schkuhria multiflora var. multiflora Hook. & Arn. -- not accepted
  Schlotheimia rugifolia (Hook.) Schwaegr. -- accepted -- ruggedleaf schlotheimia moss
  Schlumbergera russelliana (Hook.) Britton & Rose -- accepted
  Schoenus tendo Banks & Sol. ex Hook. f. -- accepted -- bogrush
  Scirpus carinatus (Hook. & Arn. ex Torr.) A. Gray, non Sm. -- not accepted
  Scorzonella laciniata (Hook.) Sch. Bip. -- not accepted
  Scorzonella nutans Hook. -- not accepted
  Scouleria Hook. in Drumm. -- accepted -- splashzone moss
  Scouleria aquatica Hook. in Drumm. -- accepted -- blackmat splashzone moss
  Sedum douglasii Hook. -- not accepted
  Sedum sieboldii Sweet ex Hook. -- not accepted -- Siebold's stonecrop
  Sedum spathulifolium Hook. -- accepted -- broadleaf stonecrop
  Sedum spathulifolium ssp. spathulifolium Hook. -- not accepted -- broadleaf stonecrop
  Sedum spathulifolium var. spathulifolium Hook. -- accepted -- broadleaf stonecrop
  Selaginella douglasii (Hook. & Grev.) Spring -- accepted -- Douglas' spikemoss
  Selaginella lepidophylla (Hook. & Grev.) Spring -- accepted -- flower of stone
  Selaginella menziesii (Hook. & Grev.) Spring -- not accepted -- Menzies' spikemoss
  Selenicereus macdonaldiae (Hook.) Britton & Rose -- not accepted
  Senecio ampullaceus Hook. -- accepted -- Texas ragwort
  Senecio aureus var. gracilis (Pursh) Hook. -- not accepted
  Senecio cannabinifolius Hook. & Arn. -- accepted -- hempleaf ragwort
  Senecio canus Hook. -- not accepted -- woolly groundsel
  Senecio discoideus (Hook.) Britton -- not accepted
  Senecio palustris (L.) Hook. -- not accepted
  Senecio serra Hook. -- accepted -- butterweed, butterweed groundsel, tall ragwort
  Senecio serra var. serra Hook. -- accepted -- tall groundsel, tall ragwort
  Senecio triangularis Hook. -- accepted -- arrowleaf groundsel, arrowleaf ragwort
  Senecio websteri Greenm. non Hook. f. -- not accepted
  Senkenbergia coulteri Hook. f. -- not accepted
  Senna gaudichaudii (Hook. & Arn.) H.S. Irwin & Barneby -- accepted -- Gaudichaud's senna
  Serenoa Hook. f. -- accepted -- serenoa
  Sesbania tomentosa Hook. & Arn. -- accepted -- `ohai, Oahu riverhemp
  Sicyos pachycarpus Hook. & Arn. -- accepted -- paha
  Sida hederacea (Douglas ex Hook.) Torr. ex A. Gray -- not accepted -- alkali mallow, alkali sida, dollar weed
  Sida leprosa var. hederacea (Douglas ex Hook.) K. Schum. -- not accepted
  Sidalcea malachroides (Hook. & Arn.) A. Gray -- accepted -- mapleleaf checkerbloom
  Sideroxylon sandwicense (A. Gray) Benth. & Hook. ex Hillebr. -- not accepted -- 'ala'a
  Sieglingia antarctica (Hook. f.) Macloskie -- not accepted
  Silene douglasii Hook. -- accepted -- Douglas' campion, Douglas' catchfly, seabluff catchfly
  Silene douglasii var. douglasii Hook. -- accepted -- Douglas' campion, Douglas' catchfly, seabluff catchfly
  Silene drummondii Hook. -- accepted -- Drummond's campion, Drummond's catchfly, Drummond's cockle
  Silene drummondii ssp. drummondii Hook. -- accepted -- Drummond's campion
  Silene drummondii var. drummondii Hook. -- not accepted -- Drummond's campion, Drummond's catchfly
  Silene menziesii Hook. -- accepted -- Menzies' campion, white catchfly
  Silene menziesii ssp. menziesii Hook. -- not accepted -- Menzies' campion, Menzies' catchfly
  Silene menziesii ssp. menziesii var. menziesii Hook. -- not accepted
  Silene menziesii var. menziesii Hook. -- not accepted -- Menzies' campion
  Silene scouleri Hook. -- accepted -- Scouler's campion, Scouler's catchfly, simple campion
  Silene scouleri ssp. scouleri Hook. -- accepted -- simple campion
  Silene scouleri ssp. scouleri var. scouleri Hook. -- not accepted -- simple campion
  Silene scouleri var. scouleri Hook. -- not accepted -- simple campion
  Silphium asperimum Hook. -- not accepted
  Silphium asperrimum Hook. -- not accepted
  Silphium integrifolium var. asperrimum (Hook.) B.L. Turner -- not accepted
  Sinningia carolinae (Wawra) Benth. & Hook. f. ex Seibert & Voss -- not accepted
  Sinningia cochlearis (Hook.) Chautems -- accepted
  Sinningia concinna (Hook. f.) Nichols. -- accepted
  Sinningia gracilis (Mart.) Benth. & Hook. f. ex Fritsch -- not accepted
  Sinningia macrophylla (Nees & Mart.) Benth. & Hook. f. ex Fritsch -- accepted
  Sinningia maximiliana (Hanst.) Benth. & Hook. ex Fritsch -- accepted
  Sinningia stricta (Hook. & Arn.) Wiehler -- not accepted
  Sinningia tubiflora (Hook.) Fritsch -- accepted
  Sisymbrium curvisiliqua Hook. -- not accepted
  Sisymbrium sophioides Fisch. ex Hook. -- not accepted
  Sisyrinchium chilense Hook. -- not accepted -- swordleaf blue-eyed grass
  Smilax herbacea var. lasioneura (Hook.) A. DC. -- not accepted
  Smilax lasioneura Hook. -- accepted -- Blue Ridge carrion-flower, Blue Ridge carrionflower
  Smilax lasioneuron Hook. -- not accepted
  Solanum acanthodes Hook.f. -- accepted
  Solanum amblophyllum Hook. -- accepted
  Solanum edmondstonii Hook.f. -- accepted
  Solanum refractum Hook. & Arn. -- accepted
  Solanum sandwicense Hook. & Arn. -- accepted -- `aiakeakua, Hawai'i horsenettle, popolo
  Solanum tweedianum Hook. -- accepted
  Solanum wendlandii Hook. f. -- accepted -- giant potatocreeper
  Solenostoma inundatum (Hook.f. & Taylor) Mitt. ex Steph. -- accepted
  Solenostoma sphaerocarpum (Hook.) Steph. -- accepted
  Solenostoma sphearocarpa (Hook.) Steph. -- not accepted
  Solidago arguta ssp. boottii (Hook.) G. Morton -- not accepted
  Solidago arguta var. boottii (Hook.) Palmer & Steyerm. -- accepted -- Boott's goldenrod
  Solidago bicolor var. lanata (Hook.) Seymour -- not accepted
  Solidago boothii Hook. -- not accepted
  Solidago boottii Hook. -- not accepted
  Solidago hispida var. lanata (Hook.) Fernald -- not accepted -- hairy goldenrod
  Solms-laubachia platycarpa (Hook f. & Thomson) Botsch. -- accepted
  Spermolepis divaricata (Benth. & Hook. f. ex S. Watson) Raf. ex Ser. -- accepted -- forked scaleseed, roughfruit scaleseed
  Sphaeralcea grossulariifolia (Hook. & Arn.) Rydb. -- accepted -- currant-leaf globe-mallow, gooseberryleaf globemallow
  Sphaeralcea grossulariifolia ssp. grossulariifolia (Hook. & Arn.) Rydb. -- accepted -- berryleaf globemallow, gooseberryleaf globemallow
  Sphaeralcea rivularis (Douglas ex Hook.) Torr. -- not accepted
  Sphaerocionium lanceolatum (Hook. & Arn.) Copel. -- not accepted
  Sphaeropteris alternans (Hook.) R.M. Tryon -- not accepted
  Sphaeropteris assimilis (Hook.) R.M. Tryon -- not accepted
  Sphaeropteris aterrima (Hook.) R.M. Tryon -- not accepted
  Sphaeropteris brunoniana (Hook.) R.M. Tryon -- not accepted
  Sphaeropteris cooperi (Hook. ex F. Muell.) R.M. Tryon -- not accepted -- Cooper's cyathea
  Sphaeropteris crinita (Hook.) R.M. Tryon -- not accepted
  Sphaeropteris integra (J. Sm. ex Hook.) R.M. Tryon -- not accepted
  Sphaeropteris lepifera (J. Sm. ex Hook.) R.M. Tryon -- not accepted
  Sphaerorrhiza sarmentiana (Gardner ex Hook.) Roalson & Boggan -- accepted
  Sphagnum fimbriatum Wils. in Wils. & Hook.f. in Hook.f. -- accepted -- sphagnum
  Sphagnum fimbriatum var. fimbriatum Wils. in Wils. & Hook.f. in Hook.f. -- accepted -- sphagnum
  Spilanthes pusilla Hook. & Arn. -- not accepted
  Spiraea douglasii Hook. -- accepted -- rose spirea
  Spiraea douglasii ssp. menziesii (Hook.) Calder & Roy L. Taylor -- not accepted
  Spiraea douglasii var. douglasii Hook. -- accepted -- rose spirea
  Spiraea douglasii var. menziesii (Hook.) C. Presl -- accepted -- Menzies' spirea
  Spiraea dumosa Nutt. ex Hook. -- not accepted
  Spiraea menziesii Hook. -- not accepted
  Spodiopogon aureus Hook. & Arn. -- not accepted
  Sporobolus ciliatus Munro ex Hook. f. -- not accepted
  Sporobolus cryptandrus ssp. fuscicola (Hook.) E.K. Jones & Fassett -- not accepted
  Sporobolus cryptandrus ssp. fuscicolor (Hook.) E.K. Jones & Fassett -- not accepted
  Sporobolus cryptandrus var. fuscicola (Hook.) R.W. Pohl -- not accepted
  Sporobolus cuspidatus (Torr. ex Hook.) Alph. Wood -- not accepted
  Sporobolus depauperatus (Torr. ex Hook.) Scribn. -- not accepted
  Spruceanthus olivaceus (Hook.f. & Taylor) X.Q. Shi, R.L. Zhu & Gradst. -- accepted
  Stanhopea Frost ex Hook. -- accepted
  Stapelia nobilis N.E. Br. ex Hook. f. -- not accepted
  Steetzia lyellii (Hook.) Lehm. -- not accepted
  Steironema radicans (Hook.) A. Gray -- not accepted
  Stelechocarpus Hook. f. & Thomson -- accepted
  Stelechocarpus burahol (Blume) Hook. f. & Thomson -- accepted -- burahol
  Stenogastra concinna Hook. f. -- not accepted
  Stephanomeria minor (Hook.) Nutt. -- not accepted -- lesser wirelettuce
  Stephanomeria minor var. minor (Hook.) Nutt. -- not accepted -- narrowleaf wirelettuce
  Stereophyllum radiculosum (Hook.) Mitt. -- accepted -- stereophyllum moss
  Sterigmanthe bojeri (Hook.) Klotzsch & Garcke -- not accepted
  Sterigmanthe splendens (Bojer ex Hook.) Klotzsch & Garcke -- not accepted
  Sticherus owhyensis (Hook.) Ching -- not accepted -- Hawai'i umbrella fern
  Sticherus owhyhensis (Hook.) Ching -- accepted
  Stipa rariflora (Hook. f.) Benth. -- not accepted
  Streptanthus glandulosus Hook. -- accepted -- bristly jewelflower
  Streptanthus glandulosus ssp. glandulosus Hook. -- accepted -- bristly jewelflower
  Streptanthus hyacinthoides Hook. -- accepted -- smooth jewelflower, smooth twistflower
  Streptanthus maculatus ssp. obtusifolius (Hook.) Rollins -- not accepted -- clasping jewelflower
  Streptanthus obtusifolius Hook. -- not accepted
  Streptocarpus dunnii Hook. f. -- accepted
  Streptocarpus galpinii Hook. f. -- accepted
  Streptocarpus gardenii Hook. -- accepted
  Streptocarpus kirkii Hook. f. -- accepted
  Streptocarpus mahonii Hook. f. -- not accepted
  Streptocarpus parviflorus Hook. f. -- accepted
  Streptocarpus parviflorus ssp. parviflorus Hook. f. -- accepted
  Streptocarpus polyanthus Hook. -- accepted
  Streptocarpus polyanthus ssp. polyanthus Hook. -- accepted
  Streptocarpus rexii (Hook.) Lindley -- accepted
  Streptocarpus saundersii Hook. -- accepted
  Strophanthus gratus (Wall. & Hook.) Baill. -- accepted -- ouabain
  Suaeda calceoliformis (Hook.) Moq. -- accepted -- Paiuteweed, Pursh seepweed, western seepweed
  Suksdorfia ranunculifolia (Hook.) Engl. -- accepted -- buttercup suksdorfia
  Symblepharis vaginata (Hook.) Wijk & Marg. -- accepted -- symblepharis moss
  Symphoricarpos occidentalis Hook. -- accepted -- western snowberry, wolfberry
  Symphyogyna hymenophyllum (Hook.) Nees & Mont. -- accepted
  Symphyogyna hymenophyllum var. hymenophyllum (Hook.) Nees & Mont. -- accepted
  Symphyogyna rhodina (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Symphyogyna tenuinervis (Hook.f. & Taylor) Grolle -- accepted
  Symphyotrichum patens var. gracile (Hook.) G.L. Nesom -- accepted -- late purple aster
  Synadenium grantii Hook. f. -- not accepted
  Synthyris missurica ssp. major (Hook.) Pennell -- accepted
  Synthyris missurica var. major (Hook.) Pennell ex R.J. Davis -- not accepted
  Synthyris reniformis var. major Hook. -- not accepted
  Synthyris rubra (Douglas ex Hook.) Benth. -- accepted -- red kittentails
  Syzygiella acinacifolia (Hook.f. & Taylor) K. Feldberg, Vána, Hentschel & Heinrichs -- accepted
  Syzygiella tasmanica (Hook.f. & Taylor) K. Feldberg, Vána, Hentschel & Heinrichs -- accepted
  Tabebuia aurea (Silva Manso) Benth. & Hook. f. ex S. Moore -- accepted -- Caribbean trumpet-tree
  Talauma hodgsonii Hook. f. & Thomson -- accepted
  Tanacetum suaveolens (Pursh) Hook. -- not accepted
  Tauschia tenuissima (Geyer ex Hook.) Mathias & Constance -- accepted -- Leiberg's umbrellawort
  Tayloria Hook. -- accepted -- tayloria dung moss
  Tayloria splachnoides (Schleich. ex Schwaegr.) Hook. -- accepted -- splachnoid dung moss
  Telfairia Hook. -- accepted
  Telfairia occidentalis Hook. f. -- accepted -- oysternut
  Telfairia pedata (Sm. ex Sims) Hook. -- accepted -- oysternut
  Temnoma pulchellum (Hook.) Mitt. -- accepted
  Temnoma quadripartitum (Hook.) Mitt. -- accepted
  Temnoma quadripartitum var. quadripartitum (Hook.) Mitt. -- accepted
  Tenaxia cumminsii (Hook. f.) N. P. Barker & H. P. Linder -- accepted
  Tephrosia vogelii Hook. f. -- accepted -- Vogel's tephrosia
  Terrellia virginica var. submutica (Hook.) Lunell ex Hitchc. -- not accepted
  Tetracymbaliella cymbalifera (Hook.f. & Taylor) Grolle -- accepted
  Tetradema tuberculatum (Hook. f.) Schltr. -- not accepted
  Tetradymia spinosa Hook. & Arn. -- accepted -- shortspine horsebrush, spiny horsebrush
  Tetraneuris linearifolia (Hook.) Greene -- accepted -- fineleaf fournerved daisy, slimleaf actinea
  Tetraneuris linearifolia var. linearifolia (Hook.) Greene -- accepted -- fineleaf fournerved daisy
  Tetranthera californica Hook. & Arn. -- not accepted
  Tetrapanax papyrifer (Hook.) K. Koch -- accepted -- Chinese rice-paper plant, rice-paper plant, ricepaper plant
  Tetrapanax papyriferus (Hook.) K. Koch -- not accepted -- Chinese rice-paper plant, rice-paper plant, ricepaper plant
  Tetrapteron graciliflorum (Hook. & Arn.) W.L. Wagner & Hoch -- accepted -- hill suncup
  Thamnobryum neckeroides (Hook.) Lawt. -- accepted -- Necker's thamnobryum moss
  Thelesperma filifolium (Hook.) A. Gray -- accepted -- greenthread, plains greenthread, stiff greenthread
  Thelesperma filifolium var. filifolium (Hook.) A. Gray -- not accepted -- stiff greenthread
  Thelypodium flavescens (Hook.) S. Watson -- not accepted
  Thelypodium laciniatum (Hook.) Endl. ex Walp. -- accepted -- cutleaf thelypody
  Thelypodium lasiophyllum (Hook. & Arn.) Greene -- not accepted
  Thermopsis macrophylla Hook. & Arn. -- accepted -- Santa Inez goldenbanner
  Thermopsis macrophylla var. macrophylla Hook. & Arn. -- not accepted -- California goldenbanner, false-lupine, golden pea
  Therofon richardsonii (Hook.) Kuntze -- not accepted
  Thuidium crispifolium (Hook.) Lindb. -- not accepted
  Thysananthus anguiformis (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Thysananthus auriculatus (Wilson & Hook.) Sukkharak & Gradst. -- accepted
  Thysanocarpus Hook. -- accepted -- fringepod, lacepod
  Thysanocarpus curvipes Hook. -- accepted -- lacepod mustard, sand fringepod, sand lacepod
  Thysanocarpus curvipes ssp. curvipes Hook. -- accepted
  Thysanocarpus pusillus Hook. -- not accepted
  Tiarella laciniata Hook. -- not accepted
  Tiarella trifoliata ssp. unifoliata (Hook.) P.M. Kern -- not accepted
  Tiarella trifoliata var. laciniata (Hook.) Wheelock -- accepted -- threeleaf foamflower
  Tiarella trifoliata var. unifoliata (Hook.) Kurtz -- accepted -- oneleaf foamflower
  Tiarella unifoliata Hook. -- not accepted
  Tillaea erecta Hook. & Arn. -- not accepted
  Tillaea minima Miers ex Hook. & Arn. -- not accepted
  Tillandsia aloifolia Hook. -- not accepted
  Tillandsia bulbosa Hook. -- accepted -- bulbous airplant, Tillandsia base bulbosa
  Tillandsia pulchella Hook. -- not accepted
  Tiquilia nuttallii (Hook.) A.T. Richardson -- accepted -- Nuttall's crinklemat, Nuttall's tiquilia, rosette crinklemat
  Tirucalia alata (Hook.) P.V. Heath -- not accepted
  Tithonia speciosa (Hook.) Griseb. -- not accepted
  Tithymalus griffithii (Hook. f.) H. Hara -- not accepted
  Tithymalus splendens (Bojer ex Hook.) M. Gómez -- not accepted
  Tithymalus wallichii (Hook. f.) Soják -- not accepted
  Tium drummondii (Douglas ex Hook.) Rydb. -- not accepted
  Tortella fragilis (Hook. & Wils. in Drumm.) Limpr. -- accepted -- fragile tortella moss
  Townsendia Hook. -- not accepted
  Townsendia Hook. -- accepted -- Townsend daisy, townsendia
  Townsendia florifer (Hook.) A. Gray -- accepted -- showy Townsend daisy
  Townsendia florifera (Hook.) A. Gray -- not accepted -- showy Townsend daisy, showy townsendia
  Townsendia sericea Hook. -- not accepted
  Trachycarpus fortunei (Hook.) H. Wendl. -- accepted -- Chinese windmill palm
  Tradescantia virginiana var. alba Hook. ex Raf. -- not accepted
  Trematolobelia macrostachys (Hook. & Arn.) Zahlbr. ex Rock -- accepted -- koli'i
  Triandrophyllum subtrifidum (Hook.f. & Taylor) Fulford & Hatcher -- accepted
  Triandrophyllum subtrifidum var. subtrifidum (Hook.f. & Taylor) Fulford & Hatcher -- accepted
  Trichantha major Hook. -- not accepted
  Trichantha minor Hook. -- not accepted
  Trichipteris phegopteroides (Hook.) R.M. Tryon -- not accepted
  Trichocolea mollissima (Hook.f. & Taylor) Gottsche -- accepted
  Tricholepidozia tetradactyla (Hook.f. & Taylor) E.D. Cooper -- accepted
  Trichomanes krausii Hook. & Grev. -- not accepted -- treemoss bristle fern
  Trichomanes lineolatum (Bosch) Hook. -- not accepted -- lined bristle fern
  Trichosporum javanicum (Hook.) Kuntze -- not accepted
  Trichosporum lobbianum (Hook.) Kuntze -- not accepted
  Trichosporum miniatum var. cordifolium (Hook.) Merr. -- not accepted
  Trichosporum speciosum (Hook.) Kuntze -- not accepted
  Trichosporum tricolor (Hook.) Kuntze -- not accepted
  Trichostomopsis australasiae (Grev. & Hook.) Robins. -- accepted -- Australasia trichostomopsis moss
  Trichostomum tenuirostre (Hook. & Tayl.) Lindb. -- not accepted
  Tricyrtis hirta (Thunb.) Hook. -- accepted -- toadlily
  Trientalis arctica Fisch. ex Hook. -- not accepted
  Trientalis borealis ssp. latifolia (Hook.) Hultén -- not accepted -- broadleaf starflower
  Trientalis europaea ssp. arctica (Fisch. ex Hook.) Hultén -- not accepted -- arctic starflower
  Trientalis europaea var. arctica (Fisch. ex Hook.) Ledeb. -- not accepted
  Trientalis europaea var. latifolia (Hook.) Torr. -- not accepted
  Trientalis latifolia Hook. -- accepted -- broadleaf starflower, western starflower
  Trifolium albopurpureum var. dichotomum (Hook. & Arn.) Isely -- not accepted
  Trifolium chilense Hook. & Arn. -- accepted -- Chilean clover
  Trifolium dichotomum Hook. & Arn. -- accepted -- branched Indian clover
  Trifolium howellii var. latifolium (Hook.) McDermott -- not accepted
  Trifolium latifolium (Hook.) Greene -- accepted -- twin clover
  Trifolium longipes var. latifolium Hook. -- not accepted
  Trifolium macraei Hook. & Arn. -- accepted -- Chilean clover
  Trifolium macraei var. dichotomum (Hook. & Arn.) W.H. Brewer ex S. Watson -- not accepted
  Trifolium melananthum Hook. & Arn. -- not accepted
  Trifolium microdon Hook. & Arn. -- accepted -- thimble clover
  Trifolium obtusiflorum Hook. -- accepted -- clammy clover
  Trifolium spinulosum Douglas ex Hook. -- not accepted
  Trifolium tridentatum var. obtusiflorum (Hook.) S. Watson -- not accepted
  Trifolium variegatum var. melananthum (Hook. & Arn.) Greene -- not accepted
  Trillium chloropetalum var. giganteum (Hook. & Arn.) Munz -- accepted -- giant wakerobin
  Trillium discolor Wray ex Hook. -- accepted -- mottled wakerobin
  Trillium giganteum (Hook. & Arn.) A. Heller -- not accepted
  Trillium sessile ssp. giganteum (Hook. & Arn.) E. Murray -- not accepted
  Trillium sessile var. giganteum Hook. & Arn. -- not accepted
  Trimorpha elata (Hook.) G.L. Nesom -- not accepted
  Trimorpha lonchophylla (Hook.) G.L. Nesom -- not accepted
  Trimorpha lonchophylla var. lonchophylla (Hook.) Nesom -- not accepted -- spearleaf fleabane
  Triodia antarctica Hook. f. -- not accepted
  Tripterocalyx (Torr.) Hook. -- accepted -- sandpuffs
  Tripterocalyx micranthus (Torr.) Hook. -- accepted -- sandpuffs, small-flower sandpuffs, smallflower sand verbena
  Trisetum parvulum (Hook. f.) Speg. -- not accepted
  Triticum dasystachyum (Hook.) A. Gray -- not accepted
  Triticum repens var. dasystachyum Hook. -- not accepted
  Triticum repens var. subvillosum Hook. -- not accepted
  Tritomaria capitata (Hook.) Stotler & Crand.-Stotl. -- not accepted
  Tropidocarpum Hook. -- accepted
  Tropidocarpum gracile Hook. -- accepted -- dobie pod
  Troximon aurantiacum Hook. -- not accepted
  Tulisma verticillata (Hook.) Raf. -- not accepted
  Tumalis bojeri (Hook.) Raf. -- not accepted
  Turritis mollis Hook. -- not accepted
  Tydaea ocellata (Hook.) Regel -- not accepted
  Tydaea picta (Benth. ex Hook.) Decne. -- not accepted
  Ulota drummondii (Hook. & Grev. in Grev.) Brid. -- accepted -- Drummond's ulota moss
  Umbellularia californica (Hook. & Arn.) Nutt. -- accepted -- California laurel
  Umbellularia californica var. californica (Hook. & Arn.) Nutt. -- accepted -- California laurel
  Urostachys phyllanthus (Hook. & Arn.) Herter -- not accepted
  Urtica grandis Hook. & Arn. -- not accepted
  Uvularia smithii Hook. -- not accepted
  Vaccinium corymbosum var. albiflorum (Hook.) Fernald -- not accepted
  Vaccinium membranaceum var. rigidum (Hook.) Fernald -- not accepted
  Vahlodea atropurpurea ssp. latifolia (Hook.) A.E. Porsild -- not accepted
  Vahlodea latifolia (Hook.) Hultén -- not accepted
  Vahlodea magellanica (Hook. f.) Tzvelev -- not accepted
  Vancouveria hexandra (Hook.) C. Morren & Decne. -- accepted -- northern inside-out flower, white insideout flower
  Vanda tricolor Hook. -- not accepted
  Vanhouttea gardneri (Hook.) Fritsch -- accepted
  Vanhouttea gardneri var. gardneri (Hook.) Fritsch -- accepted
  Verbena incisa Hook. -- not accepted
  Verbena venosa Gillies & Hook. -- not accepted
  Verbesina encelioides (Cav.) Benth. & Hook. f. ex A. Gray -- accepted -- golden crownbeard
  Verbesina encelioides ssp. encelioides (Cav.) Benth. & Hook. f. ex A. Gray -- not accepted -- golden crownbeard
  Vesicaria gracilis Hook. -- not accepted
  Viburnum ellipticum Hook. -- accepted -- common viburnum
  Vicia americana ssp. minor (Hook.) Piper & Beattie -- accepted -- mat vetch, purple vetch
  Vicia americana var. minor Hook. -- not accepted -- mat vetch
  Vicia gigantea Hook. -- not accepted
  Vicia kingii Hook. f. -- not accepted
  Vicia magellanica Hook. f. -- accepted
  Vicia nigricans Hook. & Arn. -- accepted -- black vetch
  Vicia nigricans ssp. gigantea (Hook.) Lassetter & C.R. Gunn -- not accepted -- giant vetch
  Vicia nigricans ssp. nigricans Hook. & Arn. -- not accepted -- black vetch
  Vicia nigricans var. gigantea (Hook.) Broich -- accepted -- giant vetch
  Vicia nigricans var. nigricans Hook. & Arn. -- accepted -- black vetch
  Vicia tetrasperma var. gracilis (Hook.) Asch. & Graebn. -- not accepted
  Vigna nilotica (Delile) Hook. f. -- not accepted
  Vilfa cuspidata Torr. ex Hook. -- not accepted
  Vilfa depauperata Torr. ex Hook. -- not accepted
  Vilfa tenacissima var. fuscicolor Hook. -- not accepted
  Viola adunca var. minor (Hook.) Fernald -- not accepted
  Viola nuttallii var. major Hook. -- not accepted
  Viola porterana var. major (Hook.) M.S. Baker -- not accepted
  Viola praemorsa ssp. major (Hook.) M.S. Baker ex M. Peck -- not accepted
  Viola praemorsa var. major (Hook.) M. Peck -- not accepted
  Viola sarmentosa Douglas ex Hook. -- not accepted
  Viola vallicola var. major (Hook.) Fabijan -- accepted -- valley violet
  Virgulus patens var. gracilis (Hook.) Reveal & Keener -- not accepted
  Voyria tenella Hook. -- accepted -- Puerto Rico ghostplant
  Wahlbergella drummondii (Hook.) Rydb. -- not accepted
  Wardia Harv. & Hook. -- accepted
  Weissia rostellata var. phascoides (Hook. & Drumm.) Reese & Lemmon -- not accepted
  Welwitschia Hook. f. -- accepted
  Welwitschia mirabilis Hook. f. -- accepted
  Whitia carnosa Benth. & Hook. f. -- not accepted
  Woodsia oregana var. lyallii (Hook.) B. Boivin -- not accepted
  Wyethia scabra Hook. -- not accepted -- badlands mule-ears, badlands mulesears, badlands wyethia
  Wyethia scabra var. scabra Hook. -- not accepted -- badlands mule-ears, badlands mulesears
  X Cyathidaria wilsonii (Hook.) Caluff & Shelton -- not accepted
  Xanthium ambrosioides Hook. & Arn. -- not accepted -- cocklebur
  Xanthocephalum gymnospermoides (A. Gray) Benth. & Hook. f. -- accepted -- matchweed, San Pedro matchweed
  Yabea microcarpa (Hook. & Arn.) Koso-Pol. -- accepted -- false carrot, false hedge-parsley, falsecarrot
  Zantedeschia albomaculata (Hook.) Baill. -- accepted -- spotted calla lily
  Zauschneria californica ssp. latifolia (Hook.) D.D. Keck -- not accepted
  Zauschneria latifolia (Hook.) Greene -- not accepted
  Zeia dasystachyum (Hook.) Lunell -- not accepted
  Zeltnera texensis (Griseb. ex Hook.) G. Mans. -- not accepted
  Zerna vulgaris (Hook.) Henrard -- not accepted
  Zigadenus fremontii var. minor (Hook. & Arn.) Jeps. -- not accepted
  Ziziphus obtusifolia (Hook. ex Torr. & A. Gray) A. Gray -- accepted -- graythorn, Lote bush, lotebush
  Ziziphus obtusifolia var. obtusifolia (Hook. ex Torr. & A. Gray) A. Gray -- accepted -- graythorn, lotebush
  Zoopsis Hook.f. ex Gottsche -- accepted
  Zoopsis argentea (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Zoopsis argentea var. argentea (Hook.f. & Taylor) Gottsche, Lindenb. & Nees -- accepted
  Zygodon Hook. & Tayl. -- accepted -- zygodon moss
  Zygodon conoideus (Dicks.) Hook. & Tayl. -- accepted -- zygodon moss
 
 Kingdom Bacteria
  Angiococcus (ex Jahn, 1924) Hook et al., 1980 -- valid
  Angiococcus disciformis (Thaxter, 1904) Hook et al., 1980 -- valid
  Legionella lytica (Drozanski, 1991) Hookey et al., 1996 -- valid
  Lyngbya purpurea (Hooker and Harvey) Gomont -- valid
   

A gray bar