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Taxon author: Howell

ITIS records citing taxon author "Howell"
 
 Kingdom Animalia
  Agelaius phoeniceus grinnelli A. B. Howell, 1917 -- valid
  Agelaius phoeniceus littoralis A. H. Howell & Van Rossem, 1928 -- valid
  Agelaius phoeniceus mearnsi A. H. Howell & Van Rossem, 1928 -- valid
  Aimophila botterii spadiconigrescens T. R. Howell, 1965 -- invalid
  Amazilia cyanocephala chlorostephana T. R. Howell, 1965 -- valid
  Amazona auropalliata parvipes B. L. Monroe Jr & T. R. Howell, 1966 -- valid
  Amazona oratrix belizensis B. L. Monroe Jr & T. R. Howell, 1966 -- valid
  Ammodramus maritimus mirabilis (A. H. Howell, 1919) -- valid -- Cape Sable Seaside Sparrow
  Ammospermophilus leucurus pennipes A. H. Howell, 1931 -- valid
  Ammospiza maritima mirabilis (A. H. Howell, 1919) -- invalid
  Arthroleptides yakusini Channing, Moyer and Howell, 2002 -- invalid
  Atheris matildae Menegon, Davenport and Howell, 2011 -- valid -- Matilda's Horned Viper
  Callospermophilus lateralis caryi A. H. Howell, 1917 -- invalid
  Callospermophilus lateralis connectens (A. H. Howell, 1931) -- valid
  Callospermophilus lateralis mitratus (A. H. Howell, 1931) -- valid
  Caulolatilus intermedius Howell Rivero, 1936 -- valid -- anchor tilefish, blanquillo payaso, tumba parda
  Chimaera cubana Howell Rivero, 1936 -- valid -- chimaera, Cuban chimaera, quimera
  Corvus brachyrhynchos paulus Howell, 1913 -- invalid
  Cyprinella gibbsi (Howell and Williams, 1971) -- valid -- Tallapoosa shiner
  Dendroica discolor paludicola A. H. Howell, 1930 -- invalid
  Eoglaucomys A. H. Howell, 1915 -- valid
  Etheostoma neopterum Howell and Dingerkus, 1978 -- valid -- lollipop darter, lollypop darter
  Etheostoma nuchale Howell and Caldwell, 1965 -- valid -- watercress darter
  Euchoreutes naso alashanicus A. B. Howell, 1928 -- invalid
  Falco sparverius nicaraguensis T. R. Howell, 1965 -- valid
  Glaucidium parkeri Robbins & S. N. G. Howell, 1995 -- valid -- Subtropical Pygmy Owl
  Glaucomys sabrinus bullatus A. H. Howell, 1915 -- invalid
  Glaucomys sabrinus canescens A. H. Howell, 1915 -- valid
  Glaucomys sabrinus columbiensis A. H. Howell, 1915 -- valid -- Okanagan flying squirrel
  Glaucomys sabrinus flaviventris A. H. Howell, 1915 -- valid -- yellow-bellied flying squirrel
  Glaucomys sabrinus griseifrons A. H. Howell, 1934 -- valid -- Prince of Wales flying squirrel, Prince of Wales Island flying squirrel
  Glaucomys sabrinus latipes A. H. Howell, 1915 -- valid -- broad-footed flying squirrel
  Glaucomys volans saturatus A. H. Howell, 1915 -- valid -- southeastern flying squirrel
  Glaucomys volans texensis A. H. Howell, 1915 -- valid -- Texas flying squirrel
  Ictidomys tridecemlineatus arenicola (A. H. Howell, 1928) -- valid
  Ictidomys tridecemlineatus monticola (A. H. Howell, 1928) -- valid -- White Mountains ground squirrel
  Ijimaia antillarum Howell Rivero, 1935 -- valid -- jellynose
  Ijimaia fowleri Howell Rivero, 1935 -- valid
  Kassina jozani Msuya, Howell and Channing, 2007 -- valid
  Kinyongia msuyae Menegon, Loader, Davenport, Howell, Tilbury, Machaga and Tolley, 2015 -- valid
  Labrisomus nigricinctus Howell Rivero, 1936 -- valid -- sapito lunado, spotcheek blenny, trambollo lunado
  Loligo hemiptera Howell, 1867 -- invalid
  Marmota caligata cascadensis A. H. Howell, 1914 -- valid
  Marmota caligata nivaria Howell, 1914 -- invalid
  Marmota caligata sheldoni A. H. Howell, 1914 -- invalid -- Montague Island hoary marmot
  Marmota flaviventris luteola A. H. Howell, 1914 -- valid
  Marmota flaviventris nosophora A. H. Howell, 1914 -- valid
  Marmota flaviventris obscura A. H. Howell, 1914 -- valid
  Marmota flaviventris parvula A. H. Howell, 1915 -- valid
  Marmota flaviventris sierrae A. H. Howell, 1915 -- valid
  Marmota monax petrensis A. H. Howell, 1915 -- valid
  Marmota monax preblorum A. H. Howell, 1914 -- valid
  Marmota monax pretensis A. H. Howell, 1915 -- invalid
  Marmota monax rufescens A. H. Howell, 1914 -- valid
  Mephitis mephitis major (Howell, 1901) -- valid
  Mephitis mephitis notata (Howell, 1901) -- valid
  Microtus mordax abditus A. B. Howell, 1923 -- invalid
  Microtus parvulus (A. H. Howell, 1916) -- invalid
  Microtus pinetorum parvulus (A. H. Howell, 1916) -- invalid
  Mustela frenata olivacea Howell, 1913 -- valid
  Mustela peninsulae olivacea Howell, 1913 -- invalid
  Myotis grisescens A. H. Howell, 1909 -- valid -- gray bat, gray myotis, Gray Myotis
  Myotis siligorensis sowerbyi Howell, 1926 -- valid
  Myotis sowerbyi Howell, 1926 -- invalid
  Nectophrynoides asperginis Poynton, Howell, Clarke and Lovett, 1999 -- valid
  Neofiber alleni nigrescens A. H. Howell, 1920 -- invalid
  Neotamias A. H. Howell, 1929 -- invalid
  Neotoma floridana haematoreia A. H. Howell, 1934 -- invalid
  Neotoma floridana illinoensis A. H. Howell, 1910 -- invalid
  Notocitellus A. H. Howell, 1938 -- valid -- tropical ground squirrels
  Notropis gibbsi Howell and Williams, 1971 -- invalid -- Tallapoosa shiner
  Ochotona argentata Howell, 1928 -- valid -- Silver Pika
  Ochotona princeps goldmani Howell, 1924 -- invalid
  Ochotona princeps nevadensis Howell, 1919 -- invalid
  Octopus filosa Howell, 1867 -- invalid
  Octopus filosus Howell, 1867 -- valid
  Otospermophilus beecheyi parvulus (A. H. Howell, 1931) -- valid
  Otospermophilus beecheyi sierrae (A. H. Howell, 1938) -- valid
  Peromyscus gossypinus restrictus A. H. Howell, 1939 -- invalid
  Peromyscus leucocephalus A. H. Howell, 1920 -- invalid
  Peromyscus nuttalli lewisi A. H. Howell, 1939 -- invalid
  Peromyscus polionotus decoloratus A. H. Howell, 1939 -- invalid
  Peromyscus polionotus leucocephalus A. H. Howell, 1920 -- invalid
  Peromyscus polionotus peninsularis A. H. Howell, 1939 -- invalid -- St. Andrew beach mouse
  Petaurista philippensis rubricundus A. B. Howell, 1927 -- valid
  Petropedetes yakusini (Channing, Moyer and Howell, 2002) -- valid
  Peucaea botterii spadiconigrescens (T. R. Howell, 1965) -- valid
  Phenacomys intermedius celsus A. B. Howell, 1923 -- invalid
  Phenacomys intermedius levis A. B. Howell, 1923 -- invalid
  Phenacomys silvicolus A. B. Howell, 1921 -- invalid
  Phrynobatrachus uzungwensis Grandison and Howell, 1984 -- valid
  Pipilo erythrophthalmus canaster A. H. Howell, 1913 -- valid
  Piranga flava savannarum T. R. Howell, 1965 -- invalid
  Piranga hepatica savannarum T. R. Howell, 1965 -- valid
  Pitymys parvulus A. H. Howell, 1916 -- invalid
  Poliocitellus A. H. Howell, 1938 -- valid -- Franklin's ground squirrel
  Pseudothrips beckhami Beshear and Howell, 1976 -- valid
  Pyrocephalus rubinus pinicola T. R. Howell, 1965 -- valid
  Rattus humiliatus insolatus A. B. Howell, 1927 -- invalid
  Rattus humiliatus sowerbyi A. B. Howell, 1928 -- invalid
  Rattus rattus exiguus A. B. Howell, 1927 -- invalid
  Reithrodontomys (Aporodon) A. H. Howell, 1914 -- valid
  Reithrodontomys alleni A. H. Howell, 1914 -- invalid
  Reithrodontomys amoles A. H. Howell, 1914 -- invalid
  Reithrodontomys fulvescens chiapensis A. H. Howell, 1914 -- invalid
  Reithrodontomys fulvescens mustelinus A. H. Howell, 1914 -- invalid
  Reithrodontomys fulvescens nelsoni A. H. Howell, 1914 -- invalid
  Reithrodontomys humulis virginianus A. H. Howell, 1940 -- invalid
  Reithrodontomys mexicanus lucifrons A. H. Howell, 1932 -- invalid
  Reithrodontomys mexicanus minusculus A. H. Howell, 1932 -- invalid
  Reithrodontomys rufescens luteolus A. H. Howell, 1914 -- invalid
  Rhinolophus maendeleo Kock, Csorba and Howell, 2000 -- valid -- Maendeleo Horseshoe Bat
  Scalopus aquaticus bassi Howell, 1939 -- valid -- Englewood mole
  Sciurus niger avicennia A. H. Howell, 1919 -- valid -- Big Cypress fox squirrel
  Sciurus niger avicinnia A. H. Howell, 1919 -- invalid
  Scotinomys teguina stenopygius Buchanan and T. R. Howell, 1967 -- invalid
  Scyliorhinus torrei Howell Rivero, 1936 -- valid -- dwarf cat shark, dwarf catshark, gatica prieta
  Setophaga discolor paludicola (A. H. Howell, 1930) -- valid
  Sialia sialis caribaea T. R. Howell, 1965 -- valid
  Sigmodon hispidus cienegae A. B. Howell, 1919 -- invalid
  Sigmodon hispidus floridanus A. H. Howell, 1943 -- invalid
  Sigmodon hispidus insulicola A. H. Howell, 1943 -- invalid
  Spermophilus brunneus (A. H. Howell, 1928) -- invalid -- Idaho Ground Squirrel, northern Idaho ground squirrel
  Spermophilus brunneus brunneus (A. H. Howell, 1928) -- invalid -- northern Idaho ground squirrel
  Spermophilus elegans nevadensis (A. H. Howell, 1928) -- invalid
  Spermophilus tridecemlineatus monticola (A. H. Howell, 1928) -- invalid
  Spermophilus washingtoni (A. H. Howell, 1938) -- invalid -- Washington Ground Squirrel
  Spermophilus washingtoni loringi (A. H. Howell, 1938) -- invalid
  Spilogale angustifrons Howell, 1902 -- valid -- Southern Spotted Skunk
  Spilogale angustifrons angustifrons Howell, 1902 -- valid
  Spilogale angustifrons elata Howell, 1906 -- valid
  Spilogale angustifrons tropicalis Howell, 1902 -- valid
  Squalus cubensis Howell Rivero, 1936 -- valid -- cazón aguijón cubano, Cuban dogfish, galludo cubano
  Squalus tasmaniensis Howell Rivero, 1936 -- invalid
  Tamias (Neotamias) A. H. Howell, 1929 -- valid
  Tamias amoenus ochraceus (A. H. Howell, 1925) -- valid
  Tamias amoenus vallicola (A. H. Howell, 1922) -- valid
  Tamias durangae solivagus (A. H. Howell, 1922) -- valid
  Tamias minimus arizonensis (A. H. Howell, 1922) -- valid
  Tamias minimus confinis (A. H. Howell, 1925) -- valid
  Tamias minimus grisescens (A. H. Howell, 1925) -- valid
  Tamias minimus jacksoni (A. H. Howell, 1925) -- valid
  Tamias ruficaudus (A. H. Howell, 1920) -- valid -- Red-tailed Chipmunk
  Tamias ruficaudus ruficaudus (A. H. Howell, 1920) -- valid
  Tamias ruficaudus simulans (A. H. Howell, 1922) -- valid
  Tamias sibiricus umbrosus (A. H. Howell, 1927) -- valid
  Tamias siskiyou (A. H. Howell, 1922) -- valid -- Siskiyou Chipmunk
  Tamias siskiyou siskiyou (A. H. Howell, 1922) -- valid
  Tamias sonomae alleni (A. H. Howell, 1922) -- valid
  Tamias speciosus sequoiensis (A. H. Howell, 1922) -- valid
  Tamias striatus fisheri A. H. Howell, 1925 -- valid
  Tamiasciurus hudsonicus abieticola (A. H. Howell, 1929) -- valid
  Tamiasciurus hudsonicus columbiensis A. H. Howell, 1936 -- valid
  Tamiasciurus hudsonicus kenaiensis A. H. Howell, 1936 -- valid
  Tamiasciurus hudsonicus pallescens A. H. Howell, 1942 -- valid
  Tamiasciurus hudsonicus preblei A. H. Howell, 1936 -- valid
  Tamiasciurus hudsonicus regalis A. H. Howell, 1936 -- valid
  Urocitellus brunneus (A. H. Howell, 1928) -- valid -- Idaho Ground Squirrel
  Urocitellus brunneus brunneus (A. H. Howell, 1928) -- valid -- northern Idaho ground squirrel
  Urocitellus columbianus ruficaudus (A. H. Howell, 1928) -- valid
  Urocitellus elegans nevadensis (A. H. Howell, 1928) -- valid
  Urocitellus washingtoni (A. H. Howell, 1938) -- valid -- Washington Ground Squirrel
  Wadotes georgiensis Howell, 1974 -- valid
  Xerospermophilus spilosoma pallescens (A. H. Howell, 1928) -- valid
  Zapus trinotatus eureka A. B. Howell, 1920 -- invalid
 
 Kingdom Plantae
  Achillea borealis var. arenicola (A. Heller) J.T. Howell -- not accepted
  Achillea borealis var. californica (Pollard) J.T. Howell -- not accepted
  Aconitum bulbiferum Howell -- not accepted
  Agrostis longiligula var. australis J.T. Howell -- not accepted -- longtongue bentgrass
  Allium watsonii Howell -- not accepted
  Allocarya bracteata Howell -- not accepted
  Alsine brachypetala (Bong.) Howell -- not accepted
  Alsine simcoei Howell -- not accepted
  Ambrosia chamissonis var. bipinnatisecta (Less.) J.T. Howell -- not accepted
  Arabis arcuata var. secunda (Howell) B.L. Rob. -- not accepted
  Arabis holboellii var. secunda (Howell) Jeps. -- not accepted
  Arabis koehleri Howell -- not accepted -- Koehler's rockcress
  Arabis koehleri var. koehleri Howell -- not accepted -- Koehler's rockcress
  Arabis purpurascens Howell ex Greene -- not accepted
  Arabis secunda Howell -- not accepted
  Arctostaphylos bracteata Howell -- not accepted
  Arctostaphylos edmundsii J.T. Howell -- accepted -- Little Sur manzanita
  Arctostaphylos glauca var. puberula J.T. Howell -- not accepted
  Arctostaphylos hispidula Howell -- accepted -- Gasquet manzanita
  Arctostaphylos intricata Howell -- not accepted
  Arctostaphylos intricata var. oblongifolia (Howell) Munz -- not accepted
  Arctostaphylos oblongifolia Howell -- not accepted
  Arctostaphylos puchella Howell -- not accepted
  Arctostaphylos pulchella Howell -- not accepted
  Arctostaphylos pungens ssp. hispidula (Howell) Roof -- not accepted
  Arctostaphylos stanfordiana ssp. hispidula (Howell) J.E. Adams -- not accepted
  Arctostaphylos strigosa Howell -- not accepted
  Arctostaphylos uva-ursi ssp. emundsii (J.T. Howell) Roof -- not accepted
  Arctostaphylos viscida ssp. pulchella (Howell) P.V. Wells -- accepted -- serpentine manzanita, sticky whiteleaf manzanita
  Arctostaphylos X cinerea Howell (pro sp.) -- accepted -- Waldo manzanita
  Arctostaphylos X parvifolia Howell (pro sp.) -- accepted -- gravel manzanita
  Arctostaphylos X repens (J.T. Howell) P.V. Wells -- accepted -- PMC manzanita
  Arenaria burkei Howell -- not accepted
  Arnica cernua Howell -- accepted -- serpentine arnica
  Aster attenuatus (Howell) M. Peck non Lindl. ex Hook. -- not accepted
  Aster eatonii (A. Gray) Howell -- not accepted -- Eaton's aster
  Aster geyeri (A. Gray) Howell -- not accepted
  Astragalus hoodianus Howell -- accepted -- Hood River milkvetch
  Astragalus lentiginosus var. salinus (Howell) Barneby -- accepted -- salty loco milkvetch
  Astragalus nuttallii (Torr. & A. Gray) J.T. Howell -- accepted -- Nuttall's milkvetch
  Astragalus nuttallii var. nuttallii (Torr. & A. Gray) J.T. Howell -- accepted -- Nuttall's milkvetch
  Astragalus pulsiferae var. suksdorfii (Howell) Barneby -- accepted -- Suksdorf's milkvetch
  Astragalus salinus Howell -- not accepted
  Baeria bakeri J.T. Howell -- not accepted
  Baeria macrantha var. bakeri (J.T. Howell) D.D. Keck -- not accepted
  Baeria macrantha var. thalassophila J.T. Howell -- not accepted
  Betula glandulosa var. hallii (Howell) C.L. Hitchc. -- not accepted
  Blennosperma nanum var. robustum J.T. Howell -- accepted -- common stickyseed
  Boechera holboellii var. secunda (Howell) Dorn -- not accepted
  Boechera koehleri (Howell) Al-Shehbaz -- accepted -- Koehler's rockcress
  Calamagrostis ophitidis (J.T. Howell) Nygren -- accepted -- serpentine reedgrass
  Calamagrostis purpurascens var. ophitidis J.T. Howell -- not accepted
  Calandrinia ambigua (S. Watson) Howell -- not accepted
  Calochortus superbus Purdy ex J.T. Howell -- accepted -- yellow mariposa
  Calyptridium parryi ssp. nevadense (J.T. Howell) Munz -- not accepted
  Calyptridium parryi var. arizonicum J.T. Howell -- not accepted
  Calyptridium parryi var. nevadense J.T. Howell -- not accepted
  Camassia quamash var. linearis (Gould) J.T. Howell -- not accepted
  Campanula angustiflora var. exilis J.T. Howell -- not accepted
  Campanula piperi Howell -- accepted -- Olympic bellflower, Olympic harebell
  Cardamine occidentalis (S. Watson) Howell -- accepted -- big western bittercress
  Carex jepsonii J.T. Howell -- not accepted
  Carex specuicola J.T. Howell -- accepted -- Navajo sedge
  Carex tompkinsii J.T. Howell -- accepted -- Thompkins' sedge
  Castilleja leschkeana J.T. Howell -- not accepted -- Point Reyes paintbrush
  Caulanthus amplexicaulis var. barbarae (J.T. Howell) Munz -- not accepted -- claspingleaf wild cabbage, Santa Barbara jewelflower
  Ceanothus confusus J.T. Howell -- accepted -- Rincon ceanothus, Rincon Ridge ceanothus
  Ceanothus cuneatus ssp. sonomensis (J.T. Howell) C.L. Schmidt -- not accepted -- Sonoma ceanothus
  Ceanothus cuneatus var. dubius J.T. Howell -- not accepted
  Ceanothus divergens ssp. confusus (J.T. Howell) Abrams -- not accepted
  Ceanothus gloriosus J.T. Howell -- accepted -- Point Reyes ceanothus
  Ceanothus gloriosus ssp. exaltatus (J.T. Howell) C.L. Schmidt -- not accepted -- Point Reyes ceanothus
  Ceanothus gloriosus ssp. gloriosus J.T. Howell -- not accepted -- Point Reyes creeper
  Ceanothus gloriosus ssp. porrectus (J.T. Howell) C.L. Schmidt -- not accepted -- Point Reyes creeper
  Ceanothus gloriosus var. exaltatus J.T. Howell -- accepted -- Point Reyes ceanothus
  Ceanothus gloriosus var. gloriosus J.T. Howell -- accepted -- Point Reyes ceanothus
  Ceanothus gloriosus var. porrectus J.T. Howell -- accepted -- Mount Vision ceanothus, Mt. Vision ceanothus
  Ceanothus jepsonii ssp. albiflorus (J.T. Howell) C.L. Schmidt -- not accepted -- Jepson ceanothus
  Ceanothus jepsonii var. albiflorus J.T. Howell -- accepted -- Jepson ceanothus
  Ceanothus prostratus ssp. confusus (J.T. Howell) C.L. Schmidt -- not accepted -- squawcarpet
  Ceanothus sonomensis J.T. Howell -- accepted -- Sonoma ceanothus
  Centrostegia thurberi var. macrotheca (J.T. Howell) Goodman -- not accepted
  Ceratoides lanata (Pursh) J.T. Howell -- not accepted
  Ceratoides lanata var. subspinosa (Rydb.) J.T. Howell -- not accepted
  Chenopodium ambrosioides var. vagans (Standl.) J.T. Howell -- not accepted
  Chenopodium macrospermum var. farinosum (S. Watson) J.T. Howell -- not accepted -- largeseed goosefoot
  Chorizanthe thurberi var. macrotheca J.T. Howell -- not accepted
  Cirsium callilepis var. oregonense (Petr.) J.T. Howell -- not accepted
  Cirsium callilepis var. pseudocarlinoides (Petr.) J.T. Howell -- not accepted
  Cirsium ciliolatum (L.F. Hend.) J.T. Howell -- accepted -- Ashland thistle
  Cirsium cymosum (Greene) J.T. Howell -- accepted -- peregrine thistle
  Cirsium cymosum var. cymosum (Greene) J.T. Howell -- accepted -- peregrine thistle
  Cirsium douglasii var. canescens (Petr.) J.T. Howell -- not accepted
  Cirsium fontinale var. obispoense J.T. Howell -- accepted -- Chorro Creek bog thistle
  Cirsium hydrophilum var. vaseyi (A. Gray) J.T. Howell -- accepted -- Vasey's thistle
  Cirsium pastoris J.T. Howell -- not accepted -- snowy thistle
  Cirsium proteanum J.T. Howell -- not accepted
  Cistanthe parryi var. arizonica (J.T. Howell) Kartesz & Gandhi -- not accepted -- Arizona pussypaws
  Cistanthe parryi var. nevadensis (J.T. Howell) Kartesz & Gandhi -- not accepted -- Nevada pussypaws
  Claytonia rubra (Howell) Tidestr. -- accepted -- red-stem springbeauty, redstem springbeauty
  Claytonia rubra ssp. rubra (Howell) Tidestr. -- accepted -- redstem springbeauty
  Clematis brevifolia Howell -- not accepted
  Collinsia rattanii ssp. glandulosa (Howell) Pennell -- accepted -- sticky blue eyed Mary
  Convolvulus occidentalis ssp. saxicola (Eastw.) J.T. Howell -- not accepted
  Convolvulus occidentalis var. purpuratus (Greene) J.T. Howell -- not accepted
  Convolvulus occidentalis var. saxicola (Eastw.) J.T. Howell -- not accepted
  Convolvulus occidentalis var. solanensis (Jeps.) J.T. Howell -- not accepted
  Cordylanthus nidularius J.T. Howell -- accepted -- Mount Diablo bird's-beak
  Cordylanthus tenuis ssp. viscidus (Howell) T.I. Chuang & Heckard -- accepted -- slender bird's beak
  Cordylanthus viscidus (Howell) Pennell ex M. Peck -- not accepted
  Crataegus columbiana Howell -- not accepted -- Columbia hawthorn
  Crataegus columbiana var. columbiana Howell -- not accepted -- Columbian hawthorn
  Crepis runcinata ssp. hispidulosa (Howell ex Rydb.) Babc. & Stebbins -- accepted -- fiddleleaf hawksbeard
  Crepis runcinata var. hispidulosa Howell ex Rydb. -- not accepted
  Cryptantha circumscissa ssp. rosulata (J.T. Howell) Mathew & P.H. Raven -- not accepted
  Cryptantha circumscissa var. rosulata J.T. Howell -- accepted -- cushion cryptantha
  Dedeckera Reveal & J.T. Howell -- accepted -- July gold, Mary's grass
  Dedeckera eurekensis Reveal & J.T. Howell -- accepted -- July gold
  Delphinium oreganum Howell -- not accepted
  Dentaria gemmata (Greene) Howell -- not accepted
  Dentaria tenella var. quercetorum (Howell) Detling -- not accepted
  Eleocharis quinqueflora var. suksdorfiana (Beauverd) J.T. Howell -- not accepted
  Epilobium paniculatum var. hammondii (Howell) M. Peck -- not accepted
  Ericameria ophitidis (J.T. Howell) G.L. Nesom -- accepted -- serpentine goldenbush
  Erigeron aliceae Howell -- accepted -- Alice Eastwood's fleabane
  Erigeron foliosus var. confinis (Howell) Jeps. -- accepted -- leafy fleabane
  Erigeron linearis var. elegantulus (Greene) J.T. Howell -- not accepted
  Eriogonum ampullaceum J.T. Howell -- accepted -- Mono buckwheat
  Eriogonum apricum J.T. Howell -- accepted -- Ione buckwheat
  Eriogonum apricum var. apricum J.T. Howell -- accepted -- Ione buckwheat
  Eriogonum argillosum J.T. Howell -- accepted -- clay buckwheat
  Eriogonum breedlovei (J.T. Howell) Reveal -- accepted -- Paiute buckwheat, Piute buckwheat
  Eriogonum breedlovei var. breedlovei (J.T. Howell) Reveal -- accepted -- Paiute buckwheat, Piute buckwheat
  Eriogonum breedlovei var. shevockii J.T. Howell -- accepted -- Needle's buckwheat, The Needles buckwheat
  Eriogonum butterworthianum J.T. Howell -- accepted -- Butterworth's buckwheat
  Eriogonum carneum (J.T. Howell) Reveal -- not accepted
  Eriogonum eastwoodianum J.T. Howell -- accepted -- Eastwood's buckwheat
  Eriogonum eremicola J.T. Howell & Reveal -- accepted -- Telescope Peak buckwheat, Wild Rose Canyon buckwheat
  Eriogonum esmeraldense var. toiyabense J.T. Howell -- accepted -- Toiyabe buckwheat
  Eriogonum glandulosum var. carneum J.T. Howell -- not accepted
  Eriogonum hirtellum J.T. Howell & Bacig. -- accepted -- Klamath Mountain buckwheat, Klamath Mountain wild buckwheat
  Eriogonum mohavense ssp. ampullaceum (J.T. Howell) S. Stokes -- not accepted
  Eriogonum nudum var. westonii (S. Stokes) J.T. Howell -- accepted -- Weston's buckwheat
  Eriogonum ochrocephalum var. breedlovei J.T. Howell -- not accepted
  Eriogonum ochrocephalum var. gracilipes (S. Watson) J.T. Howell -- not accepted
  Eriogonum ovalifolium var. eximium (Tidestr.) J.T. Howell -- accepted -- brownmargin buckwheat, cushion buckwheat
  Eriogonum parvifolium ssp. lucidum J.T. Howell ex S. Stokes -- not accepted
  Eriogonum parvifolium var. lucidum (J.T. Howell ex S. Stokes) Reveal -- not accepted -- Point Lobos wild buckwheat
  Eriogonum racemosum var. coccineum (J.T. Howell) S.L. Welsh -- not accepted
  Eriogonum racemosum var. zionis (J.T. Howell) S.L. Welsh -- not accepted
  Eriogonum ripleyi J.T. Howell -- accepted -- Fraziers Well buckwheat, Ripley wild-buckwheat
  Eriogonum spergulinum var. pratense (S. Stokes) J.T. Howell -- accepted -- spurry buckwheat
  Eriogonum spergulinum var. reddingianum (M.E. Jones) J.T. Howell -- accepted -- Redding buckwheat
  Eriogonum temblorense J.T. Howell & Twisselm. -- accepted -- Temblor buckwheat
  Eriogonum ternatum Howell -- accepted -- ternate buckwheat
  Eriogonum ternatum var. congdonii (S. Stokes) J.T. Howell -- not accepted
  Eriogonum twisselmannii (J.T. Howell) Reveal -- accepted -- Twisselmann's buckwheat
  Eriogonum vestitum J.T. Howell -- accepted -- Idria buckwheat
  Eriogonum viscidulum J.T. Howell -- accepted -- clammy buckwheat, sticky buckwheat
  Eriogonum wrightii var. olanchense (J.T. Howell) Reveal -- accepted -- Olancha Peak buckwheat
  Eriogonum zionis J.T. Howell -- accepted -- Zion buckwheat, Zion wild buckwheat
  Eriogonum zionis var. coccineum J.T. Howell -- accepted -- Zion buckwheat
  Eriogonum zionis var. zionis J.T. Howell -- accepted -- Zion buckwheat
  Eriophyllum lanatum var. aphanactis J.T. Howell -- not accepted -- common woolly sunflower
  Eriophyllum lanatum var. lanceolatum (Howell) Jeps. -- accepted -- common woolly sunflower
  Erodium obtusiplicatum (Maire, Weiller & Wilczek) J.T. Howell -- not accepted
  Erysimum capitatum var. stellatum (J.T. Howell) Twisselm. -- not accepted
  Erythronium grandiflorum ssp. pusaterii Munz & J.T. Howell -- not accepted -- Kaweah fawn lily
  Erythronium pusaterii (Munz & J.T. Howell) Shevock, Bartel & G.A. Allen -- accepted -- Kaweah Lakes fawnlily
  Eschscholzia frutescens (Greene) J.T. Howell -- not accepted
  Euphorbia bisulcata J.T. Howell -- not accepted
  Euphorbia guadalupensis J.T. Howell -- not accepted
  Euphorbia ocellata var. kirbyi J.T. Howell -- not accepted
  Euphorbia patellifera J.T. Howell -- not accepted
  Euphorbia pseudoserpyllifolia f. typica J.T. Howell -- not accepted
  Euphorbia pseudoserpyllifolia f. villosa J.T. Howell -- not accepted
  Euphorbia vallis-mortae (Millsp.) J.T. Howell -- accepted -- Death Valley sandmat
  Festuca ovina var. minutiflora (Rydb.) J.T. Howell -- not accepted
  Filipendula occidentalis (S. Watson) Howell -- accepted -- queen of the forest, queen-of-the-forest
  Fragaria cuneifolia Nutt. ex Howell -- not accepted
  Fragaria X ananassa ssp. cuneifolia (Nutt. ex Howell) Staudt (pro nm.) -- accepted
  Fragaria X ananassa var. cuneifolia (Nutt. ex Howell) Staudt -- not accepted -- hybrid strawberry
  Frangula californica ssp. occidentalis (Howell) Kartesz & Gandhi -- not accepted -- California buckthorn
  Galium angustifolium ssp. foliosum (Hilend & J.T. Howell) Dempster & Stebbins -- accepted -- narrowleaf bedstraw
  Galium angustifolium var. bernardinum Hilend & J.T. Howell -- not accepted
  Galium angustifolium var. diffusum Hilend & J.T. Howell -- not accepted
  Galium angustifolium var. foliosum Hilend & J.T. Howell -- not accepted
  Galium angustifolium var. siccatum (W. Wight) Hilend & J.T. Howell -- not accepted
  Galium angustifolium var. typicum Hilend & J.T. Howell -- not accepted
  Galium californicum var. typicum Hilend & J.T. Howell -- not accepted
  Galium collomae J.T. Howell -- not accepted
  Galium collomiae J.T. Howell -- accepted -- Fossil Hill Creek bedstraw
  Galium hilendiae ssp. carneum (Hilend & J.T. Howell) Dempster & Ehrend. -- accepted -- Hilend's bedstraw, Panamint Mountains bedstraw
  Galium hypotrichium ssp. subalpinum (Hilend & J.T. Howell) Ehrend. -- accepted -- subalpine bedstraw
  Galium jepsonii Hilend & J.T. Howell -- accepted -- Jepson's bedstraw
  Galium multiflorum var. subalpinum (Hilend & J.T. Howell) Cronquist -- not accepted
  Galium munzii Hilend & J.T. Howell -- accepted -- Munz's bedstraw
  Galium munzii ssp. munzii Hilend & J.T. Howell -- accepted -- Munz's bedstraw
  Galium munzii var. carneum Hilend & J.T. Howell -- not accepted
  Galium munzii var. minzii Hilend & J.T. Howell -- not accepted
  Galium munzii var. subalpinum Hilend & J.T. Howell -- not accepted
  Galium parishii Hilend & J.T. Howell -- accepted -- Parish's bedstraw
  Galium stellatum ssp. eremicum (Hilend & J.T. Howell) Ehrend. -- accepted -- desert bedstraw, starry bedstraw
  Galium stellatum var. eremicum Hilend & J.T. Howell -- not accepted
  Gentiana bisetaea Howell -- not accepted
  Geranium oreganum Howell -- accepted -- Oregon geranium
  Grindelia camporum var. bracteosa (J.T. Howell) M.A. Lane -- not accepted -- bract gumweed
  Grindelia robusta var. bracteosa (J.T. Howell) D.D. Keck -- not accepted
  Hackelia amethystima J.T. Howell -- not accepted
  Hackelia amethystina J.T. Howell -- accepted -- amethyst stickseed
  Haplopappus bloomeri var. ophitidis J.T. Howell -- not accepted
  Haplopappus ophitidis (J.T. Howell) D.D. Keck -- not accepted
  Haplopappus ophitidus (J. T. Howell) D.D. Keck -- not accepted
  Haplopappus peirsonii (D.D. Keck) J.T. Howell -- not accepted
  Haplopappus whitneyi ssp. discoideus (J.T. Howell) D.D. Keck -- not accepted
  Hazardia whitneyi var. discoidea (J.T. Howell) W.D. Clark -- accepted -- Whitney's bristleweed
  Heuchera X cuneata Howell (pro. sp.) -- accepted -- alumroot
  Hieracium longiberbe Howell -- accepted -- longbeard hawkweed
  Horkelia caruifolia Rydb. ex Howell -- not accepted
  Horkelia daucifolia var. caruifolia (Rydb. ex Howell) Ertter & Reveal -- accepted -- carrotleaf horkelia
  Horkelia fusca ssp. pseudocapitata (Rydb. ex Howell) D.D. Keck -- not accepted -- littlehead horkelia
  Horkelia fusca var. pseudocapitata (Rydb. ex Howell) M. Peck -- accepted
  Horkelia gordonii var. alpicola (Rydb. ex Howell) Rydb. -- not accepted
  Horkelia hendersonii Howell -- accepted -- Henderson's horkelia
  Horkelia pseudocapitata Rydb. ex Howell -- not accepted
  Horkelia tularensis (J.T. Howell) Munz -- accepted -- Kern Plateau horkelia, Tulare horkelia
  Hypopitys fimbriata (A. Gray) Howell -- not accepted
  Iris chrysophylla Howell -- accepted -- yellowleaf iris
  Iris tenax ssp. chrysophylla (Howell) Q.D. Clarkson -- not accepted
  Ivesia aperta (J.T. Howell) Munz -- accepted -- Sierra Valley ivesia, Sierra Valley mousetail
  Ivesia aperta var. aperta (J.T. Howell) Munz -- accepted -- Sierra Valley ivesia, Sierra Valley mousetail
  Ivesia arizonica (Eastw. ex J.T. Howell) Ertter -- accepted -- rock whitefeather, rock-whitefeather
  Ivesia arizonica var. arizonica (Eastw. ex J.T. Howell) Ertter -- accepted -- Arizona whitefeather
  Ivesia gordonii var. alpicola (Rydb. ex Howell) Ertter & Reveal -- accepted -- Gordon's ivesia
  Ivesia patellifera (J.T. Howell) Ertter -- accepted -- Kingston Mountain mousetail, Kingston Mountains cinquefoil
  Juncus bufonius var. cogdonii (S. Watson) J.T. Howell -- not accepted
  Juncus bufonius var. congdonii (S. Watson) J.T. Howell -- not accepted
  Lasthenia californica ssp. bakeri (J.T. Howell) R. Chan -- accepted -- Baker's goldfields
  Lasthenia macrantha ssp. bakeri (J.T. Howell) Ornduff -- not accepted -- Baker's goldfields
  Lathyrus lanceolatus Howell -- not accepted
  Lathyrus nevadensis ssp. lanceolatus (Howell) C.L. Hitchc. -- not accepted -- Sierra pea
  Lathyrus nevadensis ssp. lanceolatus var. lanceolatus (Howell) C.L. Hitchc. -- not accepted
  Lepidium acutidens (A. Gray) Howell -- accepted -- alkali pepperwort
  Lepidium nitidum var. oreganum (Howell ex Greene) C.L. Hitchc. -- not accepted -- shining pepperweed
  Lessingia germanorum var. glandulifera (A. Gray) J.T. Howell -- not accepted
  Lessingia germanorum var. lemmonii (A. Gray) J.T. Howell -- not accepted
  Lessingia germanorum var. parvula (Greene) J.T. Howell -- not accepted
  Lessingia germanorum var. pectinata (Greene) J.T. Howell -- not accepted
  Lessingia germanorum var. peirsonii J.T. Howell -- not accepted
  Lessingia germanorum var. ramulosissima (A. Nelson) J.T. Howell -- not accepted
  Lessingia germanorum var. tenuis (A. Gray) J.T. Howell -- not accepted
  Lessingia germanorum var. tomentosa (Greene) J.T. Howell -- not accepted
  Lessingia glandulifera var. peirsonii (J.T. Howell) Markos -- accepted -- Peirson's lessingia
  Lessingia hololeuca var. arachnoidea (Greene) J.T. Howell -- not accepted
  Lessingia lemmonii var. peirsonii (J.T. Howell) Ferris -- not accepted -- Peirson's lessingia
  Lessingia nemaclada var. albiflora (Eastw.) J.T. Howell -- not accepted -- slenderstem lessingia
  Lessingia nemaclada var. mendocina (Greene) J.T. Howell -- not accepted -- Mendocino lessingia
  Lessingia pectinata var. tenuipes (J.T. Howell) Markos -- accepted
  Lessingia ramulosa var. micradenia (Greene) J.T. Howell -- not accepted
  Lessingia virgata var. glomerata (Greene) J.T. Howell -- not accepted -- wand lessingia
  Lewisia cantelovii J.T. Howell -- accepted -- Cantelow's lewisia
  Lewisia cantelowii J.T. Howell -- not accepted -- Cantelon's lewisia
  Lewisia columbiana (Howell ex A. Gray) B.L. Rob. -- accepted -- Columbian lewisia
  Lewisia columbiana var. columbiana (Howell ex A. Gray) B.L. Rob. -- accepted -- Columbian lewisia
  Limnanthes alba ssp. gracilis (Howell) Morin -- accepted -- slender meadowfoam
  Limnanthes bakeri J.T. Howell -- accepted -- Baker's meadowfoam
  Limnanthes floccosa Howell -- accepted -- woolly meadowfoam
  Limnanthes floccosa ssp. floccosa Howell -- accepted -- woolly meadowfoam
  Limnanthes floccosa ssp. pumila (Howell) Arroyo -- accepted -- dwarf meadowfoam, woolly meadowfoam
  Limnanthes floccosa var. pumila (Howell) C.T. Mason -- not accepted
  Limnanthes gracilis Howell -- not accepted -- slender meadowfoam
  Limnanthes gracilis ssp. gracilis Howell -- not accepted -- slender meadowfoam
  Limnanthes pumila Howell -- not accepted
  Linanthus pygmaeus (Brand) J.T. Howell -- not accepted -- pygmy linanthus
  Linanthus pygmaeus ssp. pygmaeus (Brand) J.T. Howell -- not accepted -- pygmy linanthus
  Lithophragma campanulatum Howell -- accepted -- Siskiyou Mountain woodland-star
  Lithophragma heterophyllum var. campanulatum (Howell) M. Peck -- not accepted
  Lomatium gormanii (Howell) J.M. Coult. & Rose -- accepted -- Gorman's biscuitroot
  Lomatium minus (Rose ex Howell) Mathias & Constance -- accepted -- Day Valley desert-parsley, Day Valley desertparsley
  Lupinus arbustus ssp. arbustus var. montanus (Howell) D.B. Dunn -- not accepted -- longspur lupine
  Lupinus arbustus var. montanus (Howell) D.B. Dunn -- accepted -- longspur lupine
  Lupinus canescens Howell -- not accepted
  Lupinus douglasii var. fallax (Greene) J.T. Howell -- not accepted
  Lupinus leucophyllus ssp. leucophyllus var. canescens (Howell) C.P. Sm. -- not accepted -- velvet lupine
  Lupinus leucophyllus var. canescens (Howell) C.P. Sm. -- accepted -- velvet lupine
  Lupinus mucronulatus Howell -- not accepted
  Lupinus polyphyllus var. saxosus (Howell) Barneby -- not accepted
  Lupinus saxosus Howell -- accepted -- rock lupine, stone lupine
  Lupinus saxosus var. saxosus Howell -- accepted -- rock lupine, stonyground lupine
  Machaeranthera attenuata Howell -- not accepted
  Machaeranthera eradiata (A. Gray) Howell -- not accepted
  Marah oregana (Torr. ex A. Gray) Howell -- accepted -- coastal manroot, western wildcucumber
  Marah oreganus (Torr. ex A. Gray) Howell -- not accepted -- coastal manroot, western wildcucumber
  Melica argentea (Howell ex Vasey) Beal -- not accepted
  Melica geyeri var. aristulata J.T. Howell -- accepted -- Geyer's oniongrass
  Micranthes oregana (Howell) Small -- accepted -- bog saxifrage, Oregon saxifrage
  Microseris paludosa (Greene) J.T. Howell -- accepted -- marsh silverpuffs
  Mimulus cleistogamus J.T. Howell -- accepted -- selfing monkeyflower
  Mimulus grandiflorus Howell -- not accepted
  Mimulus hirsutus Howell -- not accepted
  Mitellastra caulescens (Nutt.) Howell -- not accepted
  Monardella purpurea Howell -- accepted -- serpentine monardella
  Monardella sheltonii (Torr.) Howell -- accepted -- Shelton's monardella
  Montia arenicola (L.F. Hend.) Howell -- not accepted
  Montia dichotoma (Nutt.) Howell -- accepted -- dwarf minerslettuce
  Montia gypsophiloides (Fisch. & C.A. Mey.) Howell -- not accepted
  Montia parviflora (Douglas ex Hook.) Howell -- not accepted
  Montia perfoliata (Donn ex Willd.) Howell -- not accepted -- miner's lettuce
  Montia sibirica (L.) Howell -- not accepted
  Montia spathulata (Douglas) Howell -- not accepted
  Montia spathulata var. rosulata (Eastw.) J.T. Howell -- not accepted
  Montia spathulata var. spathulata (Douglas) Howell -- not accepted
  Myosurus lepturus (A. Gray) Howell -- not accepted
  Nama retrorsa J.T. Howell -- accepted -- betatakin fiddleleaf
  Nama retrorsum J.T. Howell -- not accepted -- betatakin fiddleleaf
  Navarretia nigelliformis ssp. radians (J.T. Howell) A.G. Day -- accepted -- adobe navarretia
  Navarretia nigelliformis var. radians J.T. Howell -- not accepted
  Nemacladus twisselmannii J.T. Howell -- accepted -- Twisselmann's nemacladus, Twisselmann's threadplant
  Opuntia echios J.T. Howell -- not accepted
  Opuntia megasperma J.T. Howell -- not accepted
  Opuntia saxicola J.T. Howell -- not accepted
  Oreobroma nevadense (A. Gray) Howell -- not accepted
  Oreobroma pygmaeum (A. Gray) Howell -- not accepted
  Orthocarpus densiflorus var. noctuinus (Eastw.) J.T. Howell -- not accepted
  Orthocarpus faucibarbatus var. albidus (D.D. Keck) J.T. Howell -- not accepted
  Oxycoccus palustris var. intermedius (A. Gray) Howell -- not accepted
  Packera eurycephala var. lewisrosei (J.T. Howell) J.F. Bain -- accepted -- Lewis' groundsel
  Penstemon cardwellii Howell -- accepted -- Cardwell's beardtongue
  Penstemon papillatus J.T. Howell -- accepted -- Inyo beardtongue, Inyo penstemon
  Penstemon rupicola (Piper) Howell -- accepted -- cliff beardtongue
  Penstemon whitedii ssp. dayanus (Howell) D.D. Keck -- not accepted
  Pentagramma triangularis ssp. semipallida (J.T. Howell) Yatsk., Windham & E. Wollenw. -- accepted -- goldback fern
  Phacelia adenophora J.T. Howell -- accepted -- glandbearing phacelia, glandular yellow phacelia
  Phacelia affinis var. patens J.T. Howell -- not accepted
  Phacelia austromontana J.T. Howell -- accepted -- southern mountain phacelia, Southern Sierra phacelia
  Phacelia barnebyana J.T. Howell -- accepted -- Barneby's phacelia
  Phacelia cicutaria var. heliophila (J.F. Macbr.) J.T. Howell -- not accepted
  Phacelia cicutaria var. hispida (A. Gray) J.T. Howell -- accepted -- caterpillar phacelia
  Phacelia cicutaria var. hubbyi (J.F. Macbr.) J.T. Howell -- accepted -- caterpillar phacelia
  Phacelia ciliata var. opaca J.T. Howell -- accepted -- Great Valley phacelia, Merced phacelia
  Phacelia dalesiana J.T. Howell -- accepted -- Scott Mountain phacelia, Trinity phacelia
  Phacelia demissa var. heterotricha J.T. Howell -- not accepted
  Phacelia demissa var. typica J.T. Howell -- not accepted
  Phacelia divaricata var. continentis (J.T. Howell) Munz -- not accepted
  Phacelia egena (Greene ex Brand) Greene ex J.T. Howell -- accepted -- Kaweah River phacelia, Kaweah river scorpion-weed
  Phacelia eisenii var. brandegeeana J.T. Howell -- not accepted
  Phacelia glaberrima (Torr. ex S. Watson) J.T. Howell -- accepted -- Reese River phacelia, southwestern phacelia
  Phacelia greenei J.T. Howell -- accepted -- Scott Valley phacelia
  Phacelia humilis var. dudleyi J.T. Howell -- accepted -- Dudley's phacelia
  Phacelia indecora J.T. Howell -- accepted -- drab phacelia
  Phacelia insularis var. continentis J.T. Howell -- accepted -- North Coast phacelia, northcoast phacelia
  Phacelia inundata J.T. Howell -- accepted -- playa phacelia, playa yellow phacelia
  Phacelia inyoensis (J.F. Macbr.) J.T. Howell -- accepted -- Inyo phacelia
  Phacelia ivesiana var. pediculoides J.T. Howell -- accepted -- Ives' phacelia, louse phacelia, lousewort scorpion-weed
  Phacelia ivesiana var. typica J.T. Howell -- not accepted
  Phacelia laxiflora J.T. Howell -- accepted -- dozing phacelia, dozing scorpion-weed, nodding phacelia
  Phacelia leonis J.T. Howell -- accepted -- Siskiyou phacelia
  Phacelia lutea (Hook. & Arn.) J.T. Howell -- accepted -- yellow phacelia
  Phacelia lutea var. lutea (Hook. & Arn.) J.T. Howell -- accepted -- yellow phacelia
  Phacelia lutea var. purpurascens J.T. Howell -- not accepted
  Phacelia lutea var. submutica (J.T. Howell) Cronquist -- not accepted
  Phacelia nevadensis J.T. Howell -- not accepted
  Phacelia peckii J.T. Howell -- accepted -- Peck's phacelia
  Phacelia pediculoides (J.T. Howell) Constance -- not accepted
  Phacelia peirsoniana J.T. Howell -- accepted -- handsome phacelia, trail phacelia
  Phacelia perityloides var. laxiflora (J.T. Howell) Cronquist -- not accepted
  Phacelia pulchella var. gooddingii (Brand) J.T. Howell -- accepted -- Goodding's phacelia
  Phacelia pulchella var. sabulonum J.T. Howell -- accepted -- beautiful phacelia
  Phacelia pulchella var. typica J.T. Howell -- not accepted
  Phacelia quickii J.T. Howell -- accepted -- Quick's phacelia
  Phacelia salima (A. Nelson) J.T. Howell -- not accepted
  Phacelia salina (A. Nelson) J.T. Howell -- accepted -- alkaline phacelia, Bitter Creek phacelia
  Phacelia scopulina (A. Nelson) J.T. Howell -- accepted -- Debeque phacelia, Debeque scorpion-weed, prostrate phacelia
  Phacelia scopulina var. scopulina (A. Nelson) J.T. Howell -- accepted -- Debeque phacelia
  Phacelia scopulina var. submutica (J.T. Howell) Halse -- accepted -- Debeque phacelia
  Phacelia suaveolens var. keckii (Munz & I.M. Johnst.) J.T. Howell -- not accepted
  Phacelia submutica J.T. Howell -- not accepted -- DeBeque phacelia
  Phacelia tetramera J.T. Howell -- accepted -- fourpart phacelia
  Phacelia verna Howell -- accepted -- spring phacelia
  Phoradendron libocedri (Engelm.) Howell -- not accepted -- incense cedar mistletoe
  Physocarpus alternans (M.E. Jones) J.T. Howell -- accepted -- dwarf ninebark
  Physocarpus alternans ssp. alternans (M.E. Jones) J.T. Howell -- not accepted -- dwarf ninebark
  Physocarpus alternans ssp. annulatus J.T. Howell -- not accepted -- dwarf ninebark
  Physocarpus alternans ssp. panamintensis J.T. Howell -- not accepted -- dwarf ninebark
  Pityrogramma semipallida J.T. Howell -- not accepted
  Pityrogramma triangularis var. semipallida J.T. Howell -- not accepted
  Plagiobothrys bracteatus (Howell) I.M. Johnst. -- accepted -- bracted popcornflower
  Plagiobothrys bracteatus var. bracteatus (Howell) I.M. Johnst. -- accepted -- bracted popcornflower
  Plagiobothrys uncinatus J.T. Howell -- accepted -- Salinas Valley popcornflower
  Pleuricospora longipetala Howell -- not accepted
  Pleuropogon hooveranus (L. Bensen) J. T. Howell -- not accepted
  Pleuropogon hooverianus (L.D. Benson) J.T. Howell -- accepted -- North Coast semaphoregrass
  Poa argentea Howell ex Vasey -- not accepted
  Poa canbyi (Scribn.) Howell -- not accepted
  Poa candyi (Scribn.) T. Howell -- not accepted
  Poa sierrae J.T. Howell -- accepted -- Sierra bluegrass
  Pogogyne abramsii J.T. Howell -- accepted -- San Diego mesamint, San Diego pogogyne
  Pogogyne clareana J.T. Howell -- accepted -- Santa Lucia mint, Santa Lucia pogogyne
  Pogogyne douglasii ssp. minor J.T. Howell -- not accepted -- Douglas' mesamint
  Pogogyne douglasii ssp. parviflora (Benth.) J.T. Howell -- not accepted -- Douglas' mesamint
  Potentilla anserina ssp. pacifica (Howell) Rousi -- accepted -- Pacific silverweed
  Potentilla aperta J.T. Howell -- not accepted
  Potentilla baileyi var. setosa (S. Watson) J.T. Howell -- not accepted
  Potentilla caruifolia (Rydb. ex Howell) Crum -- not accepted
  Potentilla ciliata Howell -- not accepted
  Potentilla congesta var. nemorosa (D.D. Keck) J.T. Howell -- not accepted
  Potentilla douglasii var. parviflora (Nutt. ex Hook. & Arn.) J.T. Howell -- not accepted -- pinewoods horkelia
  Potentilla douglasii var. pseudocapitata (Rydb. ex Howell) Jeps. -- not accepted -- pinewoods horkelia
  Potentilla egedii ssp. pacifica (Howell) L.A. Sergienko -- not accepted
  Potentilla egedii var. grandis (Torr. & A. Gray) J.T. Howell -- not accepted
  Potentilla hendersonii (J.T. Howell) J.T. Howell -- not accepted
  Potentilla lindleyi var. puberula (Rydb.) J.T. Howell -- not accepted
  Potentilla lindleyi var. sericea (A. Gray) J.T. Howell -- not accepted
  Potentilla lycopodioides (A. Gray) Baill. ex J.T. Howell -- not accepted
  Potentilla lycopodioides var. megalopetala (Rydb.) J.T. Howell -- not accepted
  Potentilla lycopodioides var. scandularis (Rydb.) J.T. Howell -- not accepted
  Potentilla marinensis (Elmer) J.T. Howell -- not accepted
  Potentilla osterhoutii (A. Nelson) J.T. Howell -- not accepted
  Potentilla osterhoutii var. saxosa (Brandegee) J.T. Howell -- not accepted
  Potentilla pacifica Howell -- not accepted
  Potentilla patellifera J.T. Howell -- not accepted
  Potentilla sericoleuca (Rydb.) J.T. Howell -- not accepted
  Potentilla tilingii var. flavescens (Rydb.) J.T. Howell -- not accepted
  Potentilla tularensis J.T. Howell -- not accepted
  Potentilla tweedyi (Rydb.) J.T. Howell -- not accepted
  Psilochenia runcinata ssp. hispidulosa (Howell ex Rydb.) W.A. Weber -- not accepted
  Purpusia arizonica Eastw. ex J.T. Howell -- not accepted
  Pyrola aphylla var. paucifolia Howell -- not accepted
  Quercus agrifolia var. oxyadenia (Torr.) J.T. Howell -- not accepted -- coastal live oak
  Rhamnus californica ssp. occidentalis (Howell) C.B. Wolf -- accepted -- California buckthorn
  Rhamnus californica var. occidentalis (Howell) Jeps. -- not accepted
  Ribes acerifolium Howell -- accepted -- mapleleaf currant
  Rorippa columbiae (S. Watson) Howell -- accepted -- Columbia watercress, Columbian yellowcress
  Rubus spectabilis var. franciscanus (Rydb.) J.T. Howell -- not accepted -- salmonberry
  Rubus ursinus ssp. ursinus var. sirbenus (L.H. Bailey) J.T. Howell -- not accepted -- California blackberry
  Rubus ursinus var. eastwoodianus (Rydb.) J.T. Howell -- not accepted
  Rubus ursinus var. sirbenus (L.H. Bailey) J.T. Howell -- not accepted -- California blackberry
  Rumex occidentalis var. procerus (Greene) J.T. Howell -- not accepted
  Rumex salicifolius var. crassus (Rech. f.) J.T. Howell -- not accepted -- willow dock
  Sagittaria esculenta Howell -- not accepted
  Salix congesta (Bebb ex Rothr.) J.T. Howell -- not accepted
  Salix fluviatilis var. tenerrima (L.F. Hend.) Howell -- not accepted
  Saxifraga oregana Howell -- not accepted -- box saxifrage, Oregon saxifrage
  Sedum ciliosum Howell -- not accepted
  Sedum douglasii ssp. ciliosum (Howell) R.T. Clausen -- not accepted
  Sedum radiatum ssp. ciliosum (Howell) R.T. Clausen -- not accepted -- Coast Range stonecrop
  Sedum radiatum var. ciliosum (Howell) H. Ohba -- accepted -- Coast Range stonecrop
  Sedum stenopetalum ssp. ciliosum (Howell) R.T. Clausen -- not accepted
  Senecio adamsii Howell -- not accepted
  Senecio eurycephalus var. lewisrosei (J.T. Howell) T.M. Barkley -- not accepted -- Lewis' groundsel
  Senecio foetidus J.T. Howell -- not accepted
  Senecio lewisrosei J.T. Howell -- not accepted
  Sidalcea malviflora ssp. virgata (Howell) C.L. Hitchc. -- not accepted -- dwarf checkerbloom
  Sidalcea malviflora var. virgata (Howell) Dimling -- not accepted
  Sidalcea stipularis J.T. Howell & G.H. True -- accepted -- Scadden Flat checkerbloom, Scadden Flat checkermallow
  Sidalcea virgata Howell -- accepted -- virgate checkerbloom
  Sophia pinnata (Walter) Howell -- not accepted
  Stanleya confertiflora (B.L. Rob.) Howell -- accepted -- Oregon princesplume
  Steironema laevigatum Howell -- not accepted -- fringed loosestrife
  Stellaria borealis var. simcoei (Howell) Fernald -- not accepted
  Stellaria calycantha var. simcoei (Howell) Fernald -- not accepted
  Stellaria simcoei (Howell) C.L. Hitchc. -- not accepted
  Stenogonum flexum (M.E. Jones) Reveal & J.T. Howell -- accepted -- bent two-whorl buckwheat, bent twowhorl buckwheat
  Streptanthella longirostris var. derelicta J.T. Howell -- not accepted
  Streptanthus amplexicaulis var. barbarae J.T. Howell -- not accepted
  Streptanthus cordatus var. piutensis J.T. Howell -- accepted -- heartleaf twistflower, Piute Mountains jewelflower
  Streptanthus farnsworthianus J.T. Howell -- accepted -- Evalyn's jewelflower, Farnsworth's jewelflower
  Streptanthus fenestratus (Greene) J.T. Howell -- accepted -- Tehipite Valley jewelflower
  Stylocline amphibola (A. Gray) J.T. Howell -- not accepted
  Stylocline amphiloba (A. Gray) J.T. Howell -- not accepted
  Tellima odorata Howell -- not accepted
  Thermopsis gracilis Howell -- accepted -- slender goldenbanner
  Thermopsis gracilis var. gracilis Howell -- not accepted -- slender goldenbanner
  Thermopsis macrophylla var. agnina J.T. Howell -- not accepted -- Santa Barbara false-lupine
  Thermopsis robusta Howell -- accepted -- showy goldenbanner
  Trifolium eriocephalum var. harneyense (Howell) McDermott -- not accepted
  Trifolium longipes ssp. oreganum (Howell) J.M. Gillett -- accepted -- Oregon clover
  Trifolium longipes var. oreganum (Howell) Isely -- not accepted
  Trifolium oreganum Howell -- not accepted
  Trifolium rusbyi ssp. oreganum (Howell) D. Heller & Zohary -- not accepted
  Triglochin concinna var. debilis (M.E. Jones) J.T. Howell -- not accepted
  Triglochin concinnum var. debile (M.E. Jones) J.T. Howell -- not accepted
  Trillium chloropetalum (Torr.) Howell -- accepted -- giant wakerobin
  Trillium chloropetalum var. chloropetalum (Torr.) Howell -- accepted -- giant wakerobin
  Trisetum spicatum var. projectum (Louis-Marie) J.T. Howell -- not accepted
  Vaccinium alaskaense Howell -- not accepted
  Vaccinium alaskense Howell -- not accepted
  Viola occidentalis (A. Gray) Howell -- not accepted
  Viola purpurea var. integrifolia (M.S. Baker & J.C. Clausen) J.T. Howell -- accepted -- goosefoot violet
  Viola purpurea var. mohavensis (M.S. Baker & J.C. Clausen) J.T. Howell -- accepted -- goosefoot violet
  Viola trinervata (Howell) Howell ex A. Gray -- accepted -- Rainier violet
 
 Kingdom Bacteria
  Actinomyces viscosus (Howell et al., 1965) Georg et al., 1969 -- valid
 
 Kingdom Chromista
  Alexandrium monilatum (Howell) F. J. R. Taylor, 1979 -- accepted
   

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