California

• Alameda 06001
  1,856 taxa Open ↗
• Alpine 06003
  1,174 taxa Open ↗
• Amador 06005
  1,226 taxa Open ↗
• Butte 06007
  2,704 taxa Open ↗
• Calaveras 06009
  1,227 taxa Open ↗
• Colusa 06011
  1,330 taxa Open ↗
• Contra Costa 06013
  1,712 taxa Open ↗
• Del Norte 06015
  1,424 taxa Open ↗
• El Dorado 06017
  1,950 taxa Open ↗
• Fresno 06019
  2,373 taxa Open ↗

Showing 6,901–6,950 of 9,954.

• 
  Onopordum illyricum L. Introduced ONIL

  Illyrian cottonthistle · Asteraceae 1 county
• 
  Onopordum tauricum Willd. Introduced ONTA

  bull cottonthistle · Asteraceae 5 counties
• 
  Ophioglossum californicum Prantl Native OPCA8

  California adderstongue · Ophioglossaceae 10 counties
• 
  Ophioglossum pusillum Raf. Native OPPU3

  northern adderstongue · Ophioglossaceae 3 counties
• 
  Opuntia basilaris Engelm. & J.M. Bigelow Native OPBA2

  beavertail pricklypear · Cactaceae 8 counties
• 
  Opuntia basilaris Engelm. & J.M. Bigelow var. basilaris Native OPBAB2

  beavertail pricklypear · Cactaceae 7 counties
• 
  Opuntia basilaris Engelm. & J.M. Bigelow var. brachyclada (Griffiths) Munz Native OPBAB

  beavertail pricklypear · Cactaceae 2 counties
• 
  Opuntia basilaris Engelm. & J.M. Bigelow var. treleasei (J.M. Coult.) J.M. Coult. ex Toumey Native OPBAT

  Trelease's beavertail pricklypear · Cactaceae 1 county
• 
  Opuntia chlorotica Engelm. & J.M. Bigelow Native OPCH

  dollarjoint pricklypear · Cactaceae 4 counties
• 
  Opuntia engelmannii Salm-Dyck ex Engelm. Native OPEN3

  cactus apple · Cactaceae 1 county
• 
  Opuntia engelmannii Salm-Dyck ex Engelm. var. engelmannii Native OPENE

  cactus apple · Cactaceae 1 county
• 
  Opuntia ficus-indica (L.) Mill. Introduced OPFI

  Barbary fig · Cactaceae 8 counties
• 
  Opuntia fragilis (Nutt.) Haw. Native OPFR

  brittle pricklypear · Cactaceae 1 county
• 
  Opuntia littoralis (Engelm.) Cockerell Native OPLI3

  coastal pricklypear · Cactaceae 8 counties
• 
  Opuntia littoralis (Engelm.) Cockerell var. littoralis Native OPLIL3

  coastal pricklypear · Cactaceae 1 county
• 
  Opuntia oricola Philbrick Native OPOR

  chaparral pricklypear · Cactaceae 5 counties
• 
  Opuntia phaeacantha Engelm. Native OPPH

  tulip pricklypear · Cactaceae 7 counties
• 
  Opuntia polyacantha Haw. Native OPPO

  plains pricklypear · Cactaceae 7 counties
• 
  Opuntia polyacantha Haw. var. erinacea (Engelm. & J.M. Bigelow ex Engelm.) Parfitt Native OPPOE

  grizzlybear pricklypear · Cactaceae 7 counties
• 
  Opuntia polyacantha Haw. var. polyacantha Native OPPOP

  hairspine pricklypear · Cactaceae 5 counties
• ⚘
  Opuntia ×curvospina Griffiths (pro sp.) [chlorotica × phaeacantha] Native OPCU2

  searchlight pricklypear · Cactaceae 1 county
• ⚘
  Opuntia ×demissa Griffiths (pro sp.) [ficus-indica × sp.] Native OPDE

  pricklypear · Cactaceae 1 county
• ⚘
  Opuntia ×occidentalis Engelm. & J.M. Bigelow (pro sp.) [littoralis × (engelmannii × phaeacantha)] Native OPOC2

  pricklypear · Cactaceae 4 counties
• ⚘
  Opuntia ×vaseyi (J.M. Coult.) Britton & Rose [littoralis × phaeacantha] Native OPVA4

  Vasey's coastal pricklypear · Cactaceae 5 counties
• 
  Orcuttia californica Vasey Native ORCA

  California Orcutt grass · Poaceae 4 counties
• 
  Orcuttia inaequalis Hoover Native ORIN

  San Joaquin Valley Orcutt grass · Poaceae 5 counties
• 
  Orcuttia pilosa Hoover Native ORPI

  hairy Orcutt grass · Poaceae 6 counties
• 
  Orcuttia tenuis Hitchc. Native ORTE

  slender Orcutt grass · Poaceae 9 counties
• 
  Orcuttia viscida (Hoover) J. Reeder Native ORVI2

  Sacramento Orcutt grass · Poaceae 1 county
• 
  Oreonana clementis (M.E. Jones) Jeps. Native ORCL

  pygmy mountainparsley · Apiaceae 4 counties
• 
  Oreonana purpurascens Shevock & Constance Native ORPU5

  purple mountainparsley · Apiaceae 1 county
• 
  Oreonana vestita (S. Watson) Jeps. Native ORVE

  woolly mountainparsley · Apiaceae 3 counties
• 
  Oreostemma alpigenum (Torr. & A. Gray) Greene Native ORAL4

  tundra aster · Asteraceae 24 counties
• 
  Oreostemma alpigenum (Torr. & A. Gray) Greene var. andersonii (A. Gray) G.L. Nesom Native ORALA3

  tundra aster · Asteraceae 23 counties
• 
  Oreostemma alpigenum (Torr. & A. Gray) Greene var. haydenii (Porter) G.L. Nesom Native ORALH

  tundra aster · Asteraceae 1 county
• 
  Oreostemma elatum (Greene) Greene Native OREL4

  Plumas alpine aster · Asteraceae 3 counties
• 
  Oreostemma peirsonii (Sharsm.) G.L. Nesom Native ORPE4

  Peirson's aster · Asteraceae 3 counties
• 
  Origanum vulgare L. Introduced ORVU

  oregano · Lamiaceae 1 county
• 
  Ornithogalum umbellatum L. Introduced ORUM

  star of Bethlehem · Liliaceae 2 counties
• 
  Ornithopus pinnatus (Mill.) Druce Introduced ORPI3

  yellow bird's-foot · Fabaceae 1 county
• 
  Ornithopus sativus Brot. Introduced ORSA2

  common bird's-foot · Fabaceae 1 county
• 
  Ornithopus sativus Brot. ssp. isthmocarpus (Coss.) Dostál Introduced ORSAI

  common bird's-foot · Fabaceae 1 county
• 
  Ornithostaphylos oppositifolia (Parry) Small Native OROP

  Baja birdbush · Ericaceae 1 county
• 
  Orobanche aegyptiaca Pers. Introduced ORAE3

  Egyptian broomrape · Orobanchaceae 1 county
• 
  Orobanche bulbosa (A. Gray) G. Beck Native ORBU

  chaparral broomrape · Orobanchaceae 26 counties
• 
  Orobanche californica Cham. & Schltdl. Native ORCA2

  California broomrape · Orobanchaceae 32 counties
• 
  Orobanche californica Cham. & Schltdl. ssp. californica Native ORCAC2

  California broomrape · Orobanchaceae 14 counties
• 
  Orobanche californica Cham. & Schltdl. ssp. condensa Heckard Native ORCAC

  California broomrape · Orobanchaceae 1 county
• 
  Orobanche californica Cham. & Schltdl. ssp. feudgei (Munz) Heckard Native ORCAF

  California broomrape · Orobanchaceae 8 counties
• 
  Orobanche californica Cham. & Schltdl. ssp. grandis Heckard Native ORCAG

  California broomrape · Orobanchaceae 4 counties