| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| CINNA | Cinna L. | woodreed | Poaceae
|
| CIAR8 | Cinnamomum aromaticum Nees | cassia | Lauraceae
|
| CIBU2 | Cinnamomum burmannii (Nees & Th. Nees) Nees ex Blume | Padang cassia | Lauraceae
|
| CICA | Cinnamomum camphora (L.) J. Presl | camphortree | Lauraceae
|
| CICA18 | Cinnamomum cassia Nees ex Blume | Cinnamomum aromaticum | Lauraceae
|
| CIEL2 | Cinnamomum elongatum (Vahl ex Nees) Kosterm. | laurel avispillo | Lauraceae
|
| CIMO3 | Cinnamomum montanum (Sw.) Bercht. & J. Presl | avispillo | Lauraceae
|
| CISE2 | Cinnamomum sessilifolium Kanehira | cinnamon | Lauraceae
|
| CITA2 | Cinnamomum tamala (Buch.-Ham.) T. Nees & Eberm. | indian bark | Lauraceae
|
| CIVE2 | Cinnamomum verum J. Presl | cinnamon | Lauraceae
|
| CIZE2 | Cinnamomum zeylanicum Blume | Cinnamomum verum | Lauraceae
|
| CINNA2 | Cinnamomum Schaeffer | cinnamon | Lauraceae
|
| CIMA6 | Cipura martinicensis (Jacq.) Kunth | Trimezia martinicensis | Iridaceae
|
| CIALA | Circaea alpina L. ssp. alpina | small enchanter's nightshade | Onagraceae
|
| CIALP2 | Circaea alpina L. ssp. pacifica (Aschers. & Magnus) Raven | small enchanter's nightshade | Onagraceae
|
| CIALP3 | Circaea alpina L. var. pacifica (Aschers. & Magnus) M.E. Jones | Circaea alpina ssp. pacifica | Onagraceae
|
| CIAL | Circaea alpina L. | small enchanter's nightshade | Onagraceae
|
| CICAV | Circaea canadensis (L.) Hill var. virginiana Fern. | Circaea lutetiana ssp. canadensis | Onagraceae
|
| CICA13 | Circaea canadensis sensu Fern. | Circaea intermedia | Onagraceae
|
| CIIN4 | Circaea �intermedia Ehrh. (pro sp.) | | Onagraceae
|
| CILA9 | Circaea latifolia Hill | Circaea lutetiana ssp. canadensis | Onagraceae
|
| CILUC | Circaea lutetiana L. ssp. canadensis (L.) Aschers. & Magnus | broadleaf enchanter's nightshade | Onagraceae
|
| CILUC2 | Circaea lutetiana L. var. canadensis L. | Circaea lutetiana ssp. canadensis | Onagraceae
|
| CILU | Circaea lutetiana L. | broadleaf enchanter's nightshade | Onagraceae
|
| CIPA10 | Circaea pacifica Aschers. & Magnus | Circaea alpina ssp. pacifica | Onagraceae
|
| CIQUC3 | Circaea quadrisulcata (Maxim.) Franch. & Savigny ssp. canadensis (L.) A.& D. L�ve | Circaea lutetiana ssp. canadensis | Onagraceae
|
| CIQUC2 | Circaea quadrisulcata (Maxim.) Franch. & Savigny var. canadensis (L.) Hara | Circaea lutetiana ssp. canadensis | Onagraceae
|
| CIRCA | Circaea L. | enchanter's nightshade | Onagraceae
|
| CIBO4 | Cirriphyllum boscii (Schwaegr.) Grout | Bryoandersonia illecebra | Brachytheciaceae
|
| CIBR5 | Cirriphyllum brandegeei (Aust.) Grout | Brandegee's cirriphyllum moss | Brachytheciaceae
|
| CICIC | Cirriphyllum cirrosum (Schwaegr. in Schultes) Grout var. coloradense (Aust.) Grout | Cirriphyllum cirrosum | Brachytheciaceae
|
| CICI70 | Cirriphyllum cirrosum (Schwaegr. in Schultes) Grout | cirriphyllum moss | Brachytheciaceae
|
| CIIL | Cirriphyllum illecebrum (Hedw.) L. Koch | Bryoandersonia illecebra | Brachytheciaceae
|
| CIPI70 | Cirriphyllum piliferum (Hedw.) Grout | cirriphyllum moss | Brachytheciaceae
|
| CIRRI2 | Cirriphyllum Grout | cirriphyllum moss | Brachytheciaceae
|
| CIAC | Cirsium acanthodontum Blake | Cirsium remotifolium ssp. remotifolium | Asteraceae
|
| CIACA | Cirsium acaule All. var. americanum Gray | Cirsium tioganum var. tioganum | Asteraceae
|
| CIAC3 | Cirsium acaulescens (Rydb.) K. Schum. | Cirsium tioganum var. tioganum | Asteraceae
|
| CIAC4 | Cirsium acuatum (Osterhout) Petrak | Cirsium undulatum var. tracyi | Asteraceae
|
| CIALB | Cirsium altissimum (L.) Hill var. biltmoreanum Petrak | Cirsium altissimum | Asteraceae
|
| CIALF | Cirsium altissimum (L.) Hill var. filipendulum (Engelm.) Gray | Cirsium engelmannii | Asteraceae
|
| CIAL2 | Cirsium altissimum (L.) Hill | tall thistle | Asteraceae
|
| CIAM2 | Cirsium amblylepis Petrak | Mt. Tamalpais thistle | Asteraceae
|
| CIAM4 | Cirsium americanum (Gray) K. Schum. | Cirsium tioganum var. tioganum | Asteraceae
|
| CIAN | Cirsium andersonii (Gray) Petrak | rose thistle | Asteraceae
|
| CIAN2 | Cirsium andrewsii (Gray) Jepson | Franciscan thistle | Asteraceae
|
| CIAR6 | Cirsium araneans Rydb. | jeweled thistle | Asteraceae
|
| CIAR7 | Cirsium arcuum A. Nels. | powderpuff thistle | Asteraceae
|
| CIAR9 | Cirsium aridum Dorn | desert thistle | Asteraceae
|
| CIARA | Cirsium arizonicum (Gray) Petrak var. arizonicum | Arizona thistle | Asteraceae
|
| CIARN | Cirsium arizonicum (Gray) Petrak var. nidulum (M.E. Jones) Welsh | Arizona thistle | Asteraceae
|
| CIAR3 | Cirsium arizonicum (Gray) Petrak | Arizona thistle | Asteraceae
|
| CIARA3 | Cirsium arvense (L.) Scop. var. argenteum (Vest) Fiori | Cirsium arvense | Asteraceae
|
| CIARH | Cirsium arvense (L.) Scop. var. horridum Wimmer & Grab. | Cirsium arvense | Asteraceae
|
| CIARI2 | Cirsium arvense (L.) Scop. var. integrifolium Wimmer & Grab. | Cirsium arvense | Asteraceae
|
| CIARM | Cirsium arvense (L.) Scop. var. mite Wimmer & Grab. | Cirsium arvense | Asteraceae
|
| CIARV | Cirsium arvense (L.) Scop. var. vestitum Wimmer & Grab. | Cirsium arvense | Asteraceae
|
| CIAR4 | Cirsium arvense (L.) Scop. | Canada thistle | Asteraceae
|
| CIBA | Cirsium barnebyi Welsh & Neese | Barneby's thistle | Asteraceae
|
| CIBI2 | Cirsium bigelovii DC. | Cirsium muticum | Asteraceae
|
| CIBI | Cirsium bipinnatum (Eastw.) Rydb. | Cirsium calcareum | Asteraceae
|
| CIBL | Cirsium blumeri Petrak | Cirsium wheeleri | Asteraceae
|
| CIBO3 | Cirsium botrys Petrak | Cirsium ciliolatum | Asteraceae
|
| CIBR | Cirsium brevifolium Nutt. | Palouse thistle | Asteraceae
|
| CIBR2 | Cirsium brevistylum Cronq. | clustered thistle | Asteraceae
|
| CIBRL | Cirsium breweri (Gray) Jepson var. lanosissimum Petrak p.p. | Cirsium douglasii var. breweri | Asteraceae
|
| CIBRW | Cirsium breweri (Gray) Jepson var. wrangelii Petrak | Cirsium douglasii var. douglasii | Asteraceae
|
| CIBR4 | Cirsium breweri (Gray) Jepson | Cirsium douglasii var. breweri | Asteraceae
|
| CIBU3 | Cirsium butleri (Rydb.) Petrak | Cirsium scariosum var. scariosum | Asteraceae
|
| CICAB2 | Cirsium calcareum (M.E. Jones) Woot. & Standl. var. bipinnatum (Eastw.) Welsh | Cirsium calcareum | Asteraceae
|
| CICAP2 | Cirsium calcareum (M.E. Jones) Woot. & Standl. var. pulchellum (Greene) Welsh | Cirsium calcareum | Asteraceae
|
| CICA10 | Cirsium calcareum (M.E. Jones) Woot. & Standl. | Cainville thistle | Asteraceae
|
| CICAP3 | Cirsium californicum Gray ssp. pseudoreglense Petrak | Cirsium occidentale var. californicum | Asteraceae
|
| CICAB | Cirsium californicum Gray var. bernardinum (Greene) Petrak | Cirsium occidentale var. californicum | Asteraceae
|
| CICA3 | Cirsium californicum Gray | Cirsium occidentale var. californicum | Asteraceae
|
| CICAO | Cirsium callilepis (Greene) Jepson var. oregonense (Petrak) J.T. Howell | Cirsium remotifolium ssp. oregonense | Asteraceae
|
| CICAP | Cirsium callilepis (Greene) Jepson var. pseudocarlinoides (Petrak) J.T. Howell | Cirsium remotifolium ssp. pseudocarlinoides | Asteraceae
|
| CICA4 | Cirsium callilepis (Greene) Jepson | Cirsium remotifolium ssp. remotifolium | Asteraceae
|
| CICA5 | Cirsium campylon H.K. Sharsmith | Cirsium fontinale var. campylon | Asteraceae
|
| CICA12 | Cirsium candidissimum (Greene) A. Davids. & Moxley | Cirsium pastoris | Asteraceae
|
| CICA11 | Cirsium canescens Nutt. | prairie thistle | Asteraceae
|
| CICA6 | Cirsium canovirens (Rydb.) Petrak | graygreen thistle | Asteraceae
|
| CICA16 | Cirsium canum (L.) All. | Queen Anne's thistle | Asteraceae
|
| CICA7 | Cirsium carolinianum (Walt.) Fern. & Schub. | soft thistle | Asteraceae
|
| CICE | Cirsium centaureae (Rydb.) K. Schum. | Cirsium remotifolium ssp. oregonense | Asteraceae
|
| CICH2 | Cirsium chellyense Moore & Frankton | queen thistle | Asteraceae
|
| CICH3 | Cirsium chuskaense Moore & Frankton | monarch thistle | Asteraceae
|
| CICI | Cirsium ciliolatum (Henderson) J.T. Howell | Ashland thistle | Asteraceae
|
| CICL | Cirsium clavatum (M.E. Jones) Petrak | Fish Lake thistle | Asteraceae
|
| CICL2 | Cirsium clokeyi Blake | whitespine thistle | Asteraceae
|
| CICO5 | Cirsium coccinatum Osterhout | Cirsium drummondii | Asteraceae
|
| CICOA | Cirsium coloradense (Rydb.) Cockerell ssp. acaulescens (Rydb.) Petrak | Cirsium tioganum var. tioganum | Asteraceae
|
| CICOL | Cirsium coloradense (Rydb.) Cockerell ssp. longissimum (Heller) Petrak | Cirsium tioganum var. tioganum | Asteraceae
|
| CICO2 | Cirsium coloradense (Rydb.) Cockerell | Cirsium tioganum var. coloradense | Asteraceae
|
| CICO3 | Cirsium congdonii Moore & Frankton | rosette thistle | Asteraceae
|
| CICO6 | Cirsium coulteri Harvey & Gray | Cirsium occidentale var. occidentale | Asteraceae
|
| CICR | Cirsium crassicaule (Greene) Jepson | slough thistle | Asteraceae
|
| CICY | Cirsium cymosum (Greene) J.T. Howell | peregrine thistle | Asteraceae
|
| CIDA | Cirsium davisii Cronq. | Cirsium subniveum | Asteraceae
|
| CIDI2 | Cirsium diffusum (Eastw.) Rydb. | Cirsium rothrockii | Asteraceae
|
| CIDI | Cirsium discolor (Muhl. ex Willd.) Spreng. | field thistle | Asteraceae
|