| Scientific Name | Notes | Rarity Ranks | Common Name |
|---|---|---|---|
| Acaena californica | (formerly A. pinnatifida var. californica) | CNPS-EB: C | California acaena |
| Acmispon strigosus | CNPS-EB: B | strigose trefoil | |
| Alnus rubra | (A. rhombifolia is more common | CNPS-EB: A2 | red alder |
| Amelanchier utahensis | CNPS-EB: C | Utah service-berry | |
| Apocynum androsaemifolium | CNPS-EB: A2 | bitter dogbane, dogbane | |
| Aralia californica | CNPS-EB: B-PV | elk clover | |
| Arbutus menziesii | CNPS-EB: C | Pacific madrone | |
| Arctostaphylos crustacea subsp. crustacea | CNPS-EB: C | brittleleaf manzanita | |
| Arctostaphylos pallida | CNPS-EB: *A2 State CNPS: 1B.1 Global Rank: G1 CNDDB Rank: S1 FESA Status: FT CESA Status: CE | pallid manzanita | |
| Asarum caudatum | CNPS-EB: B | wild-ginger | |
| Calamagrostis rubescens | CNPS-EB: A2 | pine reed grass, pine grass | |
| Calochortus umbellatus | CNPS-EB: *A2 State CNPS: 4.2 Global Rank: G3? CNDDB Rank: S3? | Oakland star-tulip | |
| Calycadenia multiglandulosa | CNPS-EB: A2 | sticky calycadenia | |
| Camissoniopsis micrantha | CNPS-EB: B-PV | small primrose | |
| Carex barbarae | CNPS-EB: C | whiteroot sedge, Santa Barbara sedge, St. Barbara's sedge | |
| Carex densa | CNPS-EB: B | dense sedge | |
| Carex globosa | CNPS-EB: B | round-fruited sedge | |
| Carex leptopoda | (formerly Carex deweyana subsp leptopoda | CNPS-EB: A2 | slender-footed sedge, short-scaled sedge |
| Carex obnupta | CNPS-EB: B | slough sedge | |
| Carex praegracilis | CNPS-EB: C | black creeper sedge, freeway sedge, deer-bed sedge | |
| Carex subbracteata | CNPS-EB: B | small-bracted sedge | |
| Castilleja subinclusa subsp. franciscana | CNPS-EB: A1 | Franciscan indian paintbrush | |
| Castilleja wightii | CNPS-EB: B | Wight's indian paintbrush | |
| Ceanothus thyrsiflorus var. thyrsiflorus | CNPS-EB: B | blue blossom, California lilac | |
| Chrysolepis chrysophylla var. minor | CNPS-EB: A2 | golden chinquapin | |
| Cirsium brevistylum | CNPS-EB: B | indian thistle | |
| Clarkia franciscana | CNPS-EB: *A1 State CNPS: 1B.1 Global Rank: G1 CNDDB Rank: S1 FESA Status: FE CESA Status: CE | Presidio clarkia | |
| Clarkia gracilis subsp. gracilis | CNPS-EB: C | summer's darling | |
| Claytonia exigua subsp. exigua | CNPS-EB: C | common montia | |
| Clematis ligusticifolia | CNPS-EB: C | western virgin's bower, virgin's bower | |
| Corallorhiza maculata var. maculata | (forma immaculata is more comm | CNPS-EB: A2 | spotted coralroot |
| Cornus sericea subsp. sericea | CNPS-EB: C | American dogwood | |
| Crocanthemum scoparium var. vulgare | (formerly Helianthemum scoparium var. vulgare) | CNPS-EB: B | peak rush-rose |
| Cryptantha clevelandii var. florosa | CNPS-EB: A2 | Cleveland's cryptantha | |
| Cryptantha torreyana var. pumila | CNPS-EB: B | Torrey's cryptantha | |
| Cuscuta pacifica var. pacifica | (formerly C. salina var. major) | CNPS-EB: C | salt-marsh dodder |
| Cyperus erythrorhizos | CNPS-EB: B | red-rooted cyperus | |
| Danthonia californica | CNPS-EB: B-PV | California oat grass | |
| Deinandra corymbosa | (formerly Hemizonia corymbosa) | CNPS-EB: A2 | coast tarweed |
| Delphinium nudicaule | CNPS-EB: C | red larkspur, orange larkspur | |
| Deschampsia cespitosa subsp. cespitosa | CNPS-EB: B-PV | tufted hairgrass | |
| Deschampsia elongata | CNPS-EB: B-PV | slender hair grass | |
| Dirca occidentalis | CNPS-EB: *A2 State CNPS: 1B.2 Global Rank: G2 CNDDB Rank: S2 | western leatherwood | |
| Elymus multisetus | CNPS-EB: B-PV | big squirreltail | |
| Eragrostis hypnoides | CNPS-EB: A2 | ||
| Eriogonum gracile var. gracile | CNPS-EB: C | slender woolly wild buckwheat, slender buckwheat | |
| Eriogonum luteolum var. caninum | CNPS-EB: *A2 State CNPS: 1B.2 Global Rank: G5T2 CNDDB Rank: S2 | Tiburon buckwheat | |
| Festuca californica | CNPS-EB: B-PV | California fescue | |
| Festuca idahoensis | CNPS-EB: B-PV | Idaho fescue, blue bunchgrass | |
| Festuca octoflora | CNPS-EB: A2 | sixweeks grass, slender fescue | |
| Festuca rubra | CNPS-EB: B-PV | red fescue | |
| Fritillaria liliacea | CNPS-EB: *A2 State CNPS: 1B.2 Global Rank: G2 CNDDB Rank: S2 | fragrant fritillary | |
| Galium triflorum | CNPS-EB: B | sweet-scented bedstraw | |
| Garrya elliptica | CNPS-EB: B-PV | silk tassel bush | |
| Gilia capitata subsp. staminea | CNPS-EB: B-PV | blue field gilia | |
| Glycyrrhiza lepidota | CNPS-EB: C | wild licorice | |
| Gutierrezia californica | CNPS-EB: B-PV | California matchweed | |
| Helianthella castanea | CNPS-EB: *A2 State CNPS: 1B.2 Global Rank: G2 CNDDB Rank: S2 | Diablo helianthella | |
| Heterotheca sessiliflora subsp. bolanderi | (H. s. ssp. echioides is more | CNPS-EB: C | Bolander goldenaster |
| Hordeum jubatum subsp. jubatum | CNPS-EB: A2 | foxtail barley, squirreltail barley | |
| Hosackia stipularis var. stipularis | CNPS-EB: A1 | stipulate lotus | |
| Iris douglasiana | CNPS-EB: B | Douglas iris | |
| Juncus phaeocephalus var. phaeocephalus | CNPS-EB: B | brownheaded rush | |
| Koeleria macrantha | CNPS-EB: B-PV | june grass | |
| Layia chrysanthemoides | CNPS-EB: A2 | smooth layia | |
| Layia platyglossa | CNPS-EB: B-PV | tidy-tips | |
| Leptosiphon aureus | (formerly L.acicularis, Linanthus acicularis) | CNPS-EB: *A2 State CNPS: 4.2 Global Rank: G4? CNDDB Rank: S4? | bristly leptosiphon, bristly linanthus |
| Lilium pardalinum subsp. pardalinum | CNPS-EB: A1 | leopard lily | |
| Lomatium caruifolium var. caruifolium | CNPS-EB: B | caraway-leaved lomatium | |
| Luzula macrantha | CNPS-EB: C | ||
| Madia exigua | CNPS-EB: C | ||
| Marah oregana | CNPS-EB: B | coast man-root | |
| Melica californica | CNPS-EB: B-PV | California melic | |
| Mentha canadensis | CNPS-EB: B | American cornmint, Japanese peppermint | |
| Muilla maritima | CNPS-EB: B | common muilla | |
| Navarretia mellita | CNPS-EB: C | honey-scented navarretia | |
| Nuttallanthus texanus | CNPS-EB: A2 | blue toadflax | |
| Oxalis oregana | CNPS-EB: A1 | redwood sorrel | |
| Oxalis pilosa | (formerly O. albicans ssp. p.) | CNPS-EB: B | hairy wood-sorrel |
| Pentachaeta alsinoides | CNPS-EB: B-PV | tiny pentachaeta | |
| Persicaria punctata | (formerly Polygonum punctatum) | CNPS-EB: C | water smartweed |
| Petunia parviflora | CNPS-EB: A1 | wild petunia | |
| Piperia elegans subsp. elegans | CNPS-EB: C | coast piperia, elegant piperia | |
| Piperia elongata | CNPS-EB: C | chaparral orchid, wood rein-orchid, elongate piperia | |
| Piperia transversa | CNPS-EB: B | flat spurred piperia, transverse piperia | |
| Polypodium scouleri | CNPS-EB: A1 | leather-leaf fern | |
| Prunus ilicifolia subsp. ilicifolia | CNPS-EB: B | islay, holly-leafed cherry | |
| Prunus subcordata | CNPS-EB: C | Pacific plum, Sierra plum | |
| Pseudognaphalium beneolens | (formerly Gnaphalium canescens | CNPS-EB: C | fragrant everlasting |
| Pseudognaphalium biolettii | (formerly Gnaphalium bicolor) | CNPS-EB: A1 | Bioletti's cudweed |
| Quercus garryana var. garryana | CNPS-EB: B | Oregon oak | |
| Quercus parvula var. shrevei | CNPS-EB: A1 | island scrub oak | |
| Rhamnus crocea | CNPS-EB: B-PV | spiny redberry | |
| Ribes divaricatum var. pubiflorum | CNPS-EB: C | straggle bush, straggly gooseberry | |
| Ribes malvaceum var. malvaceum | CNPS-EB: C | chaparral currant | |
| Rorippa palustris subsp. palustris | CNPS-EB: B | marsh yellow-cress | |
| Rosa spithamea | CNPS-EB: C | coast ground rose, ground rose | |
| Rumex transitorius | CNPS-EB: B | willow dock | |
| Sambucus racemosa var. racemosa | CNPS-EB: B | red elderberry | |
| Sanicula laciniata | CNPS-EB: A2 | coast sanicle | |
| Scirpus microcarpus | CNPS-EB: C | small-fruited bulrush | |
| Senecio aronicoides | CNPS-EB: B-PV | rayless ragwort, California butterweed | |
| Sequoia sempervirens | CNPS-EB: B | coast redwood | |
| Silene laciniata subsp. californica | (formerly Silene c.) | CNPS-EB: C | Indian pink, California pink, California Indian pink |
| Stebbinsoseris heterocarpa | CNPS-EB: C | grassland silverpuffs, derived microseris | |
| Stipa lepida | CNPS-EB: B-PV | foothill needlegrass | |
| Stipa pulchra | CNPS-EB: B-PV | purple needlegrass | |
| Streptanthus albidus subsp. peramoenus | CNPS-EB: *A2 State CNPS: 1B.2 Global Rank: G2T2 CNDDB Rank: S2 | most beautiful jewel-flower | |
| Streptanthus glandulosus subsp. glandulosus | CNPS-EB: B-PV | jewelflower | |
| Stylocline gnaphaloides | CNPS-EB: B | everlasting neststraw, nest-straw | |
| Tellima grandiflora | CNPS-EB: C | fringe cups | |
| Trifolium depauperatum var. depauperatum | (vars. amplectens and truncatu | CNPS-EB: B | dwarf sack clover |
| Trifolium fucatum | CNPS-EB: B | bull clover | |
| Trifolium oliganthum | CNPS-EB: C | few-flowered clover | |
| Triglochin concinna var. concinna | (T. maritima is more common) | CNPS-EB: A1 | seaside arrow-grass, slender arrow-grass |
| Triglochin maritima | CNPS-EB: C | common arrow-grass, seaside arrow-grass | |
| Trillium ovatum subsp. ovatum | CNPS-EB: A2 | white trillium | |
| Vaccinium ovatum | CNPS-EB: B-PV | California huckleberry | |
| Viola adunca subsp. adunca | CNPS-EB: A1 | western blue violet | |
| Viola sempervirens | CNPS-EB: A2 | evergreen violet, redwood violet | |
| Wyethia glabra | (W. helenioides is more common | CNPS-EB: C | mule ears |
| Zeltnera davyi | (formerly Centaurium d.) | CNPS-EB: B | Davy's centaury, conchalagua |
| Abronia latifolia | (historical-1894) | CNPS-EB: A1x | yellow sand-verbena |
| Abronia umbellata var. umbellata | (historical-1937) | CNPS-EB: A1x | beach sand-verbena |
| Adiantum aleuticum | (A. jordanii is more common) | CNPS-EB: A1 | five-finger fern |
| Agoseris heterophylla var. heterophylla | CNPS-EB: C | ||
| Agrostis hallii | CNPS-EB: A2 | Hall's bent grass | |
| Allium falcifolium | CNPS-EB: A2 | sickle-leaved onion | |
| Ambrosia chamissonis | CNPS-EB: C | beach bur-sage, beach-bur | |
| Ammannia coccinea | CNPS-EB: A2 | long-leaved ammannia | |
| Apiastrum angustifolium | CNPS-EB: C | wild celery | |
| Apocynum cannabinum | CNPS-EB: B | dogbane, Indian-hemp | |
| Arctostaphylos glandulosa subsp. glandulosa | CNPS-EB: A2 | Eastwood manzanita | |
| Arnica discoidea | CNPS-EB: B | rayless arnica | |
| Astragalus nuttallii var. virgatus | (historical-1881) | CNPS-EB: A1x | Nuttall's milk-vetch |
| Astragalus tener var. tener | CNPS-EB: *A2 State CNPS: 1B.2 Global Rank: G2T1 CNDDB Rank: S1 | alkali milkvetch | |
| Atriplex dioica | (formerly A. subspicata) | CNPS-EB: A1x | thickleaf orach, saltbush |
| Atriplex gmelinii var. gmelinii | (historical-1897) | CNPS-EB: A1x | Gmelin's saltbush, spear saltbush |
| Atriplex leucophylla | CNPS-EB: B | beach saltbush | |
| Balsamorhiza macrolepis | CNPS-EB: *A1 State CNPS: 1B.2 Global Rank: G2 CNDDB Rank: S2 | big-scale balsamroot | |
| Brodiaea terrestris subsp. terrestris | CNPS-EB: B-PV | dwarf brodiaea | |
| Bromus sitchensis var. maritimus | (formerly B. maritimus) | CNPS-EB: A1 | maritime brome, seaside brome grass |
| Calamagrostis nutkaensis | (historical-18??) | CNPS-EB: A1x | Pacific reed grass |
| California macrophylla | (formerly Erodium macrophyllum | CNPS-EB: B-PV | round-leaved filaree |
| Camissoniopsis cheiranthifolia subsp. cheiranthifolia | CNPS-EB: A1 | dune suncup | |
| Carex multicostata | CNPS-EB: A1 | many-ribbed sedge | |
| Carex nudata | CNPS-EB: B | torrent sedge | |
| Carex senta | CNPS-EB: A1 | western rough sedge, rough sedge | |
| Castilleja ambigua subsp. ambigua | CNPS-EB: *A2 State CNPS: 4.2 Global Rank: G5T4 CNDDB Rank: S3S4 | Johnny-nip | |
| Castilleja exserta subsp. latifolia | CNPS-EB: A1 | owl's-clover | |
| Castilleja rubicundula subsp. lithospermoides | CNPS-EB: B | cream sacs | |
| Chenopodium rubrum | CNPS-EB: A1 | red pigweed, red goosefoot | |
| Chloropyron maritimum subsp. palustre | (historical-1917) | CNPS-EB: *A1x State CNPS: 1B.2 Global Rank: G4?T2 CNDDB Rank: S2 | Point Reyes salty bird's-beak |
| Chorizanthe cuspidata var. cuspidata | (historical-1881) | CNPS-EB: *A1x State CNPS: 1B.2 Global Rank: G2T1 CNDDB Rank: S1 | San Francisco Bay spineflower |
| Cicendia quadrangularis | CNPS-EB: A2 | timwort | |
| Cicuta douglasii | CNPS-EB: A2 | water-hemlock | |
| Cirsium quercetorum | CNPS-EB: A2 | brownie thistle | |
| Clarkia concinna subsp. concinna | CNPS-EB: C | large godetia | |
| Clintonia andrewsiana | CNPS-EB: A1 | red clintonia | |
| Corallorhiza striata | (C. maculata is more common) | CNPS-EB: A1x | striped coralroot |
| Corethrogyne filaginifolia | (formerly Lessingia f. var. f. | CNPS-EB: C | California aster |
| Cornus sericea subsp. unknown | CNPS-EB: C? | American dogwood | |
| Crassula aquatica | CNPS-EB: B | water pygmy-weed | |
| Dendromecon rigida | CNPS-EB: A2 | bush poppy | |
| Deschampsia cespitosa subsp. holciformis | CNPS-EB: B | tufted hairgrass | |
| Deschampsia danthonioides | CNPS-EB: B-PV | annual hair grass | |
| Dichelostemma volubile | 2 questionable ID sites. Needs field research | CNPS-EB: A1? | twining brodiaea, snake lily |
| Echinodorus berteroi | CNPS-EB: A2 | burhead | |
| Elymus mollis subsp. mollis | CNPS-EB: A1x | American dune grass, sea lyme grass | |
| Elymus trachycaulus subsp. trachycaulus | CNPS-EB: A1 | slender wheat grass | |
| Epilobium ciliatum subsp. watsonii | (ssp. ciliatum is more common) | CNPS-EB: A1 | San Francisco willowherb |
| Eragrostis mexicana subsp. virescens | CNPS-EB: A1 | Orcutt's eragrostis | |
| Eriogonum fasciculatum var. foliolosum | CNPS-EB: A1 | leafy California buckwheat, California buckwheat | |
| Erythranthe microphylla | CNPS-EB: A1x | ||
| Extriplex californica | (historical-1921) | CNPS-EB: A1x | California orach, California saltbush |
| Extriplex joaquinana | CNPS-EB: *A2 State CNPS: 1B.2 Global Rank: G2 CNDDB Rank: S2 | San Joaquin spearscale, San Joaquin saltbush | |
| Festuca elmeri | CNPS-EB: A1 | Elmer's fescue | |
| Gaultheria shallon | CNPS-EB: A1 | salal | |
| Gilia capitata subsp. unknown | CNPS-EB: A1? | blue field gilia | |
| Gilia millefoliata | CNPS-EB: *A1x State CNPS: 1B.2 Global Rank: G2 CNDDB Rank: S2 | DARK-EYED GILIA | |
| Helianthus californicus | CNPS-EB: B | California sunflower | |
| Hemizonia congesta subsp. lutescens | CNPS-EB: B | hayfield tarweed | |
| Hesperomecon linearis | (formerly Meconella l.) (hist | CNPS-EB: A1x | narrow-leaved meconella |
| Hieracium albiflorum | CNPS-EB: C | white hawkweed | |
| Hoita macrostachya | CNPS-EB: B | California hemp | |
| Hoita orbicularis | (historical-1936) | CNPS-EB: A1x | round-leaved psoralea |
| Horkelia cuneata var. sericea | (historical-1894) | CNPS-EB: *A1x State CNPS: 1B.1 Global Rank: G4T1? CNDDB Rank: S1? | Kellogg's horkelia |
| Iris longipetala | CNPS-EB: *A1 State CNPS: 4.2 Global Rank: G3 CNDDB Rank: S3 | coast iris | |
| Isolepis cernua | (formerly Scirpus cernuus) | CNPS-EB: C | low club-rush |
| Juncus phaeocephalus var. paniculatus | CNPS-EB: B | panicled rush, brown-headed rush | |
| Juncus phaeocephalus var. unknown | CNPS-EB: A2? | brown-headed rush | |
| Lasthenia glabrata subsp. glabrata | CNPS-EB: A2 | yellow-ray goldfields | |
| Lathyrus jepsonii var. californicus | CNPS-EB: B | buff pea | |
| Layia gaillardioides | CNPS-EB: A2 | woodland layia | |
| Layia glandulosa | (historical-1983 but not seen | CNPS-EB: A1x | white layia |
| Layia hieracioides | CNPS-EB: B-PV | tall layia | |
| Lepidium oblongum | (historical-1937) | CNPS-EB: A1x | wayside pepper-grass |
| Leptosyne stillmanii | (formerly Coreopsis s.) | CNPS-EB: A1x | Stillman's coreopsis |
| Lupinus littoralis var. variicolor | (formerly L. variicolor) | CNPS-EB: A1? | bluff lupine |
| Madia anomala | CNPS-EB: A1x | plump-seeded madia | |
| Micropus amphibolus | (historical - 1955) | CNPS-EB: *A1x State CNPS: 3.2 Global Rank: G3G4 CNDDB Rank: S3S4 | Mount Diablo cottonseed, Mt. Diablo cottonweed |
| Microseris bigelovii | (historical-1891) | CNPS-EB: A1x | coast microseris |
| Monardella douglasii | CNPS-EB: A2 | fenestra monardella, Fenestra monardella | |
| Monolopia gracilens | CNPS-EB: *A2 State CNPS: 1B.2 Global Rank: G3 CNDDB Rank: S3 | woodland woollythreads, woodland monolopia | |
| Morella californica | (formerly Myrica c.) | CNPS-EB: B | wax myrtle |
| Myriopteris gracillima | CNPS-EB: A1 | lace fern | |
| Panicum capillare | CNPS-EB: A2 | witch grass | |
| Perideridia oregana | CNPS-EB: A2 | yampah | |
| Persicaria lapathifolia | (formerly Polygonum lapathifol | CNPS-EB: B | willow weed |
| Phacelia divaricata | CNPS-EB: B-PV | divaricate phacelia | |
| Phacelia tanacetifolia | CNPS-EB: B | tansy phacelia | |
| Phalaris angusta | (historical-1912) | CNPS-EB: A1x | narrow canary grass |
| Phalaris lemmonii | CNPS-EB: A1 | Lemmon's canary-grass | |
| Phoradendron leucarpum subsp. macrophyllum | (formerly P. serotinum subsp. macrophyllum, P. macrophyllum) | CNPS-EB: C | big leaf mistletoe |
| Piperia unalascensis | CNPS-EB: A1 | Alaska piperia, slender-spire orchid | |
| Plagiobothrys canescens var. canescens | CNPS-EB: C | valley popcornflower | |
| Plagiobothrys chorisianus var. chorisianus | (historical-1890) | CNPS-EB: *A1x State CNPS: 1B.2 Global Rank: G3T1Q CNDDB Rank: S1 | Choris' popcornflower |
| Plagiobothrys trachycarpus | CNPS-EB: C | rough-nutlet popcornflower, rough-fruited allocarya | |
| Plantago elongata | CNPS-EB: B-PV | annual coast plantain | |
| Platanus racemosa | CNPS-EB: C | western sycamore, California sycamore | |
| Pleuropogon californicus var. californicus | CNPS-EB: B-PV | semaphore grass | |
| Poa douglasii | (historical-1882) | CNPS-EB: A1x | sanddune bluegrass |
| Poa howellii | CNPS-EB: A2 | Howell's bluegrass | |
| Polygonum marinense | CNPS-EB: *A1x State CNPS: 3.1 Global Rank: G2Q CNDDB Rank: S2 | MARIN KNOTWEED | |
| Polystichum californicum | CNPS-EB: A1 | California sword fern | |
| Polystichum imbricans subsp. imbricans | CNPS-EB: A1x | rock sword fern | |
| Populus trichocarpa | (formerly P. balsamifera var. | CNPS-EB: C | black cottonwood |
| Prosartes smithii | (formerly Disporum s.)(P. | CNPS-EB: A1x | large-flowered fairy bell |
| Prunella vulgaris var. lanceolata | (var. vulgaris is more common) | CNPS-EB: B | selfheal |
| Prunus emarginata | CNPS-EB: C | bitter cherry | |
| Psilocarphus chilensis | (formerly P. tenellus var. glo | CNPS-EB: A1 | round woolly marbles, round woolly-marbles |
| Quercus lobata | CNPS-EB: C | valley oak, roble | |
| Quercus wislizeni var. frutescens | CNPS-EB: C | shrubby interior live oak | |
| Ranunculus orthorhynchus var. bloomeri | CNPS-EB: A1x | Bloomer's buttercup | |
| Ribes amarum | CNPS-EB: A1? | bitter gooseberry | |
| Ribes speciosum | CNPS-EB: A1 | fuchsia-flowered gooseberry | |
| Rumex fueginus | CNPS-EB: A2 | golden dock | |
| Rumex salicifolius | (formerly R. salicifolius var. salicifolius) | CNPS-EB: B | willow dock |
| Rumex salicifolius var. unknown | CNPS-EB: A2? | willow dock | |
| Sagittaria latifolia | CNPS-EB: A1x | arrowhead | |
| Salix scouleriana | CNPS-EB: A2 | Scouler's willow | |
| Sanicula arctopoides | CNPS-EB: A1x | footsteps of spring, yellow mats | |
| Sanicula maritima | (historical-1936) | CNPS-EB: *A1x State CNPS: 1B.1 Global Rank: G2 CNDDB Rank: S2 CESA Status: CR | adobe sanicle |
| Scoliopus bigelovii | (historical-1900) | CNPS-EB: A1x | fetid adder's tongue, slink pod |
| Scutellaria californica | CNPS-EB: B | California skullcap | |
| Scutellaria tuberosa | CNPS-EB: C | Dannie's skullcap | |
| Sedum spathulifolium | CNPS-EB: B | broadleaf stonecrop, Pacific stonecrop | |
| Setaria parviflora | CNPS-EB: B | knotroot bristle grass, perennial foxtail | |
| Silene verecunda | CNPS-EB: A1 | San Francisco campion, Cuyamaca campion | |
| Spergularia macrotheca var. longistyla | CNPS-EB: *A2 State CNPS: 1B.2 Global Rank: G5T2 CNDDB Rank: S2 | large-flowered sand spurry | |
| Spergularia macrotheca var. macrotheca | CNPS-EB: A2 | large-flowered sand spurry | |
| Spiranthes porrifolia | CNPS-EB: A1x | western ladies' tresses | |
| Spiranthes romanzoffiana | CNPS-EB: A1 | hooded ladies' tresses | |
| Stachys bullata | CNPS-EB: A1? | California hedge nettle | |
| Stephanomeria elata | CNPS-EB: A1 | stephanomeria | |
| Symphyotrichum lanceolatum var. hesperium | (formerly Aster lanceolatus ss | CNPS-EB: A2 | marsh aster |
| Tetrapteron graciliflorum | CNPS-EB: B-PV | hill sun cup | |
| Thermopsis californica var. californica | (historical-1929) | CNPS-EB: A1x | santa ynez false-lupine, false-lupine |
| Thysanocarpus radians | CNPS-EB: A1 | ribbed fringe pod | |
| Trifolium barbigerum | CNPS-EB: A2 | bearded clover | |
| Trifolium dichotomum | CNPS-EB: C | branched indian clover | |
| Trifolium hydrophilum | (vars. amplectens and truncatu | CNPS-EB: *A2 State CNPS: 1B.2 Global Rank: G2 CNDDB Rank: S2 | saline clover |
| Trifolium macraei | CNPS-EB: A1 | Macrae's clover, double-headed clover | |
| Trifolium wormskioldii | CNPS-EB: A1 | cow clover | |
| Triglochin scilloides | CNPS-EB: C | flowering-quillwort | |
| Triodanis biflora | CNPS-EB: A2 | Venus' looking-glass | |
| Triphysaria versicolor subsp. faucibarbata | CNPS-EB: B | smooth owl's-clover | |
| Trisetum canescens | CNPS-EB: A2 | tall trisetum | |
| Vancouveria planipetala | (historical-1898) | CNPS-EB: A1x | redwood ivy, inside-out flower |
| Vicia hassei | CNPS-EB: A2 | slender vetch |