Quail bush (Atriplex lentiformis)
Quaking aspen (Populus tremuloides)
Quillwort, Flowering (Lilaea scilloides)
Rabbitbrush,
Black-banded (Ericameria
paniculata)
Ghostly rubber (Ericameria
nauseosa var. hololeuca)
Green (Ericameria teretifolia)
Mojave rubber (Ericameria
nauseosa ssp. mohavensis)
Parry's (Ericameria
parryi var. aspera)
San Bernardino rubber (Ericameria
nauseosa var. bernardina)
Sharp-bracted rubber (Ericameria
nauseosa var. ceruminosa
)
Sticky-leaved (Chrysothamnus
viscidiflorus ssp. viscidiflorus)
Threadleaf rubber (Ericameria
nauseosa ssp. oreophila)
White-flowered (Ericameria albida)
Rabbitsfoot grass (Polypogon monspeliensis)*
Ragged-leaf bahia (Amauriopsis dissecta)
Ragweed, Western (Ambrosia psilostachya)
Ragwort,
Dwarf mountain (Senecio fremontii var. occidentalis)
Mojave (Senecio
mohavensis)
San Bernardino (Packera
bernardina)
Tehachapi (Packera
ionophylla)
Raillardella, Silky (Raillardella argentea)
Ramona clarkia (Clarkia similis)
Ramona horkelia (Horkelia truncata)
Ranger's buttons (Sphenosciadium
capitellatum)
Raspberry, Western (Rubus leucodermis)
Rattail fescue, Hairy (Vulpia myuros var. hirsuta)*
Rattlesnake weed (Chamaesyce
albomarginata)
Rattleweed,
Braunton's (Astragalus
brauntonii)
Newberry's (Astragalus
newberryi var. newberryi)
Rayless encelia (Encelia frutescens)
Rayless fleabane (Erigeron
aphanactis var. congestus)
Rayless goldfields (Lasthenia glaberrima)
Red ammannia (Ammannia
coccinea)
Red baneberry (Actaea rubra)
Red brome (Bromus madritensis ssp. rubens)*
Red clover (Trifolium pratense)*
Red elderberry (Sambucus racemosa var.
racemosa)
Red four o'clock (Mirabilis coccinea)
Red grama (Bouteloua trifida)
Red iceplant (Malephora crocea)*
Red maids,
Brewer's (Calandrinia
breweri)
[Common] (Calandrinia
ciliata)
Seaside (Cistanthe
maritima)
Red mariposa lily (Calochortus
kennedyi var. kennedyi)
Red monardella (Monardella macrantha ssp.
hallii)
Red Rock tarplant (Deinandra arida)
Red sand verbena (Abronia maritima)
Red shanks (Adenostoma
sparsifolium)
Red thistle (Cirsium arizonicum var. tenuisectum)
Red valerian (Centranthus ruber)*
Red willow (Salix laevigata)
Redberry,
Hollyleaf (Rhamnus
ilicifolia)
Island (Rhamnus
pirifolia)
Littleleaf (Rhamnus
crocea)
Redbud, Western (Cercis
occidentalis)
Red-flowered buckwheat (Eriogonum
grande var. rubescens)
Red-gland spurge (Chamaesyce melanadenia)
Red-rayed hulsea (Hulsea heterochroma)
Red-skinned onion (Allium
haematochiton)
Red-stem filaree (Erodium cicutarium)*
Red-stemmed monkeyflower (Mimulus
rubellus)
Reflexed blazing star (Mentzelia
reflexa)
Rein orchid,
Alaska (Piperia
unalascensis)
[Common] (Piperia
cooperi)
Dense-flowered (Piperia
elongata)
Royal (Piperia
transversa)
Retrorse desert four o'clock (Mirabilis
laevis var. retrorsa)
Reveal's buckwheat (Eriogonum contiguum)
Rhatany,
Littleleaf (Krameria
erecta)
White (Krameria
grayi)
Rhubarb, Wild (Rumex hymenosepalus)
Ribbed cryptantha (Cryptantha costata)
Ricegrass, Indian (Stipa hymenoides)
Rigid hedge nettle (Stachys ajugoides
var. rigida)
Rigid spineflower (Chorizanthe rigida)
Ringstem, Sticky (Anulocaulis annulatus)
Ripgut brome (Bromus diandrus)*
River bar bird's-foot trefoil (Acmispon denticulatus)
Riverside spineflower (Chorizanthe xanti var. leucotheca)
Rixford's buckwheat (Eriogonum rixfordii)
Rixford's rockwort (Scopulophila rixfordii)
Robust sun cup (Camissoniopsis robusta)
Robust vervain (Verbena lasiostachys var.
scabrida)
Rock buckwheat (Eriogonum saxatile)
Rock Creek broom-rape (Orobanche
valida ssp. valida)
Rock crossosoma (Crossosoma bigelovii)
Rock daisy (Perityle
emoryi)
Rock dudleya (Dudleya
saxosa ssp. aloides)
Rock gilia (Gilia scopulorum)
Rock goldenbush (Ericameria
cuneata var. cuneata)
Rock hibiscus (Hibiscus denudatus)
Rock ivesia (Ivesia saxosa)
Rock pennyroyal (Monardella robisonii)
Rock phacelia (Phacelia egena)
Rock spiraea (Petrophyton caespitosum)
Rock-cress,
Arched elegant (Boechera arcuata)
Beautiful (Boechera pulchra)
Bristly-leaved (Boechera
rectissima)
Broad-seeded (Boechera platysperma)
Elegant (Boechera californica)
Parish's (Boechera
parishii)
Perennial (Boechera
perennans)
Pine (Boechera pinetorum)
Shockley's (Boechera
shockleyi)
Slender beautiful (Boechera xylopoda)
Yosemite (Boechera repanda)
Rockjasmine monkeyflower (Mimulus androsaceus)
Rocknettle, Desert (Eucnide urens)
Rock-rose,
Crimson spot (Cistus
ladanifer var. maculatus)*
Orchid (Cistus
Xpurpureus)*
Pink (Cistus incanus)*
White-flowered (Cistus
ladanifer var. albiflorus)*
Rockwort, Rixford's (Scopulophila rixfordii)
Rocky Mountain buttercup (Ranunculus
cymbalaria var. saximontanus)
Rocky Mountain rush (Juncus saximontanus)
Ropevine (Clematis pauciflora)
Rose,
Cliff (Purshia mexicana
var. stansburyana)
Interior (Rosa
woodsii var. ultramontana)
Small-leaved (Rosa
minutifolia)
Wild (Rosa
californica)
Wood (Rosa gymnocarpa)
Rose clover (Trifolium hirtum)*
Rose evening primrose (Oenothera
rosea)*
Rose heath (Chaetopappa ericoides)
Rose sage (Salvia pachyphylla)
Rose snapdragon (Antirrhinum multiflorum)
Ross's sedge (Carex rossii)
Rosy apricot mallow (Sphaeralcea ambigua var. rosacea)
Rosy gilia (Gilia sinuata)
Rosy pussytoes (Antennaria rosea ssp.
confinis)
Rosy spinystar (Coryphantha vivipara var rosea)
Rothrock's keckiella (Keckiella rothrockii
var. rothrockii)
Rothrock's nama (Nama rothrockii)
Rothrock's sagebrush (Artemisia rothrockii)
Rough cat's ear (Hypochaeris radicata)*
Rough joint-fir (Ephedra aspera)
Rough menodora (Menodora scabra)
Roughseed cryptantha (Cryptantha flavoculata)
Roundleaf geranium (Geranium rotundifolium)*
Roundleaf leather root (Hoita orbicularis)
Roundleaf oxytheca (Oxytheca perfoliata)
Round-leaved boykinia (Boykinia
rotundifolia)
Round-leaved phacelia (Phacelia
rotundifolia)
Royal desert lupine (Lupinus
odoratus)
Royal goldfields (Lasthenia coronaria)
Royal penstemon (Penstemon speciosus)
Royal rein orchid (Piperia transversa)
Rubber rabbitbrush,
Ghostly (Ericameria
nauseosa var. hololeuca)
Mojave (Chrysothamnus
nauseosus ssp. mohavensis)
San Bernardino (Ericameria
nauseosa var. bernardina)
Sharp-bracted (Ericameria
nauseosa var. ceruminosa)
Threadleaf (Chrysothamnus
nauseosus ssp. consimilis)
Rusby's desert mallow (Sphaeralcea rusbyi var. eremicola)
Rush,
Basket (Juncus textilis)
Brown-headed (Juncus
phaeocephalus var. paniculatus)
Common toad (Juncus
bufonius var. bufonius)
Clustered toad (Juncus
bufonius var. congestus)
Iris-leaved (Juncus
xiphioides)
Long-anthered (Juncus
macrandus)
Long-leaved (Juncus
macrophyllus)
Mariposa (Juncus
dubius)
Mexican (Juncus
mexicanus)
Moss (Juncus bryoides)
Pacific (Juncus
effusus var. pacificus)
Pacific wood (Luzula
comosa)
Rocky Mountain (Juncus saximontanus)
Spiny (Juncus acutus
ssp. leopoldii)
Spreading (Juncus
patens)
Tiehm's (Juncus tiehmii)
Western toad (Juncus
bufonius var. occidentalis)
Wire (Juncus balticus)
Wrinkled (Juncus
rugulosus)
Rush bluegrass (Poa secunda ssp. juncifolia)
Rush milkweed (Asclepias
subulata)
Rush seepweed (Suaeda moquinii)
Rush-rose (Helianthemum
scoparium)
Russian knapweed (Acroptilon repens)*
Russian thistle (Salsola tragus)*
Rusty slender sedge (Carex subfusca)
Rusty-haired popcorn flower (Plagiobothrys
nothofulvus)
Rydberg's horkelia (Horkelia rydbergii)
Ryegrass, Italian (Lolium multiflorum)*
Sacapellote (Acourtia microcephala)
Sacred datura (Datura
wrightii)
Safflower (Carthamus tinctorius)*
Sage,
Black (Salvia
mellifera)
Blue (Salvia dorrii var. dorrii)
Blue (Salvia
dorrii var. pilosa)
Brandegee's (Salvia
brandegeei)
Cleveland (Salvia
clevelandii)
Creeping (Salvia
sonomensis)
Crimson pitcher (Salvia
spathacea)
Death Valley (Salvia
funerea)
Desert (Salvia eremostachya)
Fragrant pitcher (Lepechinia
fragrans)
Munz's (Salvia munzii)
Purple (Salvia
leucophylla)
Rose (Salvia pachyphylla)
Thistle (Salvia
carduacea)
Vasey's (Salvia vaseyi)
White (Salvia
apiana)
Sagebrush,
Basin (Artemisia
tridentata ssp. tridentata)
Black (Artemisia nova)
California (Artemisia
californica)
Mountain (Artemisia
tridentata ssp. vaseyana)
Parish's (Artemisia
tridentata ssp. parishii)
Rothrock's (Artemisia
rothrockii)
Saguaro, Giant (Carnegiea gigantea)
Saharan mustard (Brassica tournefortii)*
Salsify,
Purple (Tragopogon
porrifolius)*
Yellow (Tragopogon
dubius)*
Salt cedar (Tamarix ramosissima)*
Salt grass (Distichlis spicata)
Salt marsh baccharis (Baccharis glutinosa)
Salt marsh bird's beak (Chloropyron
maritimum ssp. maritimum)
Salt marsh dodder (Cuscuta salina)
Salt marsh fleabane (Pluchea
odorata)
Salt marsh sand spurrey (Spergularia
marina)
Saltbush,
Arrowleaf (Atriplex
prostrata)*
Australian (Atriplex
semibaccata)*
Beach (Atriplex
leucophylla)
California (Atriplex
californica)
Fourwing (Atriplex
canescens var. canescens)
Fourwing (Atriplex canescens var. laciniata)
Pacific (Atriplex
pacifica)
Shadscale (Atriplex
confertifolia)
Swamp (Atriplex
amnicola)*
Watson's (Atriplex
watsonii)
Waxy (Atriplex
glauca)*
Wheelscale (Atriplex elegans var. fasciculata)
Salton milkvetch (Astragalus crotalariae)
Saltwort (Batis maritima)
San Antonio Canyon bedstraw (Galium angustifolium ssp. gabrielense)
San Bernardino aster (Symphyotrichum defoliatum)
San Bernardino beardtongue (Penstemon
caesius)
San Bernardino bluegrass (Poa
atropurpurea)
San Bernardino mountain onion (Allium
monticola)
San Bernardino Mountains alumroot (Heuchera
parishii)
San Bernardino Mountains bladderpod (Physaria kingii
ssp. bernardina)
San Bernardino Mountains dudleya (Dudleya
abramsii ssp. affinis)
San Bernardino Mountains monkeyflower (Mimulus
exiguus)
San Bernardino Mountains owl's clover (Castilleja
lasiorhyncha)
San Bernardino ragwort (Packera
bernardina)
San Bernardino rubber rabbitbrush (Ericameria
nauseosa var. bernardina)
San Bernardino sun cup (Camissoniopsis
confusa)
San Clemente Island bird's-foot trefoil (Acmispon
argophyllus var. adsurgens)
San Clemente Island bush mallow (Malacothamnus
clementinus)
San Diego ambrosia (Ambrosia pumila)
San Diego button-celery (Eryngium
aristulatum var. parishii)
San Diego County goldeneye (Bahiopsis
laciniata)
San Diego County needlegrass (Stipa
diegoensis)
San Diego gilia (Gilia diegensis)
San Diego gumplant (Grindelia hallii)
San Diego hulsea (Hulsea californica)
San Diego morning glory (Calystegia
macrostegia ssp. tenuifolia)
San Diego mountain mahogany (Cercocarpus
minutiflorus)
San Diego pea (Lathyrus vestitus var. alefeldii)
San Diego satureja (Clinopodium chandleri)
San Diego sedge (Carex spissa)
San Diego tarplant (Deinandra paniculata)
San Diego thornmint (Acanthomintha
ilicifolia)
San Diego wreathplant (Stephanomeria
diegensis)
San Felipe dyssodia (Adenophyllum
porophylloides)
San Felipe monardella (Monardella
nana) (Formerly Monardella nana ssp. leptosiphon)
San Fernando Valley spineflower (Chorizanthe
parryi var. fernandina)
San Gabriel beardtongue (Penstemon
labrosus)
San Gabriel beardtongue (yellow variant) (Penstemon
labrosus)
San Gabriel bluecup (Githopsis diffusa ssp. diffusa)
San Gabriel linanthus (Linanthus
concinnus)
San Gabriel manzanita (Arctostaphylos
glandulosa ssp. gabrielensis)
San Gabriel Mountains dudleya (Dudleya
densiflora)
San Gabriel Mountains hulsea (Hulsea
vestita ssp. gabrielensis)
San Gabriel Mountains leather oak (Quercus
durata var. gabrielensis)
San Gabriel River dudleya (Dudleya
cymosa ssp. crebifolia)
San Jacinto beardtongue (Penstemon
clevelandii var. connatus)
San Jacinto buckwheat (Eriogonum
apiculatum)
San Jacinto lupine (Lupinus hyacinthinus)
San Jacinto Mountains bedstraw (Galium
angustifolium ssp. jacinticum)
San Jacinto Mountains fleabane (Erigeron
breweri var. jacinteus)
San Jacinto Mountains keckiella (Keckiella
rothrockii var. jacintensis)
San Jacinto prickly phlox (Linanthus
jaegeri)
San Luis Obispo milkvetch (Astragalus
curtipes)
San Miguel Island bedstraw (Galium
californicum ssp. miguelense)
San Miguel Island deerweed (Acmispon
dendroideus var. veatchii)
San Miguel milkvetch (Astragalus
miguelensis)
Sand blazing star (Mentzelia
involucrata)
Sand cress (Calyptridium monandrum)
Sand food (Pholisma sonorae)
Sand gilia (Aliciella triodon)
Sand plantain (Plantago arenaria)*
Sand spikerush (Eleocharis montevidensis)
Sand spurrey,
Boccone's (Spergularia
bocconi)*
Hairy (Spergularia
villosa)*
Salt marsh (Spergularia
marina)
Sticky (Spergularia
macrotheca ssp. macrotheca)
Sand verbena,
Desert (Abronia
villosa var. aurita)
Desert (Abronia
villosa var. villosa)
Pink (Abronia
umbellata var. umbellata)
Red (Abronia
maritima)
White (Abronia
turbinata)
Sandbar willow (Salix exigua)
Sand-dune bluegrass (Poa douglasii)
Sand-lettuce (Dudleya caespitosa)
Sandmat (Cardionema ramosissimum)
Sandpaper plant (Petalonyx thurberi)
Sandpaper plant, Shinyleaf (Petalonyx nitidus)
Sandwort,
Annual (Minuartia pusilla)
Bear Valley (Eremogone
ursina)
Brittle (Minuartia nuttallii var. gracilis)
Desert (Eremogone
macradenia var. macradenia)
King's (Eremogone
kingii var. glabrescens)
Spreading (Arenaria lanuginosa var. saxosa)
Sanicle,
Pacific (Sanicula
crassicaulis)
Poison (Sanicula
bipinnata)
Purple (Sanicula
bipinnatifida)
Sierra (Sanicula
graveolens)
Santa Ana River woolstar (Eriastrum
densifolium ssp. sanctorum)
Santa Barbara Island dudleya (Dudleya
traskiae)
Santa Barbara milkvetch (Astragalus
trichopodus var. phoxus)
Santa Catalina Island ironwood (Lyonothamnus
floribundus ssp. floribundus)
Santa Catalina Island manzanita (Arctostaphylos
catalinae)
Santa Cruz Island bird's-foot trefoil (Acmispon
argophyllus var. niveus)
Santa Cruz Island buckwheat (Eriogonum
arborescens)
Santa Cruz Island gooseberry (Ribes
thacherianum)
Santa Monica Mountains manzanita (Arctostaphylos
glandulosa ssp. mollis)
Santa Rosa basalt brodiaea (Brodiaea santarosae)
Santa Rosa Island manzanita (Arctostaphylos
confertiflora)
Santa Rosa Mountains linanthus (Leptosiphon floribundus ssp. hallii)
Santa Susana tarplant (Deinandra
minthornii)
Santolina pincushion (Chaenactis
santolinoides)
Sanvitalia, Abert's (Sanvitalia abertii)
Sapphire woolstar (Eriastrum sapphirinum)
Satureja, San Diego (Clinopodium chandleri)
Savory, Monkeyflower (Clinopodium mimuloides)
Sawtooth goldenbush (Hazardia
squarrosa var. grindelioides)
Saxifrage, California (Saxifraga
californica)
Scalebroom (Lepidospartum
squamatum)
Scalebud (Anisocoma acaulis)
Scalloped moonwort (Botrychium crenulatum)
Scaly cloak fern (Astrolepis cochisensis)
Scaly-stemmed sand plant (Pholisma arenarium)
Scarlet bugler (Penstemon centranthifolius)
Scarlet gaura (Oenothera suffrutescens)
Scarlet larkspur (Delphinium
cardinale)
Scarlet lobelia (Lobelia cardinalis var. pseudosplendens)
Scarlet milkvetch (Astragalus coccineus)
Scarlet monkeyflower (Mimulus
cardinalis)
Scarlet pimpernel (Anagallis arvensis)*
Scarlet spiderling (Boerhavia coccinea)
Scented cryptantha (Cryptantha
utahensis)
Schott's calico (Loeseliastrum schottii)
Schott's indigo bush (Psorothamnus
schottii)
Scouler's St. John's wort (Hypericum
formosum var. scouleri)
Scouler's willow (Salix scouleriana)
Screwbean mesquite (Prosopis pubescens)
Scrub aster (Dieteria asteroides var. asteroides)
Scrub lotus (Acmispon argyraeus var. multicaulis)
Scrub oak,
Channel Island (Quercus
pacifica)
Coastal (Quercus
dumosa)
Desert (Quercus
john-tuckeri)
Inland (Quercus
berberidifolia)
Sea beet (Beta vulgaris ssp. maritima)
Sea dahlia (Leptosyne
maritima)
Sea fig (Carpobrotus chilensis)*
Sea rocket (Cakile maritima)*
Sea-blite,
Estuary (Suaeda
esteroa)
Woolly (Suaeda
taxifolia)
Seacliff buckwheat (Eriogonum
parvifolium)
Sea-lavender (Limonium californicum)
Sea-pink, California (Armeria maritima
ssp. californica)
Seashore bentgrass (Agrostis pallens)
Seaside brome (Bromus maritimus)
Seaside daisy (Erigeron
glaucus)
Seaside fiddleneck (Amsinckia spectabilis
var. spectabilis)
Seaside petunia (Petunia parviflora)
Seaside red maids (Cistanthe maritima)
Sedge,
Clustered field (Carex
praegracilis)
Dense (Carex densa)
Forest (Carex multicaulis)
Fragile-sheathed (Carex
fracta)
Golden (Carex aurea)
Ross's sedge (Carex rossii)
Rusty slender (Carex subfusca)
San Diego (Carex
spissa)
Smooth-fruited (Carex heteroneura)
Sturdy (Carex alma)
Swamp (Carex senta)
Tall flat (Cyperus
eragrostis)
Triangular-fruit (Carex
triquetra)
Seepweed, Rush (Suaeda moquinii)
Self-heal (Prunella vulgaris var. lanceolata)
Senecio, Bush (Senecio flaccidus var. douglasii)
Senna,
Bladder (Colutea
arborescens)*
Coues' (Senna covesii)
Desert (Senna
armata)
Sequoia, Giant (Sequoiadendron giganteum)*
Serviceberry, Utah (Amelanchier
utahensis)
Shadscale saltbush (Atriplex confertifolia)
Shaggy hawkweed (Hieracium horridum)
Shaggy-haired alumroot (Heuchera
hirsutissima)
Sharp-bracted rubber rabbitbrush (Ericameria
nauseosa var. ceruminosa)
Sharpleaf cancerwort (Kickxia elatine)*
Shaw's agave (Agave shawii var. shawii)
Sheep sorrel (Rumex acetosella)*
Sheep's locoweed (Astragalus
pachypus)
Shelton's violet (Viola sheltonii)
Shepherd's purse (Capsella bursa-pastoris)*
Shining milkvetch (Astragalus lentiginosus
var. micans)
Shining willow (Salix lucida ssp. lasiandra)
Shiny lomatium (Lomatium lucidum)
Shiny peppergrass (Lepidium nitidum
var. nitidum)
Shinyleaf sandpaper plant (Petalonyx nitidus)
Shockley's goldenheads (Acamptopappus
shockleyi)
Shockley's prickleleaf (Hecastocleis
shockleyi)
Shockley's rock-cress (Boechera shockleyi)
Shooting star,
Alpine (Dodecatheon
alpinum)
[Common] (Dodecatheon
clevelandii ssp. clevelandii)
Foothill (Dodecatheon
hendersonii)
Fragrant (Dodecatheon
redolens)
Island (Dodecatheon
clevelandii ssp. insulare)
Shoregrass (Monanthochloe littoralis)
Shortawn foxtail (Alopecurus aequalis var. aequalis)
Short-bannered coastal lotus (Acmispon brevivexillus var. brevivexillus)
Short-flowered California dodder (Cuscuta
occidentalis)
Short-flowered monardella (Monardella
nana) (Formerly Monardella nana ssp. tenuiflora)
Short-fruited filaree (Erodium brachycarpum)*
Short-joint beavertail cactus (Opuntia
basilaris var. brachyclada)
Shortleaf baccharis (Baccharis brachyphylla)
Short-leaved cliff aster (Malacothrix
saxatilis var. tenuifolia)
Short-leaved squirreltail (Elymus
elymoides ssp. brevifolius)
Short-lobed broom-rape (Orobanche
parishii ssp. brachyloba)
Short-winged deerweed (Acmispon glaber
var. brevialatus)
Showy Brewer's lupine (Lupinus breweri
var. grandiflorus)
Showy cycladenia (Cycladenia humilis
var. venusta)
Showy gilia (Gilia cana ssp. bernardina)
Showy gilia (Gilia cana ssp. triceps)
Showy island snapdragon (Gambelia
speciosa)
Showy penstemon (Penstemon spectabilis
var. spectabilis)
Showy penstemon (Penstemon
spectabilis var. subviscosus)
Shrub live oak (Quercus turbinella)
Shrubby brickellbush (Brickellia
frutescens)
Shrubby interior live oak (Quercus
wislizeni var. frutescens)
Sibbaldia (Sibbaldia procumbens)
Siberian milfoil (Myriophyllum sibiricum)
Sicklegrass, Curved (Parapholis incurva)*
Sicklepod rock-cress, see Elegant rock-cress
Sierra gooseberry (Ribes roezlii var.
roezlii)
Sierra hoary coffeeberry (Frangula californica ssp. cuspidata)
Sierra lessingia (Lessingia leptoclada)
Sierra lewisia (Lewisia nevadensis)
Sierra nemophila (Nemophila spatulata)
Sierra Nevada lotus (Acmispon nevadensis
var. nevadensis)
Sierra onion (Allium campanulatum)
Sierra sanicle (Sanicula graveolens)
Sierra tansy mustard (Descurainia
californica)
Sigmoid threadplant (Nemacladus sigmoideus)
Silktassel,
Ashy (Garrya
flavescens)
Canyon (Garrya
veatchii)
Coast (Garrya
elliptica)
Fremont's (Garrya
fremontii)
Silky dalea (Dalea mollis)
Silky deerweed (Acmispon procumbens var. procumbens)
Silky lupine (Lupinus elatus)
Silky raillardella (Raillardella argentea)
Silver beach bur (Ambrosia chamissonis)
Silver bush lupine (Lupinus albifrons
var. albifrons)
Silver cholla (Cylindropuntia echinocarpa)
Silver Lake daisy (Arida arizonica)
Silver lotus (Acmispon argophyllus var. argophyllus)
Silver puffs (Uropappus
lindleyi)
Silver wormwood (Artemisia ludoviciana
ssp. incompta)
Silverback fern (Pentagramma triangularis
ssp. viscosa)
Silver-haired ivesia (Ivesia argyrocoma)
Silverleaf cinquefoil (Potentilla
anserina ssp. anserina)
Silverleaf horse-nettle (Solanum
elaeagnifolium)*
Silverweed (Potentilla anserina ssp. pacifica)
Silvery false-lupine (Thermopsis macrophylla var. argentata)
Silvery lupine (Lupinus argenteus var.
argenteus)
Singleleaf pinyon pine (Pinus monophylla)
Six-weeks fescue (Vulpia octoflora var.
hirtella)
Skeleton-plant, Thorny (Pleiacanthus
spinosus)
Skeleton weed (Chondrilla juncea)*
Skullcap,
Common (Scutellaria
tuberosa)
Grayleaf (Scutellaria
siphocampyloides)
Southern (Scutellaria
bolanderi ssp. austromontana)
Skunkbush (Rhus aromatica)
Sky lupine (Lupinus nanus)
Sky pilot, Western (Polemonium occidentale)
Sleepy catchfly (Silene antirrhina)
Slender beautiful rock-cress (Boechera xylopoda)
Slender bedstraw (Galium angustifolium
ssp. gracillimum)
Slender boerhavia (Boerhavia triquetra)
Slender buckwheat (Eriogonum gracile
var. gracile)
Slender cinquefoil (Potentilla gracilis
var. fastigiata)
Slender cottonweed (Micropus californicus
var. californicus)
Slender draba (Draba albertina)
Slender everlasting (Pseudognaphalium thermale)
Slender fescue (Vulpia octoflora var. octoflora)
Slender goldenweed (Xanthisma
gracile)
Slender hairgrass (Deschampsia elongata)
Slender lipfern (Cheilanthes feei)
Slender mariposa lily (Calochortus
clavatus var. gracilis)
Slender oats (Avena barbata)*
Slender pectocarya (Pectocarya linearis
ssp. ferocula)
Slender popcorn flower (Plagiobothrys tenellus)
Slender poreleaf (Porophyllum gracile)
Slender tarplant (Deinandra
fasciculata)
Slender threadplant (Nemacladus tenuis var. tenuis)
Slender vetch (Vicia hassei)
Slender volcanic gilia (Gilia ochroleuca
ssp. exilis)
Slender wheat grass (Elymus trachycaulus ssp. trachycaulus)
Slender wild cabbage (Caulanthus major)
Slender woodland star (Lithophragma
tenellum)
Slender woollyheads (Psilocarphus
tenellus var. tenellus)
Slenderleaf collomia (Collomia linearis)
Slender-leaved iceplant (Mesembryanthemum
nodiflorum)*
Slender-leaved sunflower (Helianthus
gracilentus)
Slender-lobed four o'clock (Mirabilis tenuiloba)
Slender-petalled mustard (Thelypodium
stenopetalum)
Slender-pod jewelflower (Caulanthus
heterophyllus)
Slim aster (Symphyotrichum subulatum
var. parviflorum)
Slim tridens (Triden muticus)
Slim vetch (Vicia ludoviciana var. ludoviciana)
Small evening primrose (Camissoniopsis
micrantha)
Small fescue (Vulpia microstachys)
Small horseweed (Erigeron bonariensis)*
Small water-plantain buttercup (Ranunculus
alismifolius var. alismellus)
Small wirelettuce (Stephanomeria exigua ssp. exigua)
Smallflower bluecurls (Trichostema
micranthum)
Smallflower cryptantha (Cryptantha micrantha)
Smallflower notchleaf phacelia (Phacelia
crenulata var. minutiflora)
Smallflower threadplant (Nemacladus
ramosissimus)
Small-flowered collinsia (Collinsia
parviflora)
Small-flowered dwarf flax (Hesperolinon
micranthum)
Small-flowered eucrypta (Eucrypta
micrantha)
Small-flowered fiddleneck (Amsinckia
menziesii)
Small-flowered groundsmoke (Gayophytum
diffusum ssp. parviflorum)
Small-flowered lotus (Acmispon micranthus)
Small-flowered meconella (Meconella
denticulata)
Small-flowered morning glory (Convolvulus
simulans)
Small-flowered nightshade (Solanum
americanum)
Small-flowered soap plant (Chlorogalum
parviflorum)
Small-flowered tamarisk (Tamarix
parviflora)*
Small-head field clover (Trifolium
microcephalum)
Small-leaved cream bush (Holodiscus
discolor var. microphyllus)
Small-leaved nama (Nama pusillum)
Small-leaved rose (Rosa minutifolia)
Small-seeded spurge (Chamaesyce polycarpa)
Smartweed,
Himalayan (Polygonum
capitatum)*
Water (Polygonum
punctatum)
Willow (Polygonum
lapathifolium)
Smilo grass (Piptatherum miliaceum)*
Smoke tree (Psorothamnus spinosus)
Smooth beggar-ticks (Bidens
laevis)
Smooth boisduvalia (Epilobium campestre)
Smooth cat's ear (Hypochaeris glabra)*
Smooth flatsedge (Cyperus laevigatus)
Smooth scouring rush (Equisetum laevigatum)
Smooth willow-herb (Epilobium glaberrimum
ssp. glaberrimum)
Smooth-fruited sedge (Carex heteroneura)
Smoothleaf yerba santa (Eriodictyon
trichocalyx var. trichocalyx)
Smooth-stemmed fagonia (Fagonia
laevis)
Snakeroot (Sanicula
arguta)
Snake's head (Malacothrix coulteri)
Snakeweed,
Broom (Gutierrezia
sarothrae)
Sticky (Gutierrezia
microcephala)
Snapdragon,
Desert twining (Antirrhinum
filipes)
Rose (Antirrhinum
multiflorum)
Showy island (Gambelia
speciosa)
Twining (Antirrhinum
kelloggii)
Violet (Antirrhinum
nuttallianum ssp. nuttallianum)
Violet twining (Maurandella
antirrhiniflora)
White (Antirrhinum
coulterianum)
Sneezeweed,
Bigelow's (Helenium
bigelovii)
[Common] (Helenium
puberulum)
Snow plant (Sarcodes
sanguinea)
Snowberry,
Creeping (Symphoricarpos
mollis)
Desert (Symphoricarpos
longiflorus)
Mountain (Symphoricarpos
rotundifolius var. parishii)
White (Symphoricarpos albus var. laevigatus)
Snowdrop bush (Styrax redivivus)
Soap plant,
[Common] (Chlorogalum
pomeridianum var. pomeridianum)
Small-flowered (Chlorogalum
parviflorum)
Soda straw (Angelica lineariloba)
Soft arnica (Arnica mollis)
Soft chess (Bromus hordeaceus)*
Soft-leaved indian paintbrush (Castilleja
mollis)
Sonoran spurge (Chamaesyce micromera)
Sourclover (Melilotus indicus)*
South African cornflag (Chasmanthe
floribunda)*
South coast morning glory (Calystegia
macrostegia ssp. intermedia)
Southern alpine buckwheat (Eriogonum
kennedyi var. alpigenum)
Southern bluecurls (Trichostema austromontanum
ssp. austromontanum)
Southern California draba (Draba
corrugata)
Southern California morning glory (Calystegia
macrostegia ssp. arida)
Southern California rock draba (Draba saxosa)
Southern cattail (Typha domingensis)
Southern Chinese houses (Collinsia
concolor)
Southern coast live oak (Quercus
agrifolia var. oxyadenia)
Southern gilia (Saltugilia australis)
Southern goldenrod (Solidago confinis)
Southern honeysuckle (Lonicera
subspicata var. denudata)
Southern island morning glory (Calystegia
macrostegia ssp. amplissima)
Southern jewelflower (Streptanthus campestris)
Southern miner's lettuce (Claytonia
perfoliata ssp. mexicana)
Southern monardella (Monardella australis ssp. australis)
Southern mountain buckwheat (Eriogonum
kennedyi var. austromontanum)
Southern mountain lupine (Lupinus
excubitus var. austromontanus)
Southern mountain misery (Chamaebatia
australis)
Southern mountain phacelia (Phacelia
austromontana)
Southern mountain phlox (Phlox
austromontana)
Southern mountain woolstar (Eriastrum
densifolium ssp. austromontanum)
Southern skullcap (Scutellaria bolanderi
ssp. austromontana)
Southern tarplant (Centromadia parryi ssp. australis)
Southern tauschia (Tauschia
arguta)
Sow-thistle,
[Common] (Sonchus
oleraceus)*
Prickly (Sonchus
asper ssp. asper)*
Spanish broom (Spartium junceum)*
Spanish clover (Acmispon americanus var. americanus)
Spanish needles,
[Common] (Palafoxia
arida var. arida)
Giant (Palafoxia
arida var. gigantea)
Sparse-flowered bog orchid (Platanthera
sparsiflora)
Spearleaf (Matelea parvifolia)
Spearleaf brickellbush (Brickellia
atractyloides var. arguta)
Spearleaf mountain dandelion (Agoseris
retrorsa)
Spearmint (Mentha spicata var. spicata)*
Speckled clarkia (Clarkia cylindrica ssp. clavicarpa)
Speckled clarkia (Clarkia
cylindrica ssp. cylindrica)
Spectacle pod (Dithyrea californica)
Speedwell,
American (Veronica
americana)
Persian (Veronica
persica)*
Purslane (Veronica
peregrina ssp. xalapensis)
Thyme-leaved (Veronica
serpyllifolia ssp. humifusa)*
Water (Veronica
anagallis-aquatica)*
Spicebush (Calycanthus occidentalis)*
Spiderling,
Coulter's (Boerhavia coulteri var. palmeri)
Fivewing (Boerhavia
triquetra var. intermedia)
Scarlet (Boerhavia coccinea)
Wright's (Boerhavia wrightii)
Spike primrose (Epilobium densiflorum)
Spike-moss,
Ashy (Selaginella
cinerascens)
Bigelow's (Selaginella
bigelovii)
Bluish (Selaginella asprella)
Desert (Selaginella
eremophila)
Hansen's (Selaginella hansenii)
Watson's (Selaginella
watsonii)
Spikerush,
Common (Eleocharis
macrostachya)
Needle (Eleocharis acicularis var. acicularis)
Sand (Eleocharis
montevidensis)
Spikeweed (Centromadia pungens)
Spineflower,
Brittle (Chorizanthe
brevicornu var. brevicornu)
Five-tooth (Chorizanthe
watsonii)
Fringed (Chorizanthe
fimbriata var. fimbriata)
Lace-fringed (Chorizanthe fimbriata var. laciniata)
Leather (Lastarriaea coriacea)
Mojave (Chorizanthe spinosa)
Pink (Chorizanthe membranacea)
Prostrate (Chorizanthe
procumbens)
Rigid (Chorizanthe
rigida)
Riverside (Chorizanthe xanti var. leucotheca)
San Fernando Valley (Chorizanthe
parryi var. fernandina)
Thurber's spineflower (Centrostegia thurberi)
Wrinkled (Chorizanthe corrugata)
Xantus' (Chorizanthe xanti var. xanti)
Spineless horsebrush (Tetradymia
canescens)
Spiny aster (Chloracantha spinosa var. spinosa)
Spiny cocklebur (Xanthium spinosum)
Spiny greasebush (Glossopetalon spinescens var. aridum)
Spiny hopsage (Grayia spinosa)
Spiny horsebrush (Tetradymia spinosa)
Spiny menodora (Menodora spinescens)
Spiny rush (Juncus acutus ssp. leopoldii)
Spinystar,
Alverson's (Coryphantha alversonii)
Desert (Coryphantha chlorantha)
Rosy (Coryphantha vivipara var. rosea)
Spiraea, Rock (Petrophyton caespitosum)
Splendid gilia (Saltugilia splendens ssp. splendens)
Splendid mariposa lily (Calochortus
splendens)
Spotted buckwheat (Eriogonum maculatum)
Spotted coralroot (Corallorhiza maculata)
Spotted downingia (Downingia bella)
Spotted knapweed (Centaurea stoebe ssp. micranthos)*
Spreading dogbane (Apocynum androsaemifolium)
Spreading fleabane (Erigeron divergens)
Spreading gilia (Ipomopsis polycladon)
Spreading larkspur (Delphinium
patens ssp. hepaticoideum)
Spreading larkspur (Delphinium patens ssp. montanum)
Spreading navarretia (Navarretia
fossalis)
Spreading phlox (Phlox diffusa)
Spreading pygmyleaf (Loeflingia squarrosa)
Spreading rush (Juncus patens)
Spreading sandwort (Arenaria lanuginosa var. saxosa)
Spring draba (Draba verna)
Spring lessingia (Lessingia tenuis)
Spring vetch (Vicia sativa)*
Spruce, Big-cone (Pseudotsuga macrocarpa)
Spurge,
Arizona (Chamaesyce
arizonica)
Beetle (Euphorbia
eriantha)
Bush (Euphorbia characias)*
Caper (Euphorbia
lathyris)*
Cliff (Euphorbia
misera)
Dune (Chamaesyce
ocellata ssp. arenicola)
Mojave (Euphorbia
schizoloba)
Parry's (Chamaesyce
parryi)
Petty (Euphorbia
peplus)*
Prostrate (Chamaesyce
prostrata)*
Red-gland (Chamaesyce
melanadenia)
Small-seeded (Chamaesyce
polycarpa)
Sonoran (Chamaesyce
micromera)
Terracina (Euphorbia
terracina)*
Thyme-leaved (Chamaesyce
serpyllifolia ssp. serpyllifolia)
Warty (Euphorbia
spathulata)
Woodland (Euphorbia
lurida)
Yuma (Chamaesyce
setiloba)
Squawbush, see Skunkbrush
Squirreltail,
California (Elymus
elymoides ssp. californicus)
Short-leaved (Elymus
elymoides ssp. brevifolius)
St. Catherine's lace (Eriogonum giganteum)
St. John's wort, Scouler's (Hypericum
formosum var. scouleri)
Stansbury phlox (Phlox stansburyi)
Star gilia (Gilia stellata)
Star lily (Zigadenus
fremontii)
Star thistle, Yellow (Centaurea solstitialis)*
Star-flowered bedstraw (Galium
stellatum)
Star-flowered false solomon's seal (Smilacina
stellatum)
Starwort,
Meadow (Stellaria
longipes ssp. longipes)
Northern (Stellaria calycantha)
Sticky (Pseudostellaria
jamesiana)
Stemless mudwort (Limosella acaulis)
Stephanomeria, Chicory-leaved (Stephanomeria
cichoriacea)
Stephens' beardtongue (Penstemon stephensii)
Stickleaf (Mentzelia micrantha)
Stickseed (Lappula redowskii var. cupulata)
Sticky cinquefoil (Drymocallis
glandulosa var. reflexa)
Sticky cinquefoil (Drymocallis
glandulosa var. viscida)
Sticky cinquefoil (Drymocallis glandulosa var. wrangelliana)
Sticky dudleya (Dudleya viscida)
Sticky fagonia (Fagonia pachyacantha)
Sticky false-gilia (Allophyllum glutinosum)
Sticky lessingia (Lessingia glandulifera
var. glandulifera)
Sticky madia (Madia
gracilis)
Sticky monkeyflower (Mimulus
aurantiacus)
Sticky phacelia (Phacelia
viscida)
Sticky ringstem (Anulocaulis annulatus)
Sticky sand spurrey (Spergularia macrotheca
ssp. macrotheca)
Sticky snakeweed (Gutierrezia microcephala)
Sticky starwort (Pseudostellaria jamesiana)
Sticky tarplant, see Graceful tarplant
Sticky-leaved rabbitbrush (Chrysothamnus
viscidiflorus ssp. viscidiflorus)
Stillingia,
Broad-leaved (Stillingia
spinulosa)
Narrow-leaved (Stillingia
linearifolia)
Stinging lupine (Lupinus
hirsutissimus)
Stinkweed, Mojave (Cleomella obtusifolia)
Stipa, Giant (Stipa coronata)
Stitchwort, Douglas's (Minuartia douglasii)
Stonecrop,
Broad-leaf (Sedum
spathulifolium)
Davidson's (Sedum
niveum)
Strawberry, Wild (Fragaria
vesca)
Stream orchid (Epipactis gigantea)
Streambank lotus (Hosackia oblongifolia
var. oblongifolia)
Streptanthella, Longbeak (Streptanthella
longirostris)
Strigose lotus (Acmispon
strigosus)
Strigose sun cup (Camissonia strigulosa)
Sturdy sedge (Carex alma)
Succulent lupine, see Arroyo lupine
Sugar bush (Rhus ovata)
Sugar pine (Pinus lambertiana)
Suksdorf's monkeyflower (Mimulus
suksdorfii)
Sulphur-flowered buckwheat (Eriogonum
umbellatum var. subaridum)
Sumac, Laurel (Malosma
laurina)
Summer clover (Trifolium longipes var. nevadense)
Summer-holly
(Comarostaphylis
diversifolia ssp. diversifolia)
(Comarostaphylis
diversifolia ssp. planifolia)
Summer lupine (Lupinus formosus var. formosus)
Summer snow linanthus (Leptosiphon floribundus ssp. floribundus)
Summer snow linanthus (Leptosiphon
floribundus ssp. glaber)
Sun cup,
Booth's intermediate (Eremothera
boothii ssp. intermedia)
[Common] (Camissoniopsis
bistorta)
Desert (Eremothera
boothii ssp. desertorum)
Hairy (Camissoniopsis
hirtella)
Heartleaf (Chylismia
cardiophylla ssp. cardiophylla)
Intermediate (Camissoniopsis
intermedia)
Kern (Camissonia kernensis)
Little wiry (Camissonia
pusilla)
Mojave (Camissonia
campestris ssp. campestris)
Narrow-leaf (Eremothera refracta)
Palmer's (Tetrapteron palmeri)
Robust (Camissoniopsis robusta)
San Bernardino (Camissoniopsis
confusa)
Strigose (Camissonia
strigulosa)
Walker's (Chylismia walkeri ssp. tortilis)
Wingfruit (Chylismiella
pterosperma)
Sunflower,
Algodones Dunes (Helianthus
niveus ssp. tephrodes)
Bush (Encelia
californica)
California (Helianthus californicus)
Canyon (Venegasia
carpesioides)
Common (Helianthus
annuus)
Desert (Geraea
canescens)
Dune (Helianthus
niveus ssp. canescens)
Nevin's woolly (Constancea
nevinii)
Slender-leaved (Helianthus
gracilentus)
Woolly (Eriophyllum
lanatum var. obovatum)
Sunray (Enceliopsis nudicaulis)
Swamp knotweed (Polygonum
amphibium var. emersum)
Swamp saltbush (Atriplex amnicola)*
Swamp sedge (Carex senta)
Sweet
acacia (Vachellia farnesiana var. farnesiana)*
Sweet alyssum (Lobularia maritima)*
Sweet fennel (Foeniculum vulgare)*
Sweet pea,
Canyon (Lathyrus
vestitus var. vestitus)
Perennial (Lathyrus
latifolius)*
Sweetbush (Bebbia juncea
var. aspera)
Sweet-cicely,
[Common] (Osmorhiza
brachypoda)
Mountain (Osmorhiza
berteroi)
Sweetclover,
Yellow (Melilotus
officinalis)
White (Melilotus
albus)*
Sword fern,
Cliff (Polystichum
imbricans ssp. curtum)
Western (Polystichum
munitum)
Sycamore, Western (Platanus racemosa)
Syntrichopappus, Fremont's (Syntrichopappus
fremontii) |
