Abies concolor (White fir)
Abronia
    maritima (Red sand verbena)
    nana var. covillei (Coville's dwarf abronia)
    turbinata (White sand verbena)
    umbellata var. umbellata (Pink sand verbena)
    villosa var. aurita (Desert sand verbena)
    villosa var. villosa (Desert sand verbena)
Abutilon palmeri (Indian-mallow)
Acacia
    baileyana (Cootamundra wattle)*
    farnesiana var. farnesiana, see Vachellia farnesiana var. farnesiana
    greggii, see Senegalia greggii
    longifolia (Golden wattle)*
Acalypha californica (California copperleaf)
Acamptopappus
    shockleyi (Shockley's goldenheads)
    sphaerocephalus var. sphaerocephalus (Goldenheads)
Acanthomintha
    ilicifolia (San Diego thornmint)
    obovata ssp. cordata (Heartleaf thornmint)
Acanthoscyphus
    parishii var. cienegensis (Cienega seca oxytheca)
    parishii var. goodmaniana (Cushenbury oxytheca)
    parishii var. parishii (Parish's oxytheca)
Acer
    glabrum var. diffusum (Mountain maple)
    macrophyllum (Big-leaf maple)
    negundo (Box elder)
Achillea millefolium (Yarrow)
Achnatherum
    aridum. see Stipa arida
    coronatum, see Stipa coronata
    diegoense, see Stipa diegoensis
    hymenoides, see Stipa hymenoides
    occidentale var. occidentale, see Stipa occidentalis var. occidentalis
    parishii, see Stipa parishii var. parishii
    speciosum, see Stipa speciosa
Achyrachaena mollis (Blow wives)
Achyronychia cooperi (Frostmat)
Acmispon
    americanus var. americanus (Spanish clover)
    argophyllus var. adsurgens (San Clemente Island bird's-foot trefoil)
    argophyllus var. argophyllus (Silver lotus)
    argophyllus var. niveus (Santa Cruz Island bird's-foot trefoil)
    argyraeus var. argyraeus (Canyon bird's-foot trefoil)
    argyraeus var. multicaulis (Scrub lotus)
    brachycarpus (Hill lotus)
    dendroideus var. dendroideus (Island deerweed)
    dendroideus var. veatchii (San Miguel Island deerweed)
    denticulatus (River bar bird's-foot trefoil)
    glaber var. brevialatus (Short-winged deerweed)
    glaber var. glaber (Common deerweed)
    grandiflorus var. grandiflorus (Large-flowered lotus)
    haydonii (Pygmy lotus)
    heermannii var. heermannii (Heermann's lotus)
    maritimus var. brevivexillus (Short-bannered coastal lotus)
    maritimus var. maritimus (Coastal lotus)
    micranthus (Small-flowered lotus)
    nevadensis var. davidsonii (Davidson's lotus)
    nevadensis var. nevadensis (Sierra Nevada lotus)
    procumbens var. procumbens (Silky deerweed)
    rigidus (Desert rock pea)
    strigosus (Strigose lotus)
    wrangelianus (California lotus)
Acourtia microcephala (Perezia)
Acroptilon repens (Russian knapweed)*
Actaea rubra (Red baneberry)
Adenophyllum
    cooperi (Cooper's dyssodia)
    porophylloides (San Felipe dyssodia)
Adenostoma
    fasciculatum (Chamise)
    sparsifolium (Red shanks)
Adiantum
    aleuticum (Five-finger maidenhair fern)
    capillus-veneris (Maidenhair fern)
    jordanii (California maidenhair fern)
Adolphia californica (California adolphia)
Aegilops cylindrica (Jointed goatgrass)*
Aesculus
    californica (California buckeye)
    californica seed (California buckeye)
Agastache urticifolia (Giant hyssop)
Agave
    americana (Century plant)*
    deserti (Desert agave)
    shawii var. shawii (Shaw's agave)
    utahensis (Utah agave)
Ageratina
    adenophora (Thoroughwort)*
    herbacea (Fragrant snakeroot)
Agoseris
    grandiflora var. grandiflora (Mountain dandelion)
    heterophylla var. heterophylla (Annual mountain dandelion)
    retrorsa (Spearleaf mountain dandelion)
Agropyron
    cristatum ssp. pectinatum (Desert crested wheat grass)*
    desertorum, see cristatum ssp. pectinatum
Agrostis
    idahoensis (Idaho bentgrass)
    pallens (Seashore bentgrass)
    viridis, see Polypogon viridis
Ailanthus altissima (Tree of heaven)*
Albizia lophantha (Plume acacia)*
Aliciella
    hutchinsifolia (Desert pale gilia)
    latifolia ssp. latifolia (Broad-leaf gilia)
    leptomeria (Great Basin gilia)
    triodon (Sand gilia)
Alisma plantago-aquatica, see Alisma triviale
Alisma triviale (Water plantain)
Allenrolfea occidentalis (Iodine bush)
Allionia
    incarnata var. incarnata (Trailing windmills)
    incarnata var. villosa (Trailing windmills)
Allium
    amplectens (Narrow-leaved onion)
    atrorubens var. cristatum (Crested onion)
    burlewii (Burlew's onion)
    campanulatum (Sierra onion)
    fimbriatum var. fimbriatum (Fringed onion)
    haematochiton (Red-skinned onion)
    howellii var. clokeyi (Mt. Pinos onion)
    lacunosum var. davisiae (Davis's pitted onion)
    monticola (San Bernardino mountain onion)
    parryi (Parry's fringed onion)
    peninsulare var. peninsulare (Peninsular onion)
    praecox (Early onion)
Allophyllum
    divaricatum (Purple false-gilia)
    gilioides ssp. gilioides (Dense false-gilia)
    gilioides ssp. violaceum (Violet false-gilia)
    glutinosum (Sticky false-gilia)
    integrifolium (White false-gilia)
Alnus rhombifolia (White alder)
Alopecurus aequalis var. aequalis (Shortawn foxtail)
Aloysia wrightii (Vera dulce)
Amaranthus
    albus (Pigweed amaranth)*
    blitoides (Prostrate amaranth)
    californicus (California amaranth)
    fimbriatus (Fringed amaranth)
    torreyi (Torrey's amaranth)
Amauriopsis dissecta (Ragged-leaf bahia)
Amblyopappus pusillus (Coastweed)
Ambrosia
    acanthicarpa (Annual bur-sage)
    chamissonis (Silver beach bur)
    chenopodiifolia (Goosefoot bur-sage)
    dumosa (Burrobush)
    eriocentra (Woolly bur-sage)
    ilicifolia (Holly-leaved burbush)
    psilostachya (Western ragweed)
    pumila (San Diego ambrosia)
    salsola var. salsola (Cheesebush)
Amelanchier utahensis (Utah serviceberry)
Ammannia coccinea (Red ammannia)
Amorpha
    californica var. californica (California false-indigo)
    fruticosa (Western false-indigo)
Amphipappus fremontii var. fremontii (Chaffbush)
Amsinckia
    intermedia (Common fiddleneck)
    menziesii (Small-flowered fiddleneck)
    menziesii var. intermedia, see Amsinckia intermedia
    menziesii var. menziesii, see Amsinckia menziesii
    spectabilis var. spectabilis (Seaside fiddleneck)
    tessellata var. tessellata (Checker fiddleneck)
Amsonia tomentosa (Woolly amsonia)
Anagallis
    arvensis (Scarlet pimpernel)*
    minima (Common chaffweed)
Anemopsis californica (Yerba mansa)
Angelica
    lineariloba (Soda straw)
    tomentosa (Woolly angelica)
Anisocoma acaulis (Scalebud)
Antennaria
    dimorpha (Low pussytoes)
    media (Alpine pussytoes)
    rosea ssp. confinis (Rosy pussytoes)
Anthemis
    arvensis (Corn chamomile)*
    cotula (Mayweed)*
Anthriscus caucalis (Bur-chervil)*
Antirrhinum
    coulterianum (White snapdragon)
    filipes (Desert twining snapdragon)
    kelloggii (Twining snapdragon)
    multiflorum (Rose snapdragon)
    nuttallianum ssp. nuttallianum (Violet snapdragon)
Anulocaulis annulatus (Sticky ringstem)
Aphanes occidentalis (Western lady's mantle)
Apiastrum angustifolium (Wild celery)
Apium graveolens (Celery)*
Apocynum
    androsaemifolium (Spreading dogbane)
    cannabinum (Indian hemp)
Aptenia cordifolia (Baby sun rose)*
Aquilegia formosa (Columbine)
Arabidopsis thaliana (Mouse-ear cress)*
Arabis
    glabra, see Turritis glabra
    holboelii var. pinetorum, see Boechera pinetorum
    parishii, see Boechera parishii
    perennans, see Boechera perennans
    platysperma var. platysperma, see Boechera platysperma
    pulchra var. gracilis, see Boechera xylopoda
    pulchra var. pulchra, see Boechera pulchra
    rectissima, see Boechera rectissima
    repanda, see Boechera repanda
    shockleyi, see Boechera shockleyi
    sparsiflora var. arcuata, see Boechera arcuata
    sparsiflora var. californica. see Boechera californica
Aralia californica (California aralia)
Arbutus
    menziesii (Pacific madrone)
    menziesii fruit (Pacific madrone)
Arceuthobium campylopodum (Western dwarf mistletoe)
Arctostaphylos
    catalinae (Santa Catalina Island manzanita)
    confertiflora (Santa Rosa Island manzanita)
    gabrielensis, see Arctostaphylos glandulosa ssp. gabrielensis
    glandulosa ssp. crassifolia (Del Mar manzanita)
    glandulosa ssp. adamsii (Adams' manzanita)
    glandulosa ssp. gabrielensis (San Gabriel manzanita)
    glandulosa ssp. glaucomollis (Eastwood manzanita)
    glandulosa ssp. mollis (Santa Monica Mountains manzanita)
    glandulosa ssp. mollis, fruit (Santa Monica Mountains manzanita)
    glandulosa ssp. zacaensis (Zaca Lake manzanita)
    glauca (Big-berry manzanita)
    insularis (Island manzanita)
    otayensis (Otay manzanita)
    parryana ssp. deserticum (Parry's manzanita)
    parryana ssp. parryana (Parry's manzanita)
    patula (Greenleaf manzanita)
    peninsularis (Peninsular manzanita)
    pringlei ssp. drupacea (Pink-bracted manzanita)
    pungens (Mexican manzanita)
    tomentosa (Woollyleaf manzanita)
Arenaria
    kingii, see Eremogone kingii
    lanuginosa var. saxosa (Spreading sandwort)
    macradenia var. macradenia, see Eremogone macradenia var. macradenia
    ursina, see Eremogone ursina
Argemone
    corymbosa (Mojave prickly poppy)
    munita (Chicalote)
Argyrochosma jonesii (Jones' cloak fern)
Arida arizonica (Silver Lake daisy)
Aristida
    adscensionis (Three-awn)
    purpurea var. nealleyi (Nealley three-awn)
Armeria maritima ssp. californica (California sea-pink)
Arnica
    chamissonis (Meadow arnica)
    mollis (Soft arnica)
Artemisia
    californica (California sagebrush)
    douglasiana (Mugwort)
    dracunculus (Wild tarragon)
    ludoviciana ssp. incompta (Mountain mugwort)
    nova (Black sagebrush)
    palmeri (Palmer's sagewort)
    rothrockii (Rothrock's sagebrush)
    spinescens (Budsage)
    tridentata ssp. parishii (Parish's sagebrush)
    tridentata ssp. tridentata (Basin sagebrush)
    tridentata ssp. vaseyana (Mountain sagebrush)
Arundo donax (Giant reed)*
Asclepias
    albicans (White-stemmed milkweed)
    californica (California milkweed)
    eriocarpa (Indian milkweed)
    erosa (Desert milkweed)
    fascicularis (Narrow-leaved milkweed)
    nyctaginifolia (Mojave milkweed)
    subulata (Rush milkweed)
    vestita (Woolly milkweed)
Asparagus asparagoides (African asparagus fern)*
Asphodelus fistulosus (Onionweed)*
Aspidotis californica (California lace fern)
Aster
    alpigenus var. andersonii, see Oreostemma alpigenus var. andersonii
    ascendens, see Symphyotrichum ascendens
    bernardinus, see Symphyotrichum defoliatum
    chilensis, see Symphyotrichum chilense
    greatae, see Symphyotrichum greatae
    lanceolatus var. hesperius, see Symphyotrichum lanceolatum var. hesperium
    occidentalis var. occidentalis, see Symphyotrichum spathulatum var. spathulatum
    subulatus var. ligulatus, see Symphyotrichum subulatum var. paviflorum
Astragalus
    albens (Cushenbury milkvetch)
    aridus (Annual desert milkvetch)
    bicristatus (Crested milkvetch)
    brauntonii (Braunton's rattleweed)
    cimae var. cimae (Cima milkvetch)
    coccineus (Scarlet milkvetch)
    crotalariae (Salton milkvetch)
    curtipes (San Luis Obispo milkvetch)
    didymocarpus var. didymocarpus (Two-seeded milkvetch)
    didymocarpus var. dispermus (Dwarf white milkvetch)
    douglasii var. douglasii (Jacumba milkvetch)
    douglasii var. parishii (Parish's jacumba milkvetch)
    filipes (Narrowpod locoweed)
    gambelianus (Gambel's dwarf milkvetch)
    gilmanii (Gilman's milkvetch)
    layneae (Layne's locoweed)
    lentiginosus var. borreganus (Borrego milkvetch)
    lentiginosus var. fremontii (Fremont's milkvetch)
    lentiginosus var. micans (Shining milkvetch)
    lentiginosus var. sierrae (Bear Valley milkvetch)
    lentiginosus var. variabilis (Varied milkvetch)
    leucolobus (Bear Valley woollypod)
    magdalenae var. peirsonii (Peirson's milkvetch)
    miguelensis (San Miguel milkvetch)
    minthorniae var. villosus (Minthorn's milkvetch)
    newberryi var. newberryi (Newberry's rattleweed)
    nutans (Providence Mountains milkvetch)
    pachypus (Sheep's locoweed)
    palmeri (Palmer's milkvetch)
    panamintensis (Panamint milkvetch)
    pomonensis (Pomona locoweed)
    purshii var. lectulus (Pursh's milkvetch)
    purshii var. tinctus (Pursh's milkvetch)
    sabulonum (Gravel milkvetch)
    serenoi var. shockleyi (Naked milkvetch)
    tidestromii (Tidestrom's milkvetch)
    tricarinatus (Triple-ribbed milkvetch)
    trichopodus var. lonchus (Coast locoweed)
    trichopodus var. phoxus (Santa Barbara milkvetch)
    whitneyi var. whitneyi (Whitney's locoweed)
Astrolepis cochisensis (Scaly cloak fern)
Athyrium filix-femina var. cyclosorum (Lady fern)
Athysanus pusillus (Dwarf athysanus)
Atrichoseris platyphylla (Gravel ghost)
Atriplex
    amnicola (Swamp saltbush)*
    californica (California saltbush)
    canescens var. canescens (Fourwing saltbush)
    canescens var. laciniata (Fourwing saltbush)
    confertifolia (Shadscale saltbush)
    covillei (Arrowscale)
    elegans var. fasciculata (Wheelscale saltbush)
    glauca (Waxy saltbush)*
    hymenelytra (Desert-holly)
    lentiformis (Quail bush)
    leucophylla (Beach saltbush)
    pacifica (Pacific saltbush)
    phyllostegia, see Atriplex covillei
    polycarpa (Cattle spinach)
    prostrata (Arrowleaf saltbush)*
    semibaccata (Australian saltbush)*
    triangularis, see Atriplex prostrata
    watsonii (Watson's saltbush)
Avena
    barbata (Slender oats)*
    fatua (Common wild oats)*
Ayenia compacta (Ayenia)
Baccharis
    brachyphylla (Shortleaf baccharis)
    douglasii, see Baccharis glutinosa
    emoryi, see Baccharis salicina
    glutinosa (Salt marsh baccharis)
    malibuensis (Malibu baccharis)
    pilularis ssp. consanguinea (Coyote brush)
    plummerae ssp. plummerae (Plummer's baccharis)
    salicifolia ssp. salicifolia (Mulefat)
    salicina (Willow baccharis)
    sarothroides (Broom baccharis)
    sergiloides (Desert baccharis)
    vanessae (Encinitas baccharis)
Bahia dissecta, see Amauriopsis dissecta
Bahiopsis
    laciniata (San Diego County goldeneye)
    parishii (Parish's goldeneye)
    reticulata (Mojave goldeneye)
Baileya
    multiradiata (Desert marigold)
    pauciradiata (Lax flower)
    pleniradiata (Woolly marigold)
Balsamorhiza deltoidea (Deltoid balsamroot)
Barbarea orthoceras (Winter cress)
Bassia hyssopifolia (Five-hook bassia)
Batis maritima (Saltwort)
Bebbia juncea var. aspera (Sweetbush)
Bellis perennis (English daisy)*
Berberis
    aquifolium var. repens (Creeping grape holly)
    fremontii (Fremont's barberry)
    nevinii (Nevin's barberry)
    pinnata ssp. pinnata (California barberry)
Bergerocactus emoryi (Golden-spined cereus)
Bernardia incana (Bernardia)
Berula erecta (Water parsnip)
Beta vulgaris ssp. maritima (Sea beet)*
Bidens
    laevis (Smooth beggar-ticks)
    pilosa (Common beggar-ticks)*
Bistorta bistortoides (Western bistort)
Bituminaria bituminosa (Pitch trefoil)*
Blennosperma nanum var. nanum (Yellow carpet)
Bloomeria
    crocea var. crocea (Golden stars)
    crocea var. montana (Golden stars)
Boechera
    arcuata (Arched elegant rock-cress)
    californica (Elegant rock-cress)
    parishii (Parish's rock-cress)
    perennans (Perennial rock-cress)
    pinetorum (Pine rock-cress)
    platysperma (Broad-seeded rock-cress)
    pulchra (Beautiful rock-cress)
    rectissima (Bristly-leaved rock-cress)
    repanda (Yosemite rock-cress)
    shockleyi (Shockley's rock-cress)
    xylopoda (Slender beautiful rock-cress)
Boerhavia
    coccinea (Scarlet spiderling)
    coulteri var. palmeri (Coulter's spiderling)
    intermedia, see Boerhavia triquetra var. intermedia
    triquetra var. intermedia (Fivewing spiderling)
    wrightii (Wright's spiderling)
Bolboschoenus maritimus ssp. paludosus (Marsh bulrush)
Boschniakia strobilacea, see Kopsiopsis strobilacea
Botrychium crenulatum (Scalloped moonwort)
Bouteloua
    aristidoides var. aristodoides (Needle grama)
    eriopoda (Black grama)
    gracilis (Blue grama)
    trifida (Red grama)
Bowlesia incana (Bowlesia)
Boykinia
    occidentalis (Coast boykinia)
    rotundifolia (Round-leaved boykinia)
Brachypodium distachyon (Purple false-brome)*
Brandegea bigelovii (Brandegea)
Brassica
    fruticulosa (Mediterranean cabbage)*
    nigra (Black mustard)*
    rapa (Field mustard)*
    tournefortii (Saharan mustard)*
Brickellia
    arguta var. arguta, see Brickellia atractyloides var. arguta
    atractyloides var. arguta (Spearleaf brickellbush)
    californica (California brickellbush)
    desertorum (Desert brickellbush)
    frutescens (Shrubby brickellbush)
    incana (Woolly brickellbush)
    longifolia var. multiflora (Gum-leaved brickellbush)
    microphylla (Little-leaved brickellbush)
    multiflora, see Brickellia longifolia var. multiflora
    nevinii (Nevin's brickellbush)
    oblongifolia var. linifolia (Narrow-leaved brickellbush)
Brodiaea
    elegans (Harvest brodiaea)
    filifolia (Thread-leaved brodiaea)
    orcuttii (Orcutt's brodiaea)
    santarosae (Santa Rosa basalt brodiaea)
    terrestris ssp. kernensis (Earth brodiaea)
Bromus
    berteroanus (Chilean chess)
    carinatus var. carinatus (California brome)
    carinatus var. maritimus, see Bromus maritimus
    diandrus (Ripgut brome)*
    hallii (Hall's brome)
    hordeaceus (Soft chess)*
    madritensis ssp. rubens (Red brome)*
    maritimus (Seaside brome)
    tectorum (Cheat grass)*
    trinii, see Bromus berteroanus
Buddleja utahensis (Panamint butterfly bush)
Bursera microphylla (Elephant tree)