| Scientific Name | Common Name | Origin, if non-native | Habitat | Blooming in |
| FERNS AND THEIR ALLIES | ||||
| BLECHNACEAE | Chain Fern family | |||
| Woodwardia fimbriata | Giant chain fern | Wet places | ||
| DRYOPTERIDACEAE | Wood Fern Family | |||
| Dryopteris arguta | Wood Fern | Open, wooded slopes | ||
| EQUISETACEAE | Horsetail Family | |||
| Equisetum arvense | Common horsetail | Moist disturbed sites | ||
| Equisetum hyemale ssp. affine | Scouring rush | Streams; moist, sandy or gravelly areas | ||
| POLYPODIACEAE | Polypody Family | |||
| Polypodium californicum | Shaded canyons, streambanks | |||
| PTERIDACEAE | Maidenhair Fern Family | |||
| Adiantum jordanii | Maidenhair fern | Shaded hillsides, moist woods | ||
| Pellaea andromedifolia | Coffee fern | Rocky or dry sites | ||
| Pellaea mucronata | Bird's-food fern | Rocky or dry sites | ||
| Pentagramma triangularis | Goldenback fern | Shaded slopes or rocky sites | ||
| CONIFERS | ||||
| PINACEAE | Pine Family | |||
| Pinus sabiniana | Gray pine | Foothill woodland, chaparral | April-May | |
| FLOWERING PLANTS | ||||
| DICOTYLEDONS | ||||
| ACERACEAE | Maple Family | |||
| Acer macrophyllum | Bigleaf maple | Along streambanks and canyon floors | April-May | |
| ANACARDIACEAE | Sumac Family | |||
| Rhus trilobata | Squaw-bush | Common in canyons and creek beds, dry slopes and thickets | March-April | |
| Toxicodendron diversilobum | Poison oak | Very abundant in low places, thickets, chaparral and woodland | April-May | |
| APIACEAE | Celery Family | |||
| Angelica californica | Angelica | Dry slopes | June | |
| Anthriscus caucalis | Bur-chervil | Native to Europe | Disturbed areas, shady places | April-June |
| Apiastrum angustifolium | Wild celery | Chaparral | March-April | |
| Conium maculatum | Poison hemlock | Moist, especially disturbed, places | April-June | |
| Coriandrum sativum | Coriander, cilantro, Chinese parsley | Native to southern Europe | Disturbed areas | May-July |
| Daucus pusillus | Rattlesnake weed | Rocky or sandy places | April-June | |
| Foeniculum vulgare | Fennel | Roadside | June-October | |
| Ligusticum apiifolium | Celery-leaved lovage | Meadows, scrub or woods | June-July | |
| Lomatium californicum | California rock parsnip | Woodland, brushy slopes | April-June | |
| Lomatium dasycarpum | Lace parsnip | Rocky chaparral, woodland | March-June | |
| Lomatium macrocarpum | Large lace parsnip | Rocky chaparral, woodland | April-June | |
| Lomatium utriculatum | Bladder parsnip | Open grassy slopes, meadows, woodland | February-May | |
| Perideridia kelloggii | Squaw root | Open grassland | July-August | |
| Sanicula bipinnata | Poison sanicle | Open grassland, pine-oak woodland | April-May | |
| Sanicula bipinnatifida | Purple sanicle | Open grassland, pine-oak woodland | March-May | |
| Sanicula crassicaulis | Gamble weed | Open slopes, woodlands | March-May | |
| Torilis arvensis | Native to Europe | Disturbed places | May-June | |
| Torilis nodosa | Hedge parsley | Native to Europe | Disturbed places | April-June |
| Yabea microcarpa | Grassy slopes, chaparral, woodland | March-June | ||
| ARISTOLOCHIACEAE | Pipevine Family | |||
| Aristolochia californica | California pipe vine | Streamsides, chaparral | January-April | |
| ASCLEPIADACEAE | Milkweed Family | |||
| Asclepias cordifolia | Purple milkweed | Rocky slopes, chaparral | May-July | |
| Asclepias fascicularis | Narrow-leaved milkweed | Dry ground | June-September | |
| ASTERACEAE | Aster or Sunflower Family | |||
| Achillea millefolium | Yarrow | Open, grassy areas | March-June | |
| Achyrachaena mollis | Blowwives | Grassy sites | April-May | |
| Agoseris grandiflora | California dandelion | Grasslands, shrubland, woodland | May-July | |
| Agoseris heterophylla | Mountain dandelion | Open, grassy slopes and flats | March-May | |
| Anthemis cotula | Mayweed | Disturbed sites | May-July | |
| Artemisia douglasiana | Mugwort | Open to shady places, often in drainages | June-October | |
| Aster radulinus | Broad-leaved aster | Dry woods | July-October | |
| Baccharis pilularis | Coyote bush | Common on hillsides and canyons | August-December | |
| Baccharis salicifolia | Mule-fat | Canyon bottoms, moist streamsides | March-July | |
| Brickellia californica | California brickellia | Diverse dry habitats | August-October | |
| Calycadenia ciliosa | Rosin weed | Open, dry meadows, hillsides | June-September | |
| Calycadenia pauciflora | Small-flowered calycadenia | Open, dry meadows, hillsides | July-September | |
| Carduus pycnocephalus | Italian thistle | Native to southern Europe | Pastures, waste areas | May-July |
| Centaurea melitensis | Tocalote | Native to Europe | Disturbed fields, open woods | April-June |
| Centaurea solstitialis | Yellow star thistle | Native to southern Europe | Pastures, disturbed grassland or woodland | May-October |
| Chaenactis glabriuscula var. heterocarpha | Open slopes, ridges | April-June | ||
| Chamomilla suaveolens | Pineapple weed | Native to NW Northern America, NE Asia | Disturbed sites, footpaths, grazed land | April-August |
| Conyza canadensis | Horseweed | Disturbed sites | September-Oct | |
| Cotula australis | Brass buttons | Native to Australia | Disturbed sites | January-May |
| Ericameria arborescens | Golden fleece | Woodland, chaparral | August-November | |
| Erigeron foliosus var. hartwegii | Narrow-leaved daisy | Grassy or brushy slopes | May-July | |
| Erigeron inornatus | California rayless daisy | Chaparral, rocky sites | June-September | |
| Eriophyllum lanatum var. achillaeoides | Woolly sunflower | Dry, often rocky sites | May-July | |
| Euthamia occidentalis | Western goldenrod | Streambanks | September-November | |
| Filago californica | California filago | Bare or grassy places, drainages | March-June | |
| Filago gallica | Narrow-leaved filago | Native to Europe | Bare or grassy places | April-June |
| Gnaphalium californicum | Green cudweed | Dry open or wooded hills | January-July | |
| Gnaphalium canescens ssp.beneolens | Fragrant everlasting | Open slopes, ridges | July-November | |
| Grindelia camporum var. camporum | Great Valley grindelia | Fields, roadsides | August-September | |
| Gutierrezia californica | San Joaquin matchweed | Grasslands, slopes, outcrops | December | |
| Helianthella californica | California helianthella, perennial little sunflower | Grasslands | April-June | |
| Helianthus californicus | California sunflower | Dry, rocky soils, streambanks | June-Aug | |
| Hemizonia congesta ssp. luzulifolia | Field tarweed | Grasslands, fallow fields | September-October | |
| Hesperevax acaulis | Sandy slopes, flats, sometimes burns | |||
| Hesperevax sparsiflora | Sandy soils; dry, open areas | March-May | ||
| Hieracium albiflorum | White hawkweed | Dry forests | June-August | |
| Hypochaeris glabra | Smooth cat's-ear | Native to Europe | Disturbed sites | May-June |
| Lactuca serriola | Prickly lettuce | Native to Europe | Disturbed open areas | September-October |
| Lagophylla ramosissima | Common hareleaf | Dry habitats | May-October | |
| Madia elegans ssp. vernalis | Common madia | Grassy sites, valleys, foothills | March-June | |
| Madia exigua | Threadstem madia | Grasslands, open woodlands | May-July | |
| Madia gracilis ssp. gracilis | Slender tarweed | Grasslands, woodlands | April-August | |
| Malacothrix floccifera | Woolly malacothrix | Open burns, chaparral | May-June | |
| Micropus californicus | Slender cottonweed | Dry or moist, bare or grassy sites | March-June | |
| Psilocarphus tenellus | Slender woollyheads | Dry slopes, generally on disturbed soil | April-June | |
| Rafinesquia californica | California chicory | Shrubby slopes, open woods, common after fires | April-July | |
| Rigiopappus leptocladus | Grassy areas or among shrubs | April-June | ||
| Senecio vulgaris | Annual groundsel | Native to Europe | Disturbed sites | Flowers in most months |
| Silybum marianum | Milk thistle | Native to southern Europe | Roadsides, pastures, waste areas | May-July |
| Soliva sessilis | Common soliva | Native to South America | Disturbed sites | March-June |
| Sonchus asper ssp. asper | Sow-thistle | Native to Europe | Slightly moist waste places | Flowers in most months |
| Sonchus tenerrimus | Slender sowthistle | Disturbed sites | ||
| Stephanomeria virgata | Twiggy wreath plant | Dry, open slopes | July-November | |
| Uropappus lindleyi | Grassy areas, woods, chaparral | April-June | ||
| Wyethia helenioides | Foothill mule-ears | Open grassland, shrubland | March-April | |
| BORAGINACEAE | Borage Family | |||
| Amsinckia menziesii var. intermedia | Fiddleneck | Open, generally disturbed sites | March-June | |
| Cryptantha flaccida | Flaccid cryptantha | Open, dry sites | April | |
| Cynoglossum grande | Large-leaved hound's tongue | Shaded or open sites, woodland or chaparral | March-June | |
| Pectocarya pusilla | Little pectocarya | Dry sites in grassland, woodland | April | |
| Plagiobothrys canescens | Valley popcorn flower | Grassland, woodlands | March-May | |
| Plagiobothrys nothofulvus | Popcorn flower | Grassland, woodlands | March-May | |
| Plagiobothrys tenellus | Small popcorn flower | Dry slopes in grassland, scrub, woodland | March-May | |
| BRASSICACEAE | Mustard Family | |||
| Arabis modesta | Modest rock cress | Steep slopes, cliffs | April-May | |
| Arabis modesta ssp. rollins | Dry steep slopes, outcrops | March-June | ||
| Athysanus pusillus | Sandweed | Grassy, open slopes, rocky outcrops | March-June | |
| Barbarea orthoceras | Damp meadows, streambanks, moist woods | May-September | ||
| Barbarea vulgaris | Winter-cress | Native to Eurasia | Disturbed sites | April-May |
| Brassica juncea | Fields, disturbed sites | April | ||
| Brassica nigra | Black mustard | Native to Europe | Fields, disturbed sites | April-June |
| Capsella bursa-pastoris | Shepherd's-purse | Native to Europe | Disturbed sites | Flowers all year |
| Cardamine californica var. integrifolia | California toothwort, milkmaids | Shaded sites, canyons, woods | February-April | |
| Cardamine oligosperma | Annual bittercress | Shady banks, creek bottoms | March-July | |
| Cardamine pennsylvanica | Pennsylvania bittercress | Shady banks, creek bottoms | May-June | |
| Cardaria draba | Hoary-cress | Native to Europe | Disturbed sites | March-June |
| Descurainia sophia | Tansy-mustard | Native to Eurasia | Disturbed sites | |
| Draba verna | Whitlow-grass | Native to Europe | Open or disturbed sites | February-May |
| Erysimum capitatum | Wallflower | Many habitats | March-July | |
| Guillenia lasiophylla | California mustard | Dry, open, sometimes disturbed sites | March-June | |
| Hirschfeldia incana | Short pod mustard | Native to Eurasia | Creek bottoms, disturbed sites | May-October |
| Lepidium strictum | Peppergrass | Native to South America | Disturbed sites | March-May |
| Sinapis arvensis | Charlock | Native to Eurasia | Disturbed sites | March-October |
| Sisymbrium altissimum | Tumble-mustard | Native to Europe | Disturbed sites, fields | May-July |
| Sisymbrium officinale | Hedge-mustard | Native to Europe | Disturbed sites | April-July |
| Thysanocarpus curvipes | Lace pod | Slopes, moist meadows | March-May | |
| Tropidocarpum gracile | Keel-pod | Grassy slopes and open areas | March-May | |
| CALYCANTHACEAE | Calycanthus Family | |||
| Calycanthus occidentalis | Spice bush | Moist canyon floors and streams | April-August | |
| CAMPANULACEAE | Bellflower Family | |||
| Githopsis specularioides | Common blue cup | Chaparral, oak woodlands | April-June | |
| Triodanis biflora | Venus looking-glass | Disturbed sites | April-June | |
| CAPRIFOLIACEAE | Honeysuckle Family | |||
| Lonicera interrupta | Chaparral honeysuckle | Dry slopes, ridges | May-July | |
| Sambucus mexicana | Blue elderberry | Streambanks | March-September | |
| Symphoricarpos mollis | Trailing snowberry | Ridges, slopes | April-June | |
| CARYOPHYLLACEAE | Pink Family | |||
| Cerastium glomeratum | Mouse-ear chickweed | Native to Europe | Dry hillsides, grasslands, chaparral, disturbed sites | February-May |
| Minuartia douglasii | Douglas' sandwort | Rocky slopes in chaparral | April-June | |
| Petrorhagia dubia | Native to Europe | Disturbed sites, woodland savanna | May | |
| Sagina apetala | Dwarf pearlwort | Sandy waste areas, streamsides | May | |
| Silene gallica | Common catchfly | Native to Europe | Fields, disturbed sites | February-June |
| Stellaria media | Common chickweed | Native to Europe | Oak woodlands, meadows, disturbed sites | March-June |
| Stellaria nitens | Shining chickweed | Streambanks, open woodlands, disturbed sites | March-June | |
| CHENOPODIACEAE | Goosefoot Family | |||
| Chenopodium californicum | Perennial goosefoot | Open sites | March-June | |
| CISTACEAE | Rock-rose Family | |||
| Helianthemum scoparium | Peak rush-rose | Rocky slopes and ridges | March-June | |
| CONVOLVULACEAE | Morning-glory Family | |||
| Calystegia occidentalis | Dry slopes, chaparral | May-June | ||
| Calystegia purpurata ssp. purpurata | Solano morning-glory, bindweed | Chaparral | May-July | |
| CORNACEAE | Dogwood Family | |||
| Cornus glabrata | Brown dogwood | Moist areas | May-July | |
| CRASSULACEAE | Stonecrop Family | |||
| Crassula connata | Sand pygmy | Open areas | February-May | |
| Crassula tillaea (1) | Mediterranean sand pygmy | Native to Europe | Open, gravelly sites | March-April |
| Dudleya cymosa | Canyon live-forever | Rocky outcrops | April-June | |
| CUCURBITACEAE | Gourd Family | |||
| Marah fabaceus var. agrestis | Common manroot, wild cucumber | Streamsides, shrubby and open areas | February-April | |
| Marah watsonii | Watson's manroot, bigroot | Shrubby sites | ||
| CUSCUTACEAE | Dodder Family | March-April | ||
| Cuscuta californica (2) | California dodder | Chaparral, grassland | May-August | |
| DATISCACEAE | Datisca Family | |||
| Datisca glomerata | Durango root | Dry stream beds | May-July | |
| ERICACEAE | Heath Family | |||
| Arbutus menziesii | Pacific madrone | Oak, pine woodlands | March-May | |
| Arctostaphylos glandulosa ssp. glandulosa | Eastwood manzanita | Slopes, ridges, chaparral | January-April | |
| Arctostaphylos manzanita | Parry manzanita | Slopes, chaparral, woodland | February-April | |
| EUPHORBIACEAE | Spurge Family | |||
| Eremocarpus setigerus | Doveweed, turkey mullein | Common in dry, open areas | May-October | |
| Euphorbia crenulata | Chinese caps, spurge | Common in dry areas | March-August | |
| Euphorbia spathulata | Spurge | Occasional in open and disturbed areas | March-June | |
| FABACEAE | Pea Family | |||
| Astragalus gambelianus | Gambel's dwarf locoweed | Open, grassy sites, shrubland | March-June | |
| Cercis occidentalis | Western redbud | Dry slopes, canyons, streamsides, chaparral | February-April | |
| Hoita macrostachya | Leather root | Streamsides, spring-moist sites | July-August | |
| Lathyrus vestitus var. vestitus | Pacific peavine | Chaparral, oak woodland | April-June | |
| Lotus crassifolius | Buck lotus | Chaparral, pine woodland, disturbed sites | May-August | |
| Lotus humistratus | Hill lotus | Grassland, oak, pine woodland | March-June | |
| Lotus micranthus | Pink-flowered lotus | Open flats, fields and slopes | March-May | |
| Lotus purshianus | Spanish lotus | Chaparral, disturbed sites | June | |
| Lotus scoparius | California broom, deerweed | Chaparral, roadsides | March-August | |
| Lotus wrangelianus | Smooth hill lotus | Chaparral, disturbed sites | March-September | |
| Lupinus albifrons | Bush lupine | Open sand or rocks | March-June | |
| Lupinus bicolor | Miniature lupine | Open or disturbed sites | March-June | |
| Lupinus microcarpus var. densiflorus | White-whorled lupine | Open, or disturbed sites | April-June | |
| Lupinus succulentus | Fleshy lupine | Open or disturbed sites | February-May | |
| Medicago polymorpha | Bur clover | Native to Europe | Disturbed sites | March-June |
| Melilotus alba | White sweet clover | Native to Eurasia | Open, disturbed sites | May-September |
| Melilotus indica | Yellow sweet clover | Native to Eurasia | Open, disturbed sites | April-October |
| Pickeringia montana | Chaparral pea | Chaparral, open woodlands | April-May | |
| Rupertia physodes | California tea | Woodlands | May-July | |
| Trifolium albopurpureum | Rancheria clover | Grasslands, chaparral, pine woodlands | March-April | |
| Trifolium ciliolatum | Tree clover | Grasslands, chaparral, disturbed sites | ||
| Trifolium gracilentum | Slender clover | Open, disturbed sites | April | |
| Trifolium hirtum | Rose clover | Native to Eurasia | Disturbed sites | March-May |
| Trifolium microcephalum | Small-headed clover | Streambanks, moist, disturbed sites | March | |
| Trifolium oliganthum | Few-flowered clover | Woody or shrubby slopes | April | |
| Trifolium willdenovii | Tomcat clover | Disturbed, spring-moist soils | March-May | |
| Vicia sativa | Common vetch | Native to Europe | Disturbed sites | April-May |
| FAGACEAE | Oak Family | |||
| Quercus berberidifolia | Scrub oak | Dry slopes, chaparral | April | |
| Quercus douglasi | Blue oak | Interior foothills, woodland | March-April | |
| Quercus lobata | Valley oak | |||
| Quercus wislizeni | Interior live oak | Interior canyons, chaparral, oak/pine woodland | March-April | |
| GARRYACEAE | Silk Tassel Family | |||
| Garrya fremontii | Silk tassel | Chaparral, foothill woodland | February-March | |
| GERANIACEAE | Geranium Family | |||
| Erodium botrys | Long-beaked filaree | Native to Europe | Dry, open or disturbed sites | March-May |
| Erodium brachycarpum | Native to southern Europe | Dry, open or disturbed sites | February-May | |
| Erodium cicutarium (3) | Red-stemmed filaree | Native to southern Europe | Open, disturbed sites, grassland, shrubland | February-May |
| Erodium moschatum | White-stemmed filaree | Native to southern Europe | Common in disturbed sites | February-May |
| Geranium molle | Annual cranesbill | Native to Europe | Open to shaded disturbed sites | May-July |
| GROSSULARIACEAE | Gooseberry Family | |||
| Ribes malvaceum | Chaparral currant | Chaparral, oak woodland | October-March | |
| Ribes victoris | Victor's gooseberry | Chaparral | ||
| HIPPOCASTANACEAE | Buckeye Family | |||
| Aesculus californica | California buckeye | Along drainages, sides of streams | May-June | |
| HYDROPHYLLACEAE | Waterleaf Family | |||
| Emmenanthe penduliflora | Whispering bells | Dry, open slopes, often after burns | May-June | |
| Eriodictyon californicum | Yerba santa | Fields, woodland, chaparral | May-July | |
| Eucrypta chrysanthemifolia | Common eucrypta | Chaparral, disturbed sites | March-June | |
| Nemophila heterophylla | Vari-leaf nemophila | Partly shaded slopes, chaparral, streambanks | March-July | |
| Nemophila pedunculata | Meadow nemophila | Grasslands, woodlands, streambanks | April-August | |
| Phacelia cicutaria | Caterpillar phacelia | Slopes, grassland, chaparral, oak/pine woodland | March-May | |
| Phacelia imbricata | Imbricate phacelia | Slopes, chaparral, woodland | March-June | |
| Phacelia tanacetifolia (1) | Tansy phacelia | Slopes, open areas | March-May | |
| HYPERICACEAE | St. John's Wort Family | |||
| Hypericum perforatum | Klamathweed | Native to Europe | Pastures, disturbed sites | |