 | Angels Gilia | Gilia angelensis | Polemoniaceae | Phlox | Native, Common, Annual herb, typically blooms from February to April, Oak Woodland FebruaryMarchApril |
 | Annual Coreopsis | Leptosyne bigelovii | Asteraceae | Sunflower | Endemic, Common, Annual herb, typically blooms from February to June, Oak Woodland FebruaryMarchAprilMayJune |
 | Ashy Leaved Buckwheat | Eriogonum cinereum | Polygonaceae | Buckwheat | Native, Common, Shrub woody, typically blooms from June to October, coastal scrub and chaparral JuneJulyAugustSeptemberOctober |
 | Baby Blue Eyes | Nemophila menziesii | Boraginaceae | Borage | Native, Uncommon, Annual herb, typically blooms from February to June, shady canyon slopes, meadows FebruaryMarchAprilMayJune |
 | Beach Evening Primrose | Camissoniopsis cheiranthifolia | Onagraceae | Evening Primrose | Native, Common, Perennial , typically blooms from March to July, Coastal Strand MarchAprilMayJuneJuly |
 | Bee Plant | Scrophularia californica | Scrophulariaceae | Figwort | Native, Uncommon, Perennial , typically blooms from April to July, sage, chaparral AprilMayJuneJuly |
 | Big Pod Ceanothus | Ceanothus megacarpus | Rhamnaceae | Buckthorn | Endemic, Common, Shrub or Tree , typically blooms from January to March, Chaparral JanuaryFebruaryMarch |
 | Bigberry Manzanita | Arctostaphylos glauca | Ericaceae | Heath | Native, Common, Shrub , typically blooms from December to March, woodland chapparal - northern slopes DecemberJanuaryFebruaryMarch |
 | Birds Beak | Cordylanthus rigidus | Orobanchaceae | Broomrape | Native, Common, Annual herb, typically blooms from May to August, open chaparral, coastal sage MayJuneJulyAugust |
 | Black Sage | Salvia mellifera | Lamiaceae | Mint | Native, Common, Shrub , typically blooms from April to July, Coastal Sage AprilMayJuneJuly |
 | Bladderpod | Peritome arborea | Cleomaceae | Spider Flower | Native, Common, Shrub , typically blooms from January to December, Coastal Bluffs, hillsides, oak woodlands JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
 | Blue Dicks | Dipterostemon capitatus | Themidaceae | Brodiaea | Native, Common, Perennial , typically blooms from December to May, Grasslands, Sage Scrub, open places in Chaparral DecemberJanuaryFebruaryMarch |
 | Blue Larkspur | Delphinium parryi | Ranunculaceae | Buttercup | Native, Common, Perennial , typically blooms from March to May, Grasslands, edges or open spaces of Chaparral and Oak Woodland MarchAprilMay |
 | Blue-Eyed Grass | Sisyrinchium bellum | Iridaceae | Iris | Native, Common, Perennial , typically blooms from March to June, Grasslands, Coastal Scrub or Woodlands MarchAprilMayJune |
 | Brodiaea | Brodiaea terrestris | Themidaceae | Brodiaea | Native, Uncommon, Perennial , typically blooms from May to June, clay soils, grassy meadows MayJune |
 | Bush Mallow | Malacothamnus fasciculatus | Malvaceae | Mallow | Native, Common, Shrub , typically blooms from January to December, Chaparral, Coastal Sage Scrub, disturbed soil JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
 | Bush Poppy, Tree Poppy | Dendromecon rigida | Papaveraceae | Poppy | Native, Uncommon, Perennial , typically blooms from February to June, Chaparral FebruaryMarchAprilMayJune |
 | Bush Sunflower | Encelia californica | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from December to August, Chaparral and Coastal Sage Scrub DecemberJanuaryFebruaryMarch |
 | Calabazilla | Cucurbita foetidissima | Cucurbitaceae | Gourd | Native, Common, Perennial Vine , typically blooms from June to August, Sandy soil JuneJulyAugust |
 | California Aster | Corethrogyne filaginifolia | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from May to November, chaparral, sage scrub, grasslands, oak woodlands MayJuneJulyAugustSeptemberOctoberNovember |
 | California Brickellbush | Brickellia californica | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from July to November, open chaparral, coastal sage JulyAugustSeptemberOctoberNovember |
 | California Buckwheat | Eriogonum fasciculatum | Polygonaceae | Buckwheat | Native, Common, Perennial , typically blooms from January to December, Chaparral, Coastal Sage Scrub, Desert Scrub JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
 | California Buttercup | Ranunculus californicus | Ranunculaceae | Buttercup | Endemic, Uncommon, Perennial , typically blooms from February to May, Chaparral, Oak Woodland FebruaryMarchAprilMay |
 | California Coffeeberry | Frangula californica | Rhamnaceae | Buckthorn | Native, Common, Shrub , typically blooms from May to July, Chaparral and coastal sage scrub MayJuneJuly |
 | California Dodder | Cuscuta californica | Convolvulaceae | Morning Glory | Native, Common, Annual Vine herb, typically blooms from April to October, Chaparral AprilMayJuneJulyAugustSeptemberOctober |
 | California Everlasting | Pseudognaphalium californicum | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from January to July, sage scrub JanuaryFebruaryMarchAprilMayJuneJuly |
 | California Fuchsia | Epilobium canum | Onagraceae | Evening Primrose | Native, Common, Perennial , typically blooms from June to December, dry and/or rocky areas on slopes and in sage scrub JuneJulyAugustSeptemberOctoberNovemberDecember |
 | California Goldenrod | Solidago velutina | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from July to November, coastal sage scrub, chaparral, oak woodlands JulyAugustSeptemberOctoberNovember |
 | California Goldfields | Lasthenia californica | Asteraceae | Sunflower | Endemic, Common, Annual herb, typically blooms from March to May, meadows, hillsides MarchAprilMay |
 | California Laurel | Umbellularia californica | Lauraceae | Laurel | Native, Common, Shrub or Tree , typically blooms from November to March, riparian NovemberDecemberJanuaryFebruaryMarchAprilMayJuneJulyAugust |
 | California Milkweed | Asclepias californica | Apocynaceae | Dogbane | Native, Common, Perennial , typically blooms from April to June, chaparral, open slopes AprilMayJune |
 | California Plantain | Plantago erecta | Plantaginaceae | Plantain | Native, Common , Annual herb, typically blooms from March to April, Coastal Scrub, Open Areas MarchApril |
 | California Poppy | Eschscholzia californica | Papaveraceae | Poppy | Endemic, Common, Annual herb, typically blooms from February to September, meadows, Coastal Sage Scrub, sandy Riparian areas FebruaryMarchAprilMayJuneJulyAugustSeptember |
 | California Saxifrage | Micranthes californica | Saxifragaceae | Saxifrage | Endemic, Uncommon, Perennial , typically blooms from February to April, Coastal Sage FebruaryMarchApril |
 | California Thistle | Cirsium occidentale var. californ | Asteraceae | Sunflower | Endemic, Common, Perennial , typically blooms from April to August, Chaparral, Woodlands, Coastal Sage Scrub AprilMayJuneJulyAugust |
 | California Walnut | Juglans californica | Juglandaceae | Walnut | Endemic, Common, Shrub or Tree , typically blooms from February to April, Oak Woodland FebruaryMarchApril |
 | Canchalagua | Zeltnera venusta | Gentianaceae | Gentian | Native, Uncommon, Annual herb, typically blooms from May to August, open chaparral, coastal sage MayJuneJulyAugust |
 | Canyon Dodder | Cuscuta subinclusa | Convolvulaceae | Morning Glory | Native, Common, Perennial Vine , typically blooms from March to October, Chaparral MarchAprilMayJuneJulyAugustSeptemberOctober |
 | Canyon Sunflower | Venegasia carpesioides | Asteraceae | Sunflower | Native, Common, Shrub , typically blooms from December to July, shady places in Oak Woodland, Sage Scrub and Chaparral DecemberJanuaryFebruaryMarch |
 | Castor Bean | Ricinis communis | Euphorbiaceae | Spurge | Invasive, Common, Shrub , typically blooms from January to December, Streambeds, roadsides, disturbed soil; JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
 | Ceanothus | Ceanothus Species | Rhamnaceae | Buckthorn | Native, Common, Shrub , typically blooms from November to March, Chaparral, ridges, slopes, woodland, coastal scrub NovemberDecemberJanuaryFebruaryMarchAprilMayJuneJulyAugust |
 | Chalk Live-Forever | Dudleya pulverulenta | Crassulaceae | Stonecrop | Native, Common, Perennial , typically blooms from June to August, Rocky cliffsides in chaparral and coastal sage scrub JuneJulyAugust |
 | Chamise | Adenostoma fasciculatum | Rosaceae | Rose | Native, Common, Shrub , typically blooms from February to September, dry slopes in Chaparral and Sage Scrub FebruaryMarchAprilMayJuneJulyAugustSeptember |
 | Chaparral Currant | Ribes malvaceum | Grossulariaceae | Gooseberry | Native, Common, Perennial , typically blooms from December to April, Oak Woodland DecemberJanuaryFebruaryMarch |
 | Chaparral Honeysuckle | Lonicera subspicata | Caprifoliaceae | Honeysuckle | Endemic, Common, Shrub , typically blooms from April to August, Chaparral AprilMayJuneJulyAugust |
 | Checker Bloom | Sidalcea sparsifolia | Malvaceae | Mallow | Native, Uncommon, Perennial , typically blooms from March to July, Coastal Sage MarchAprilMayJuneJuly |
 | Chia, Golden Chia | Salvia columbariae | Lamiaceae | Mint | Native, Common, Annual herb, typically blooms from March to June, Coastal Sage, Chaparral MarchAprilMayJune |
 | Chinese Houses | Colinsia heterophylla | Plantaginaceae | Plantain | Native, Uncommon, Annual herb, typically blooms from February to May, Oak Woodland FebruaryMarchAprilMay |
 | Chocolate Lily | Fritillaria biflora | Liliaceae | Lily | Endemic, Uncommon, Perennial , typically blooms from January to March, Heavy clay soil JanuaryFebruaryMarch |
 | Cliff Aster | Malacothrix saxatilis | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from January to December, coastal sage/or chaparral JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
 | Coast Cholla | Cylindropuntia prolifera | Cactaceae | Cactus | Native, Common, Shrub , typically blooms from April to June, dry slopes and grasslands at low elevations near the coast or in Sage Scrub AprilMayJune |
 | Coastal Live Oak | Quercus agrifolia | Fagaceae | Beech | Native, Common, Tree , typically blooms from February to May, open woodlands FebruaryMarchAprilMay |
 | Cobweb Thistle | Cirsium occidentale | Asteraceae | Sunflower | Native, Uncommon, Perennial , typically blooms from March to July, Coastal sage MarchAprilMayJuneJuly |
 | Coffee Fern | Pellaea andromedifolia | Pteridaceae | Brake | Native, Common, Perennial , typically blooms from January to April, Chaparral and coastal sage scrub JanuaryFebruaryMarchApril |
 | Collarless Poppy | Eschscholzia caespitosa | Papaveraceae | Poppy | Native, Common, Annual herb, typically blooms from March to July, Coastal Sage MarchAprilMayJuneJuly |
 | Common Fiddleneck | Amsinckia intermedia | Boraginaceae | Borage | Native, Common, Annual herb, typically blooms from February to May, grassy hillsides, burned areas FebruaryMarchAprilMay |
 | Common Sunflower | Helianthus annus | Asteraceae | Sunflower | Native, Common, Annual herb, typically blooms from January to December, fields, roadsides and trailsides JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
 | Common Vervain | Verbena lasiostachys | Verbenaceae | Vervain | Native, Common, Perennial , typically blooms from December to August, open areas, dry or moist DecemberJanuaryFebruaryMarch |
 | Common Yarrow | Achillea millefolium | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from March to June, Chaparral MarchAprilMayJune |
 | Cottonwood | Populus fremontii | Salicaceae | Willow | Native, Common, Tree , typically blooms from January to March, lower streambeds in riparian woodlands JanuaryFebruaryMarch |
 | Coyote Brush | Baccharis pilularis | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from May to December, Sage Scrub, Oak Woodland, Chaparral and Grassland MayJuneJulyAugustSeptemberOctoberNovemberDecember |
 | Cream Cups | Platystemon californicus | Papaveraceae | Poppy | Native, Uncommon, Annual herb, typically blooms from March to May, Open areas MarchAprilMay |
 | Creek Monkey Flower | Erythranthe guttata | Phrymaceae | Lopseed | Native, Common, Annual herb, typically blooms from March to July, creeks, damp areas MarchAprilMayJuneJuly |
 | Crimson Pitcher Sage | Salvia spathacea | Lamiaceae | Mint | Native, Common, Perennial , typically blooms from February to June, Lightly-shaded areas - Chaparral, Coastal Scrub FebruaryMarchAprilMayJune |
 | Datura | Datura species | Solanaceae | Nightshade | Native, Common, Annual herb, typically blooms from March to November, full sun by roadsides, sandy or gravelly places MarchAprilMayJuneJulyAugustSeptemberOctoberNovember |
 | Deerweed | Acmispon glaber | Fabaceae | Legume | Native, Common, Perennial , typically blooms from January to August, Chaparral JanuaryFebruaryMarchAprilMayJuneJulyAugust |
 | Douglas Nightshade | Solanum douglasii | Solanaceae | Nightshade | Native, Common, Perennial , typically blooms from February to October, Shady hillsides, canyons, coastal scrubland FebruaryMarchAprilMayJuneJulyAugustSeptemberOctober |
 | Downy Monkey Flower | Erythranthe pilosus | Phrymaceae | Lopseed | Native, Common, Annual herb, typically blooms from April to August, riparian AprilMayJuneJulyAugust |
 | Eastwood Manzanita | Arctostaphylos glandulosa | Ericaceae | Heath | Native, Common, Shrub , typically blooms from November to February, Chaparral, rocky slopes and ridges NovemberDecemberJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptember |
 | Elderberry | Sambucus nigra subsp. caerulea | Adoxaceae | Muskroot | Native, Common, Tree , typically blooms from April to August, woodlands, open areas and chaparral AprilMayJuneJulyAugust |
 | Elegant Clarkia | Clarkia unguiculata | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from April to July, Sun or shade in grasslands, woodlands, and chaparral AprilMayJuneJuly |
 | Eucrypta | Eucrypta chrysanthemifolia | Boraginaceae | Waterleaf | Native, Common, Annual herb, typically blooms from January to June, woodland, sage scrub, chaparral JanuaryFebruaryMarchAprilMayJune |
 | Farewell-to-Spring | Clarkia bottae | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from April to July, Coastal Sage, open slopes AprilMayJuneJuly |
 | Fern-Leaf Phacelia | Phacelia distans | Boraginaceae | Borage | Native, Common, Annual herb, typically blooms from March to June, dry slopes in Oak Woodland and Coastal Sage MarchAprilMayJune |
 | Fiesta Flower | Pholistoma auritum | Boraginaceae | Waterleaf | Native, Common, Annual herb, typically blooms from March to May, shady areas, common throughout most plant communities MarchAprilMay |
 | Fire Heart, Bleeding Heart | Ehrendorferia ochroleuca | Papaveraceae | Poppy | Native, Uncommon, Perennial , typically blooms from April to December, Chaparral, Oak Woodland AprilMayJuneJulyAugustSeptemberOctoberNovemberDecember |
 | Fire Poppy | Papaver californicum | Papaveraceae | Poppy | Endemic, Uncommon, Annual herb, typically blooms from April to July, Chaparral AprilMayJuneJuly |
 | Foothill Penstemon | Penstemon heterophyllus | Plantaginaceae | Plantain | Endemic, Uncommon, Perennial , typically blooms from April to July, dry hillsides in Oak Woodland and Chaparral AprilMayJuneJuly |
 | Fringed Indian Pink | Silene laciniata | Caryophyllaceae | Pink | Native, Common, Perennial , typically blooms from April to July, shaded woodlands, sage scrub, chaparral AprilMayJuneJuly |
 | Fringed Linanthus | Linanthus dianthiflorus | Polemoniaceae | Phlox | Native, Uncommon, Annual herb, typically blooms from January to March, Coastal Sage, Chaparral JanuaryFebruaryMarch |
 | Fuchsia-Flowered Gooseberry | Ribes speciosum | Grossulariaceae | Gooseberry | Native, Common, Shrub , typically blooms from January to May, shaded canyons in Sage Scrub and Chaparral JanuaryFebruaryMarchAprilMay |
 | Giant Coreopsis | Coreopsis gigantea | Asteraceae | Sunflower | Endemic, Common, Perennial , typically blooms from November to June, Coastal areas, especially where fog is common NovemberDecemberJanuaryFebruaryMarchAprilMay |
 | Globe Gilia | Gilia capitata | Polemoniaceae | Phlox | Native, Uncommon, Annual herb, typically blooms from March to June, Chaparral MarchAprilMayJune |
 | Globe Lily | Calochortus albus | Liliaceae | Lily | Native, Uncommon, Perennial , typically blooms from April to June, Oak Woodland AprilMayJune |
 | Golden Currant | Ribes aureum | Grossulariaceae | Gooseberry | Native, Common, Shrub , typically blooms from January to March, stream beds, meadows JanuaryFebruaryMarch |
 | Golden Star | Bloomeria crocea | Themidaceae | Brodiaea | Native, Common, Perennial , typically blooms from April to June, Coastal Sage, Chaparral AprilMayJune |
 | Golden Yarrow | Eriophyllum confertiflorum | Asteraceae | Sunflower | Native, Common, Shrub , typically blooms from December to July, open places, dry slopes in Chaparral and Sage Scrub, rocky places at the base of cliffs DecemberJanuaryFebruaryMarch |
 | Greenbark Ceanothus | Ceanothus spinosus | Rhamnaceae | Buckthorn | Native, Common, Shrub or Tree , typically blooms from February to April, Chaparral FebruaryMarchApril |
 | Gum Plant | Grindelia camporum | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from May to September, open chaparral, coastal sage MayJuneJulyAugustSeptember |
 | Hairy Leaved Ceanothus | Ceanothus oliganthus | Rhamnaceae | Buckthorn | Endemic, Common, Shrub or Tree , typically blooms from February to April, chaparral FebruaryMarchApril |
 | Heart Leaved Penstemon | Keckiella cordifolia | Plantaginaceae | Plantain | Native, Common, Perennial , typically blooms from March to August, Coastal Sage, Oak Woodlands MarchAprilMayJuneJulyAugust |
 | Hedge Nettle | Stachys bullata | Lamiaceae | Mint | Native, Common, Perennial , typically blooms from February to July, Chaparral, Woodlands, Sage Scrub FebruaryMarchAprilMayJuneJuly |
 | Hillside Gooseberry | Ribes californicum | Grossulariaceae | Gooseberry | Endemic, Common, Shrub , typically blooms from January to March, woodland chapparal - northern slopes JanuaryFebruaryMarch |
 | Hoary Leaved Ceanothus | Ceanothus crassifolius | Rhamnaceae | Buckthorn | Native, Common, Shrub or Tree , typically blooms from February to April, Chaparral FebruaryMarchApril |
 | Holly Leaf Red Berry | Rhamnus ilicifolia | Rhamnaceae | Buckthorn | Native, Common, Shrub , typically blooms from February to April, coastal sage and chaparral FebruaryMarchApril |
 | Holly-Leaved Cherry | Prunus ilicifolia | Rosaceae | Rose | Native, Common, Perennial Shrub , typically blooms from November to June, Chaparral, canyons, moist and/or north-facing NovemberDecemberJanuaryFebruaryMarchAprilMay |
 | Humboldt Lily | Lilium humboldtii | Liliaceae | Lily | Native, Uncommon, Perennial , typically blooms from May to July, Chaparral and Oak Woodland, near streams MayJuneJuly |
 | Indian Paintbrush | Castilleja affinis | Orobanchaceae | Broomrape | Native, Common, Perennial , typically blooms from February to May, Coastal Sage Scrub, Grassland, Chaparral FebruaryMarchAprilMay |
 | Indian Warrior | Pedicularis densiflora | Orobanchaceae | Broomrape | Native, Uncommon, Perennial , typically blooms from February to April, Chaparral FebruaryMarchApril |
 | Johnny-jump-up | Viola pedunculata | Violaceae | Violet | Native, Uncommon, Perennial , typically blooms from January to May, open grassy areas in woodlands, chaparral, sage scrub JanuaryFebruaryMarchAprilMay |
 | Large-Flowered Phacelia | Phacelia grandiflora | Boraginaceae | Borage | Native, Common, Annual herb, typically blooms from January to June, woodlands, chaparral, coastal sage scrub JanuaryFebruaryMarchAprilMayJune |
 | Leather Root | Hoita macrostachya | Fabaceae | Legume | Native, Uncommon, Perennial , typically blooms from June to September, Chaparral, wetland riparian JuneJulyAugustSeptember |
 | Lemonade Berry | Rhus integrifolia | Anacardiaceae | Sumac | Native, Common, Shrub Tree , typically blooms from December to May, Chaparral, North Side DecemberJanuaryFebruaryMarch |
 | Lupine | Lupinus Species | Fabaceae | Legume | Native, Common, Annual Perennial , typically blooms from February to June, Chaparral, ridges, slopes, canyons, coastal scrub FebruaryMarchAprilMayJune |
 | Lyons Pentachaeta | Pentachaeta lyonii | Asteraceae | Sunflower | Endemic, Rare, Annual herb, typically blooms from May to August, Coastal Sage MayJuneJulyAugust |
 | Mariposa Lily | Calochortus species | Liliaceae | Lily | Endemic, Common, Perennial , typically blooms from February to June, grasslands, slopes, chaparral FebruaryMarchAprilMayJune |
 | Matilija Poppy | Romneya coulteri | Papaveraceae | Poppy | Endemic, Uncommon, Perennial , typically blooms from April to June, Coastal Sage Scrub AprilMayJune |
 | Milkmaids | Cardamine californica | Brassicaceae | Mustard | Native, Uncommon, Perennial , typically blooms from January to March, Shady, moist hillsides or stream banks in riparian areas JanuaryFebruaryMarch |
 | Milkwort | Polygala cornuta | Polygalacea | Milkwort | Native, Uncommon, Shrub , typically blooms from May to July, Riparian, Chaparral MayJuneJuly |
 | Miners Lettuce | Claytonia perfoliata | Portulacaceae | Purslane | Native, Common, Annual herb, typically blooms from January to May, shady areas in chaparral, woodland, sage scrub JanuaryFebruaryMarchAprilMay |
 | Morning Glory | Calystegia macrostegia | Convolvulaceae | Morning Glory | Native, Common, Perennial or Vine , typically blooms from March to August, Sage Scrub, Chaparral MarchAprilMayJuneJulyAugust |
 | Mountain Mahogany | Cercocarpus betuloides | Rosaceae | Rose | Native, Common, Shrub , typically blooms from February to May, Chaparral FebruaryMarchAprilMay |
 | Mugwort | Artemisia douglasiana | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from July to November, Riparian Woodlands JulyAugustSeptemberOctoberNovember |
 | Mule Fat | Baccharis salicifolia | Asteraceae | Sunflower | Native, Common, Shrub , typically blooms from January to December, Riparian JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
 | Mustard Evening Primrose | Eulobus californicus | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from March to May, Grassland, Chaparral, Coastal Sage Scrub, often on dry slopes MarchAprilMay |
 | Narrow Leaved Milkweed | Asclepias fascicularis | Apocynaceae | Dogbane | Endemic, Common, Perennial , typically blooms from May to September, Grasslands MayJuneJulyAugustSeptember |
 | Notable Penstemon | Penstemon spectabilis | Plantaginaceae | Plantain | Native, Common, Perennial , typically blooms from April to June, Sage Chaparral AprilMayJune |
 | Owl’s Clover | Castilleja exserta | Orobanchaceae | Broomrape | Native, Common, Annual herb, typically blooms from January to June, Grasslands and Coastal Sage Scrub JanuaryFebruaryMarchAprilMayJune |
 | Parry’s Phacelia | Phacelia parryi | Boraginaceae | Borage | Native, Common, Annual herb, typically blooms from March to May, Chaparral, Coastal Sage Scrub MarchAprilMay |
 | Peak Rush Rose | Crocanthemum scoparium | Cistaceae | Rock Rose | Native, Common, Shrub , typically blooms from March to July, Chaparral and coastal sage scrub MarchAprilMayJuneJuly |
 | Peninsular Onion | Allium peninsulare | Alliaceae | Onion | Native, Uncommon, Perennial , typically blooms from April to May, Coastal Sage AprilMay |
 | Perezia, Sacapellote | Acourtia microcephala | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from May to July, Woodland and or Chaparral MayJuneJuly |
 | Pin Cushion | Chaenactis artemisiifolia | Asteraceae | Sunflower | Native, Common, Annual herb, typically blooms from March to June, coastal scrub and chaparral MarchAprilMayJune |
 | Pitcher Sage | Lepechinia fragrans | Lamiaceae | Mint | Native, Common, Shrub , typically blooms from April to July, Chaparral AprilMayJuneJuly |
 | Poison Oak | Toxicodendron diversilobum | Anacardiaceae | Sumac | Native, Common, Perennial Vine , typically blooms from February to June, oak woodland FebruaryMarchAprilMayJune |
 | Prickly Pear | Opuntia oricola | Cactaceae | Cactus | Native, Common, Perennial , typically blooms from May to August, low elevation chaparral and coastal sage scrub MayJuneJulyAugust |
 | Prickly Phlox | Linanthus californicus | Polemoniaceae | Phlox | Native, Common, Perennial , typically blooms from March to June, Chaparral MarchAprilMayJune |
 | Prickly Popcorn Flower | Cryptantha muricata | Boraginaceae | Borage | Native, Common, Annual herb, typically blooms from January to June, open areas on rocky slopes JanuaryFebruaryMarchAprilMayJune |
 | Prickly Poppy | Argemone munita | Papaveraceae | Poppy | Native, Uncommon, Perennial Annual , typically blooms from April to July, dry, sandy soil or gravel AprilMayJuneJuly |
 | Purple Nightshade | Solanum xanti | Solanaceae | Nightshade | Native, Common, Shrub , typically blooms from December to June, Sage, chapparal DecemberJanuaryFebruaryMarch |
 | Purple Sage | Salvia leucophylla | Lamiaceae | Mint | Native, Common, Shrub , typically blooms from February to August, Coastal Sage FebruaryMarchAprilMayJuneJulyAugust |
 | Rattlesnake Weed | Euphorbia albomarginata | Euphorbiaceae | Spurge | Native, Common, Perennial , typically blooms from April to November, dry slopes and fields AprilMayJuneJulyAugustSeptemberOctoberNovember |
 | Red Maids | Calandrinia menziesii | Portulacaceae | Purslane | Native, Uncommon, Annual herb, typically blooms from February to June, grassy areas and woodland edges FebruaryMarchAprilMayJune |
 | Red Shank | Adenostoma sparsifolium | Rosaceae | Rose | Native, Uncommon, Shrub or Tree , typically blooms from June to September, dry slopes in rain shadow of coastal slopes JuneJulyAugustSeptember |
 | Red Skinned Onion | Allium haematochiton | Alliaceae | Onion | Native, Common, Perennial , typically blooms from March to May, hillsides near water MarchAprilMay |
 | Red-Stem Filaree | Erodium cicutarium | Geraniaceae | Geranium | Invasive, Common, Annual herb, typically blooms from November to June, open or grassy areas in dry, disturbed and/or sand NovemberDecemberJanuaryFebruaryMarchAprilMay |
 | Rock Daisy | Perityle emoryi | Asteraceae | Sunflower | Native, Uncommon, Annual herb, typically blooms from March to October, Coastal Sage MarchAprilMayJuneJulyAugustSeptemberOctober |
 | Rose Snapdragon | Antirrhinum multiflorum | Plantaginaceae | Plantain | Endemic, Uncommon, Annual herb, typically blooms from May to July, Chaparal MayJuneJuly |
 | Royal Goldfields | Lasthenia coronaria | Asteraceae | Sunflower | Native, Uncommon, Annual herb, typically blooms from March to May, open areas, hillsides MarchAprilMay |
 | Sagebrush | Artemisia californica | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from September to December, Coastal Sage SeptemberOctoberNovemberDecember |
 | San Diego Milk-aster | Stephanomeria diegensis | Asteraceae | Sunflower | Native, Common, Annual herb, typically blooms from July to December, Chaparral, Coastal Scrub JulyAugustSeptemberOctoberNovemberDecember |
 | Sand Verbena | Abronia maritima | Nyctaginaceae | Four O'Clock | Native, Common, Perennial , typically blooms from February to October, coastal dunes FebruaryMarchAprilMayJuneJulyAugustSeptemberOctober |
 | Sawtooth Goldenbush | Hazardia squarrosa | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from June to October, Chaparral, Coastal Sage Scrub JuneJulyAugustSeptemberOctober |
 | Scale Broom | Lepidospartum squamatum | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from August to November, Chaparral, Coastal Sage Scrub AugustSeptemberOctoberNovember |
 | Scarlet Bugler | Penstemon centranthifolius | Plantaginaceae | Plantain | Native, Common, Perennial , typically blooms from February to June, Sage Chaparral Oak Woodland FebruaryMarchAprilMayJune |
 | Scarlet Larkspur | Delphinium cardinale | Ranunculaceae | Buttercup | Native, Common, Perennial , typically blooms from May to August, chaparral and sage scrub MayJuneJulyAugust |
 | Scarlet Monkey Flower | Erythranthe cardinalis | Phrymaceae | Lopseed | Native, Common, Perennial , typically blooms from May to September, wet areas along creeks, seeps MayJuneJulyAugustSeptember |
 | Scrub Oak | Quercus berberidifolia | Fagaceae | Beech | Native, Common, Shrub or Tree , typically blooms from March to May, Coastal Sage MarchAprilMay |
 | Shooting Star | Primula clevelandii | Primulaceae | Primrose | Native, Common, Perennial , typically blooms from December to March, Open grassy areas DecemberJanuaryFebruaryMarch |
 | Skull Caps | Scutellaria tuberosa | Lamiaceae | Mint | Native, Uncommon, Perennial , typically blooms from February to May, Chaparral FebruaryMarchAprilMay |
 | Slender Sunflower | Helianthus gracilentus | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from May to October, Chaparral, fields, dry slopes, roadsides MayJuneJulyAugustSeptemberOctober |
 | Slender Tarweed | Deinandra fasciculata | Asteraceae | Sunflower | Native, Common, Annual herb, typically blooms from May to August, Grasslands, Chaparral MayJuneJulyAugust |
 | Slimy Monkey Flower | Erythranthe floribunda | Phrymaceae | Lopseed | Native, Common, Annual herb, typically blooms from May to September, Riparian MayJuneJulyAugustSeptember |
 | Snowberry | Symphoricarpos mollis | Caprifoliaceae | Honeysuckle | Native, Common, Perennial , typically blooms from March to May, Chaparral MarchAprilMay |
 | Soap Plant | Chlorogalum pomeridianum | Agavaceae | Agave | Native, Common, Perennial , typically blooms from May to June, coastal sage, dry grassland MayJune |
 | Southern Tauschia | Tauschia arguta | Apiaceae | Carrot | Native, Common, Perennial , typically blooms from February to June, dry slopes in Sage Scrub, Woodlands and Chaparral FebruaryMarchAprilMayJune |
 | Speckled Clarkia | Clarkia cylindrica | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from April to July, Chaparral, slopes, coastal sage, woodlands, grassl AprilMayJuneJuly |
 | Star Lily | Toxicoscordion fremontii | Melanthiaceae | Deathcamasus | Native, Uncommon, Perennial , typically blooms from February to June, Coastal Sage FebruaryMarchAprilMayJune |
 | Stick Leaf, San Luis Blazingstar | Mentzelia micrantha | Loasaceae | Loasaceae | Native, Uncommon, Annual herb, typically blooms from March to June, Coastal Sage MarchAprilMayJune |
 | Sticky Cinquefoil | Drymocallis glandulosa | Rosaceae | Rose | Native, Uncommon, Perennial , typically blooms from April to July, Oak Woodland AprilMayJuneJuly |
 | Sticky Gilia, Stinky Gilia | Allophylum glutinosum | Polemoniaceae | Phlox | Native, Uncommon, Annual herb, typically blooms from February to August, Coastal Sage FebruaryMarchAprilMayJuneJulyAugust |
 | Sticky Monkey Flower | Diplacus longiflorus | Phrymaceae | Lopseed | Native, Common, Perennial , typically blooms from March to August, Chaparral MarchAprilMayJuneJulyAugust |
 | Sticky Phacelia | Phacelia viscida | Boraginaceae | Borage | Native, Uncommon, Annual , typically blooms from March to June, Coastal sage scrub and chaparral MarchAprilMayJune |
 | Stream Orchid | Epipactis gigantea | Orchidaceae | Orchid | Native, Uncommon, Perennial , typically blooms from April to July, Riparian AprilMayJuneJuly |
 | Sugar Bush | Rhus ovata | Anacardiaceae | Sumac | Native, Common, Shrub , typically blooms from March to June, Chaparral - South facing slopes MarchAprilMayJune |
 | Sumac | Malosma laurina | Anacardiaceae | Sumac | Native, Common, Perennial , typically blooms from June to August, Chaparral JuneJulyAugust |
 | Sycamore | Platanus racemosa | Platanaceae | Sycamore | Native, Common, Tree , typically blooms from February to April, stream beds FebruaryMarchApril |
 | Tejon Milk-Aster | Stephanomeria cichoriacea | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from July to October, Chaparral, Coastal Sage JulyAugustSeptemberOctober |
 | Telegraph Weed | Heterotheca grandiflora | Asteraceae | Sunflower | Native, Common, Annual herb, typically blooms from January to December, sand, disturbed soils JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
 | Tidy Tips | Layia platyglossa | Asteraceae | Sunflower | Native, Uncommon, Annual , typically blooms from March to June, grasslands MarchAprilMayJune |
 | Toyon | Heteromeles arbutifolia | Rosaceae | Rose | Native, Common, Shrub Tree , typically blooms from May to July, Chaparral, ridges, slopes, woodland, coastal scrub MayJuneJuly |
 | Tree Tobacco | Nicotiana glauca | Solanaceae | Nightshade | Invasive, Common, Shrub Tree , typically blooms from January to December, streambeds and disturbed soils JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
 | Turkey Mullein | Croton setiger | Euphorbiaceae | Spurge | Native, Common, Annual herb, typically blooms from April to November, Common in open, sandy disturbed places AprilMayJuneJulyAugustSeptemberOctoberNovember |
 | Turkish Rugging | Chorizanthe staticoides | Polygonaceae | Buckwheat | Native, Common, Annual herb, typically blooms from April to July, grassy slopes, dry and sandy places in Chaparral AprilMayJuneJuly |
 | Twining Snapdragon | Antirrhinum kelloggii | Plantaginaceae | Plantain | Native, Common, Annual or Vine herb, typically blooms from January to May, Coastal Sage Scrub and dry areas in the Chaparral JanuaryFebruaryMarchAprilMay |
 | Two Tone Everlasting | Pseudognaphalium biolettii | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from January to May, coastal scrub and chaparral JanuaryFebruaryMarchAprilMay |
 | Valley Oak | Quercus lobata | Fagaceae | Beech | Native, Common, Tree , typically blooms from March to May, open woodlands, riparian forests, valley savannas MarchAprilMay |
 | Variable Linanthus | Leptosiphon parviflorus | Polemoniaceae | Phlox | Native, Uncommon, Annual herb, typically blooms from March to May, Coastal Sage MarchAprilMay |
 | Vinegar Weed | Trichostema lanceolatum | Lamiaceae | Mint | Native, Common, Annual herb, typically blooms from June to November, dry, sunny fields or low hills
JuneJulyAugustSeptemberOctoberNovember |
 | Violet Snapdragon | Antirrhinum nuttallianum | Plantaginaceae | Plantain | Native, Uncommon, Annual herb, typically blooms from March to June, Grassy slopes and canyons MarchAprilMayJune |
 | Virgin's Bower | Clematis lasiantha | Ranunculaceae | Buttercup | Endemic, Common, Perennial Vine , typically blooms from January to May, Canyons and Chaparral, open places in Woodlands JanuaryFebruaryMarchAprilMay |
 | Wand Buckwheat | Eriogonum elongatum | Polygonaceae | Buckwheat | Native, Common, Perennial , typically blooms from July to November, coastal scrub and chaparral JulyAugustSeptemberOctoberNovember |
 | Western Virgins Bower | Clematis ligusticifolia | Ranunculaceae | Buttercup | Native, Common, Perennial Vine , typically blooms from June to September, riparian JuneJulyAugustSeptember |
 | Western Wallflower | Erysimum capitatum | Brassicaceae | Mustard | Native, Common, Perennial , typically blooms from January to June, Openings in Chaparral JanuaryFebruaryMarchAprilMayJune |
 | Whispering Bells | Emmenanthe penduliflora | Boraginaceae | Borage | Native, Uncommon, Annual herb, typically blooms from February to June, Chaparral, Coastal Sage FebruaryMarchAprilMayJune |
 | White Chaparral Currant | Ribes indecorum | Grossulariaceae | Gooseberry | Native, Common, Perennial , typically blooms from November to February, coastal scrub and chaparral NovemberDecemberJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptember |
 | White Hedge Nettle | Stachys albens | Lamiaceae | Mint | Endemic, Common, Perennial , typically blooms from May to September, Grassands Coastal Sage MayJuneJulyAugustSeptember |
 | White Sage | Salvia apiana | Lamiaceae | Mint | Native, Common, Shrub , typically blooms from April to July, Coastal Sage AprilMayJuneJuly |
 | White Snapdragon | Antirrhinum coulterianum | Plantaginaceae | Plantain | Native, Uncommon, Annual herb, typically blooms from April to July, Sage, Chapparal AprilMayJuneJuly |
 | Wild Cucumber | Marah macrocarpus | Cucurbitaceae | Gourd | Native, Common, Perennial Vine herb vine, typically blooms from November to April, woodlands, chaparral, coastal sage scrub NovemberDecemberJanuaryFebruaryMarchAprilMayJuneJuly |
 | Wild Heliotrope | Heliotropium curassavicum | Boraginaceae | Borage | Native, Common, Perennial , typically blooms from April to November, Moist to Dry Saline Soils AprilMayJuneJulyAugustSeptemberOctoberNovember |
 | Wild Peony | Paeonia californica | Paeoniaceae | Peony | Endemic, Common, Perennial , typically blooms from December to May, Chaparral, meadows & ridges DecemberJanuaryFebruaryMarch |
 | Wild Rose | Rosa californica | Rosaceae | Rose | Native, Common, Shrub , typically blooms from March to September, moist places in many plant communities MarchAprilMayJuneJulyAugustSeptember |
 | Wild Sweet Pea | Lathyrus vestitus | Fabaceae | Legume | Native, Common, Perennial Vine , typically blooms from March to August, Chaparral, Oak Woodlands MarchAprilMayJuneJulyAugust |
 | Wild radish | Raphanus sativus | Brassicaceae | Mustard | Invasive, Common, Annual herb, typically blooms from December to May, fields, meadows, disturbed places DecemberJanuaryFebruaryMarch |
 | Willow Herb Clarkia | Clarkia epilobioides | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from April to May, Oak Woodland AprilMay |
 | Wind Poppy | Papaver heterophyllum | Papaveraceae | Poppy | Native, Uncommon, Annual herb, typically blooms from April to May, Chaparral, grassy areas AprilMay |
 | Wine Cup Clarkia | Clarkia purpurea | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from March to June, Grassy Openings MarchAprilMayJune |
 | Wishbone Bush | Mirabilis laevis | Nyctaginaceae | Four O'Clock | Native, Common, Perennial , typically blooms from November to May, Chaparral and Coastal Sage Scrub NovemberDecemberJanuaryFebruaryMarchAprilMayJune |
 | Woodland Star | Lithopragma affine | Saxifragaceae | Saxifrage | Native, Common, Perennial , typically blooms from March to May, Grasslands, mountains MarchAprilMay |
 | Woolly Blue Curls | Trichostema lanatum | Lamiaceae | Mint | Native, Common, Perennial , typically blooms from February to June, chaparral, coastal sage scrub FebruaryMarchAprilMayJune |
 | Wooly Sapphire | Eriastrum sapphirinum | Polemoniaceae | Phlox | Native, Uncommon, Annual herb, typically blooms from April to July, Chaparral AprilMayJuneJuly |
 | Yellow Monkey Flower | Diplacus brevipes | Phrymaceae | Lopseed | Native, Common, Annual herb, typically blooms from April to July, Open Chaparral AprilMayJuneJuly |
 | Yellow_Throated_Phacelia | Phacelia brachyloba | Boraginaceae | Borage | Native, Uncommon, Annual , typically blooms from March to June, coastal sage scrub and chaparral MarchAprilMayJune |
 | Yerba Mansa | Anemopsis californica | Saururaceae | Lizard Tail | Native, Uncommon, Perennial , typically blooms from March to July, Moist soils MarchAprilMayJuneJuly |
 | Yerba Santa | Eriodichtyon crassifolium | Boraginaceae | Waterleaf | Native, Common, Shrub , typically blooms from January to June, Sandy, rocky areas in chaparral and sage scrub JanuaryFebruaryMarchAprilMayJune |
 | Yucca | Hesperoyucca whipplei | Agavaceae | Agave | Native, Common, Perennial , typically blooms from April to June, chaparral or coastal sage scrub
AprilMayJune |