Jaumea carnosa Salty Susan (Statewide, Baja California)
Juglans californica Black Walnut (Statewide)
Juncus acutus Spiny Rush (Southern, Central)
Juncus dubius Mariposa Rush (Statewide)
Juncus effusus Pacific Rush (Statewide)
Juncus mexicanus Mexican Rush (Statewide)
Juncus patens Wire Grass (Statewide)
Juncus species Rush (Statewide)
Juncus xiphoides Iris-Leaved Rush
Juniperus californica California Juniper (Statewide)
Justicia californica Chuparosa (Southern)
Justicia californica 'Candelita' Candelita Chuparosa (Horticultural)
Keckiella antirrhinoides Yellow Bush Penstemon (Southern)
Keckiella cordifolia Climbing Bush Penstemon (Southern)
Keckiella ternata Summer Bush Penstemon (Southern, Baja California)
Koeleria macrantha June-grass (Statewide)
Larrea tridentata Creosote Bush (Southern)
Lasthenia californica Goldfields (Statewide)
Lavatera assurgentiflora Tree Mallow (Southern)
Lavatera venosa San Benito Island Mallow (Baja California)
Layia platyglossa Tidy Tips (Statewide, Baja California)
Lepichinia fragrans Fragrant Pitcher Sage (Southern, Channel Islands)
Lepichinia ganderi Gander's Pitcher Sage (Otay Mesa Mountains, Baja California)
Leptosyne gigantea Channel Island Coreopsis (Central, Channel Islands)
Leptosyne maritima San Diego Sea Dahlia (San Diego County, Baja California)
Lessingia filaginifolia var. californica Carmel Aster (Northern)
Lewisia 'Pink Cloud' Cliff Maids
Leymus condensatus Giant Wild Rye (Southern, Central)
Leymus condensatus 'Canyon Prince' Canyon Prince Giant Wild Rye (Horticultural)
Leymus triticoides Creeping Wild Rye (Statewide)
Lilium humboldtii Humboldt Lily (Northern, Central)
Lilium pardalinum Leopard Lily
Limonium californicum Western Marsh Rosemary (Statewide)
Linum lewisii Wild Flax
Lithocarpus densiflorus Tanbark Oak (Northern, Central)
Lobelia dunnii Dunn's Lobelia (Southern, Central, Baja California)
Lomatium lucidum Shiny Lomatium, Biscuit Root (Southern, Baja California)
Lonicera subspicata Chaparral Honeysuckle (Southern)
Lonicera hispidula Hairy Honeysuckle (Statewide)
Lotus crassifolius var. otayensis Otay Mountain Lotus (Southern)
Lotus scoparius Deer Weed (Statewide)
Lupinus albifrons Shrub Lupine (Northern?)
Lupinus bicolor Dove Lupine
Lupinus chamissonis Dune Lupine (Statewide Coast)
Lupinus excubitus Grape Soda Lupine (Southern)
Lupinus truncatus Collar Lupine (Southern, Central, Baja California)
Lycium andersonii Southern Boxthorn (Statewide?)
Lycium californicum Coastal Boxthorn (Southern)
Lyonothamnus floribundus ssp. asplenifolius Fern-leaved Catalina Ironwood (Southern)
Malacothamnus densiflorus Many-flowered Bush Mallow (Southern, Baja)
Malacothamnus fasciculatus Chaparral Mallow (Southern)
Malacothamnus palmeri 'Hanging Valley' Arroyo Seco Bush Mallow (Monterey County Selection)
Malosma laurina Laurel Sumac (Southern)
Mammillaria dioica Fishhook Cactus (Southern)
Marah macrocarpus Wild Cucumber
Melica imperfecta Coast Range Melic (Northern, Southern)
Mimulus aurantiacus Bush Monkeyflower (Southern, Central)
Mimulus aurantiacus var. puniceus Red Bush Monkeyflower (Southern, Baja California)
Mimulus cardinalis Scarlet Monkeyflower (Statewide)
Mimulus 'Eleanor' (Diplacus sp.) Eleanor Monkeyflower (Horticultural)
Mimulus guttatus Seep Monkey Flower (Statewide)
Mimulus longiflorus Sticky Monkeyflower (Southern, Channel Islands, Baja California)
Mirabilis laevis (Mirabilis californica) Wishbone Bush (Southern, Central)
Mirabilis laevis var. villosa Wishbone Bush (Statewide, Baja)
Monanthochloe littoralis Shoregrass (Southern Salt Marshes)
Monardella macrantha Red Monardella (Southern, Central, Baja California)
Monardella nana Yellow Monardella (Southern, Baja California)
Monardella odoratissima Mountain Pennyroyal (Southern)
Monardella villosa Coyote Mint (Statewide)
Monardella viminea San Diego Willowy Mint (Southern)
Muhlenbergia rigens Deergrass (Statewide)
Myrica californica Pacific Wax Myrtle (Northern, Central)