Callitriche marginata

California water starwort

Family: Plantaginaceae · Type: perennial · Native

California water starwort is a California native perennial found in the California Floristic Province in shallow water environments, becoming stranded in vernal pools at elevations up to 1,500 meters. Flowering from March to June, this delicate aquatic plant produces tiny white flowers in small clusters along its slender stems. Growing with fine, thin branches that spread across water surfaces, it forms dense, low-growing mats just above or at water level. Its leaves are distinctively oblong to spoon-shaped, measuring 4 to 7 millimeters long and less than 1.5 millimeters wide, creating a delicate green network across wet habitats. The small fruits are black when mature, measuring approximately 1 millimeter wide, with an extremely narrow wing barely visible at the fruit's edges.

Habitat: Becoming stranded (often in vernal pools)

Bloom period: Mar-Jun

Elevation: < +- 1500 m

Bioregions: CA-FP

California counties: Stanislaus, Riverside, Monterey, Solano, San Luis Obispo, Kern, Shasta, Calaveras, San Diego, Orange, Mendocino, Sutter, Los Angeles, Tulare, Ventura, Santa Cruz, Colusa, San Bernardino, Sacramento, Santa Barbara, Yolo, Sonoma, Marin, Merced, Butte, Tehama, Placer, Glenn, Yuba, Contra Costa, Napa, Alameda, Humboldt, Santa Clara, San Mateo, Fresno, San Joaquin, Madera, Sierra, Lake, Tuolumne

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.