Pilularia americana

American pillwort

Family: Marsileaceae · Type: perennial · Native

American pillwort is a California native perennial found in northern Coast Ranges, Cascade Range, Sierra Nevada, Central Valley, Central Coast, San Francisco Bay Area, southern Coast Ranges, southern California, Transverse Ranges, Peninsular Ranges, and Modoc Plateau in vernal pools, mud flats, and lake margins at elevations below 2,000 meters. Lacking typical flowering information, this small aquatic plant grows as a low-profile green organism with leaves typically 2 to 6 centimeters long, occasionally reaching 11 centimeters. Growing with delicate, grass-like linear leaves emerging directly from the ground, it forms compact clusters in wet seasonal environments. Its leaves are slender and uniform, emerging in dense, low-growing clumps that spread across moist substrate. In wet habitats, the plant produces small round sporangium cases approximately 2 to 3 millimeters in diameter, supported by tiny stalks 1 to 3 millimeters long.

Habitat: Vernal pools, mud flats, lake margins

Elevation: < 2000 m

Bioregions: NCoRI, CaR, SNF, n SNH, GV, CCo, SnFrB, SCoR, SCo, WTR, PR, MP

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

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