Setaria parviflora

Knotroot bristle grass, Knotroot Bristle Grass

Family: Poaceae · Type: perennial · Native

Knotroot bristle grass is a native perennial found in northern Sierra Nevada Foothills, Great Valley, central western California, southern Desert Mountains, and southwestern California in moist, disturbed areas, roadsides, and streambanks at elevations below 1,470 meters. Flowering from May to September, this grass produces small pale greenish-white spikelets in dense clusters 3 to 8 centimeters long. Growing with robust stems 70 to 120 centimeters tall, the plant has distinctive hard, knot-like swellings at its base that create a characteristic clumped growth pattern. Its leaves are narrow, 2 to 8 millimeters wide and up to 25 centimeters long, with smooth upper surfaces and relatively short leaf sheaths. The plant's unique spikelets feature 4 to 12 bristles and measure approximately 2 to 3 millimeters in length, with delicate lower and upper glumes.

Habitat: Moist, disturbed areas, roadsides, streambanks, canal banks

Bloom period: May-Sep

Elevation: < 1470 m

Bioregions: n SNF, GV, CW (exc SCoRI), SW (exc ChI, SnJt), s DMoj (uncommon)

California counties: San Diego, Stanislaus, Ventura, Los Angeles, San Bernardino, Merced, Alameda, Kern, San Luis Obispo, Fresno, Sacramento, Orange, Santa Barbara, Butte, Riverside, Marin, Tulare, Calaveras, Sonoma, Placer, Contra Costa, Glenn, Mariposa, Monterey, Nevada, San Francisco, San Mateo, Santa Cruz, Yuba, El Dorado, Humboldt, Santa Clara, Sutter, Madera, Colusa, Mono, Yolo, Tehama, Solano, Imperial, San Joaquin, Kings

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