Juncus ambiguus

Frog rush, Frog Rush

Family: Juncaceae · Type: annual · Native

Frog rush is a naturalized annual found in northern California coastal regions, Klamath Ranges, Central Valley, central and southern coastal areas, Channel Islands, and mountain regions at elevations generally below 500 meters in moist, often saline places. While flowering details are not specified, the plant has a distinctive growth pattern as a densely clustered or single-stemmed rush 3 to 17 centimeters tall with stems 0.5 to 1 millimeter wide. Growing with typically 1 to 2 cauline leaves, this small rush has delicate structural characteristics including sepals 4 to 6.8 millimeters long and petals 3.3 to 5.3 millimeters long. Its leaves are sparse and positioned near the stem, with an inflorescence where the lowest bract extends beyond the flower cluster. Small ovoid or barrel-shaped seeds approximately 0.3 to 0.4 millimeters long complete the plant's subtle botanical profile.

Habitat: Uncommon. Moist generally saline places

Elevation: generally < 500 m

Bioregions: NCo, KR, CaRF, SnJV, CCo, SnFrB, SCo, ChI, SnGb, MP (exc Wrn)

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