Idahoa scapigera

Oldstem idahoa

Family: Brassicaceae · Type: annual · Native

Oldstem idahoa is a California native annual found in northern California regions including Mount Saint Helena, the Cascade Range, northern Sierra Nevada, southern Sierra Nevada foothills, Mount Hamilton, and Great Basin areas in moist ledges, slopes, and meadows at elevations of 200 to 1,700 meters. Flowering from March to May, this delicate plant produces small white flowers on slender peduncles 2 to 13 centimeters long. Growing as a scapose plant with multiple thin stems, it forms a low basal rosette of leaves. Its leaves are distinctive, ranging from 7 to 20 millimeters long, with an ovate to spoon-shaped form, creating a compact ground-hugging growth pattern. The plant produces small round to wide-ovate silicles 6 to 9 millimeters long, each containing 6 to 10 seeds.

Habitat: Moist ledges, slopes, meadows, foothills

Bloom period: Mar-May

Elevation: 200-1700 m

Bioregions: NCoRI (Mount Saint Helena), CaR, n SN, s SNF, SnFrB (Mount Hamilton), SCoRI, GB

California counties: Kern, Santa Clara, Trinity, Siskiyou, Modoc, Butte, Lassen, Plumas, Shasta, Tehama, Sierra, Lake, Calaveras, Napa, Alpine

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