Sidotheca emarginata

White-margined oxytheca

Family: Polygonaceae · Type: annual · Native

Conservation status: CNPS 1B.3

White-margined oxytheca is a rare (CNPS 1B.3) California native annual found in the eastern Peninsular Ranges, specifically in the Santa Rosa Mountains of Riverside County, growing in gravelly habitats at elevations of 1,200 to 2,500 meters. Flowering from February to August, this plant produces delicate white to pink flowers with fringed linear lobes, clustered in small groups of 3 to 6 blooms. Growing with compact stems 10 to 30 centimeters tall and spreading up to 5 centimeters wide, it forms low, intricate clusters. Its leaves are narrow and elongated, with blades 1.5 to 7.5 centimeters long and 0.4 to 1.5 centimeters wide, creating a delicate green backdrop for its distinctive white-margined involucre. The fruit is small, measuring 1.8 to 2 millimeters long, with white-edged bracts bearing subtle red-tinged awns.

Habitat: Gravel

Bloom period: Feb-Aug

Elevation: 1200-2500 m

Bioregions: e PR (SnJt, Santa Rosa Mtns, Riverside Co.).

California counties: Riverside

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