Oxybasis rubra
Red pigweed, Red Pigweed
Family: Chenopodiaceae · Type: Herb · Native
Oxybasis rubra (Red pigweed) is a native California herb in the Chenopodiaceae family, recognized by distinctive 3-sepaled flowers, spherical clusters, reddish seeds.
Red pigweed is a California native annual herb found in various regions, typically growing in disturbed areas at low to moderate elevations. Flowering from summer to fall, this plant produces tiny green flowers in dense, spherical clusters about 3 millimeters wide. Growing 10 to 50 centimeters tall with an upright habit, it develops branched stems with distinctive deltate to diamond-shaped leaves that range from 15 to 90 millimeters long. Its leaves are typically entire or deeply toothed, with a tapered base and smooth surface. The plant produces small seeds that are occasionally reddish, giving it a unique characteristic in its genus.
Identification and appearance
Key characters: 28 sympatric species - distinctive 3-sepaled flowers, spherical clusters, reddish seeds
How to tell it apart
vs Chenopodiastrum: Chenopodium has mealy coating; Chenopodiastrum is smooth to slightly hairy without mealy texture.; vs Atriplex: Chenopodium has perfect flowers; Atriplex has separate male/female flowers with paired bracts on fruits.; vs Blitum: Chenopodium has dry fruits; Blitum has fleshy, berry-like fruiting calyxes.; vs Amaranthus: Chenopodium has mealy coating; Amaranthus is smooth with dense bristly flower spikes.; vs Rumex: Chenopodium has 5-parted flowers in clusters; Rumex has 6-parted flowers in whorls.
Frequently asked questions
Is Oxybasis rubra native to California?
Yes. Oxybasis rubra is native to California (recorded as native).
What plant family does Oxybasis rubra belong to?
Oxybasis rubra is in the Chenopodiaceae family, genus Oxybasis.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.