Oxybasis macrosperma
Largeseed goosefoot
Family: Chenopodiaceae · Type: Herb · Not Native
Oxybasis macrosperma (Largeseed goosefoot) is a non-native California herb in the Chenopodiaceae family, recognized by low elevation wetland specialist with thick, fleshy deltate leaves.
Largeseed goosefoot is a naturalized annual found in coastal and central California regions, including the North Coast, Central Coast, San Francisco Bay Area, and Southern California, in wet places and marshes at elevations below 100 meters. Flowering from July to October, this plant produces small flowers in dense, spherical clusters 3 to 5 millimeters in diameter, arranged in terminal and axillary spikes. Growing 8 to 60 centimeters tall with decumbent proximal branches and ascending distal branches, it has a spreading habit. Its leaves are thick and fleshy, 8 to 60 millimeters long, roughly deltate or diamond-shaped with serrated edges, glabrous on the upper surface and powdery underneath. The seeds are distinctive, varying from vertical to horizontal, with a reddish color and a netted seed coat.
Identification and appearance
Key characters: 17 sympatric species - low elevation wetland specialist with thick, fleshy deltate leaves
Habitat and range
Habitat: Wet places, marshes
Elevation: < 100 m
Outside California: to Washington, probably native to South America
Bloom period
Oxybasis macrosperma blooms Jul-Oct.
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 macrosperma native to California?
No. Oxybasis macrosperma is not native to California (recorded as not native).
When does Oxybasis macrosperma bloom?
Oxybasis macrosperma blooms Jul-Oct.
What plant family does Oxybasis macrosperma belong to?
Oxybasis macrosperma is in the Chenopodiaceae family, genus Oxybasis.
What habitat does Oxybasis macrosperma grow in?
Oxybasis macrosperma grows in Wet places, marshes.
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.