Chorizanthe cuspidata var. cuspidata
San francisco bay spineflower, San Francisco Bay Spineflower
(c) LJ Moore-McClelland, some rights reserved (CC BY), uploaded by LJ Moore-McClelland · licence
Family: Polygonaceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Chorizanthe cuspidata var. cuspidata (San francisco bay spineflower) is a native California herb in the Polygonaceae family, recognized by hooked awns and scarious margins vs. var. villosa.
San francisco bay spineflower is a rare (CNPS 1B.2) California native perennial found in northern California Coast and San Francisco Bay bioregions in sandy habitats at elevations below 300 meters. Flowering from April to July, this plant produces white to pink flowers with hooked awns in delicate involucre structures. Growing with decumbent to prostrate branches 10 to 25 centimeters long, it spreads low across sandy ground. Its small leaves are approximately 5 to 25 millimeters long and 3 to 7 millimeters wide, forming dense ground-hugging clusters. The fruit measures 2 to 2.5 millimeters long, contributing to its compact and intricate growth form.
Identification and appearance
Key characters: 14 sympatric species; hooked awns and scarious margins vs. var. villosa
Habitat and range
Habitat: Sand
Elevation: < 300 m
California counties: San Francisco, Sonoma, San Mateo, Marin, Alameda, Monterey
Bloom period
Chorizanthe cuspidata var. cuspidata blooms Apr-Jul.
Conservation status
CNPS 1B.2
How to tell it apart
vs Eriogonum: Chorizanthe has 1 flower per involucre; Eriogonum has multiple flowers per involucre.; vs Eremothera: Chorizanthe has 6-parted flowers in spiny cups; Eremothera has 4-petaled evening-primrose flowers.; vs Calyptridium: Chorizanthe has flowers in awned involucres; Calyptridium has naked flowers with papery sepals.; vs Lastarriaea: Chorizanthe has thin papery flowers; Lastarriaea has distinctly thick, leathery-textured flowers.; vs Navarretia: Chorizanthe is in Polygonaceae with 6-parted flowers; Navarretia is in Polemoniaceae with 5-lobed tubular flowers.
Frequently asked questions
Is Chorizanthe cuspidata var. cuspidata native to California?
Yes. Chorizanthe cuspidata var. cuspidata is native to California (recorded as native).
When does Chorizanthe cuspidata var. cuspidata bloom?
Chorizanthe cuspidata var. cuspidata blooms Apr-Jul.
Where in California does Chorizanthe cuspidata var. cuspidata grow?
Chorizanthe cuspidata var. cuspidata occurs in San Francisco, Sonoma, San Mateo, Marin, Alameda, Monterey, at elevations of < 300 m.
What plant family does Chorizanthe cuspidata var. cuspidata belong to?
Chorizanthe cuspidata var. cuspidata is in the Polygonaceae family, genus Chorizanthe.
Is Chorizanthe cuspidata var. cuspidata rare or endangered?
Chorizanthe cuspidata var. cuspidata carries California Rare Plant Rank 1B.2, state rank S1.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
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.