Centrostegia thurberi
Red triangles
Photo by Chez Brungraber
Family: Polygonaceae · Type: Herb · Native
Centrostegia thurberi (Red triangles) is a native California herb in the Polygonaceae family, recognized by Specialized desert buckwheat with unique triangular bracts and tubular flower structures.
Red triangles is a California native annual found in southern San Joaquin Valley, eastern South Coast Ranges, Transverse Ranges, southeastern Sierra Nevada, and Desert regions in sandy or gravelly habitats at elevations of 300 to 2,400 meters. Flowering from March to July, this plant produces white to pink flowers 2 to 3 millimeters long with six two-lobed perianth segments. Growing with erect stems 3 to 20 centimeters tall that are sparsely glandular, it forms delicate upright plants. Its basal leaves are glabrous, 1 to 3.5 centimeters long and 0.3 to 0.8 centimeters wide, with distinctive triangular involucres featuring three basal awns and five toothed segments. The fruit is a small brown, obconic structure 2 to 2.5 millimeters long with a curved embryo.
Identification and appearance
Key characters: Specialized desert buckwheat with unique triangular bracts and tubular flower structures
Habitat and range
Habitat: Common. Sand or gravel
Elevation: 300-2400 m
California counties: San Bernardino, Kern, Los Angeles, Inyo, Ventura, San Luis Obispo, Tulare, Riverside, Santa Barbara, Mono, Merced, San Benito, San Diego, Imperial
Outside California: to Utah, Arizona, northwestern Mexico
Bloom period
Centrostegia thurberi blooms Mar-Jul.
How to tell it apart
vs Mucronea: Centrostegia has 3 basal spines; Mucronea has no basal spines at all.; vs Chorizanthe: Centrostegia cups are distinctly 3-angled with 3 basal + 5 rim spines; Chorizanthe varies but never this specific pattern.; vs Dodecahema: Centrostegia cups are 3-angled with 3 basal spines; Dodecahema cups are 6-angled with 6 basal spines.; vs Systenotheca: Centrostegia has 3 prominent basal spines; Systenotheca has no basal spines.; vs Aristocapsa: Centrostegia has 3 basal spines plus rim spines; Aristocapsa has only 5 rim spines with no basal spines.
Frequently asked questions
Is Centrostegia thurberi native to California?
Yes. Centrostegia thurberi is native to California (recorded as native).
When does Centrostegia thurberi bloom?
Centrostegia thurberi blooms Mar-Jul.
Where in California does Centrostegia thurberi grow?
Centrostegia thurberi occurs in San Bernardino, Kern, Los Angeles, Inyo, Ventura, San Luis Obispo, Tulare, Riverside and other counties, at elevations of 300-2400 m.
What plant family does Centrostegia thurberi belong to?
Centrostegia thurberi is in the Polygonaceae family, genus Centrostegia.
What habitat does Centrostegia thurberi grow in?
Centrostegia thurberi grows in Common. Sand or gravel.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · 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.