Kallstroemia californica
California caltrop
Photo by Chez Brungraber
Family: Zygophyllaceae · Type: Herb · Native
Kallstroemia californica (California caltrop) is a native California herb in the Zygophyllaceae family, recognized by . Key differences: petal color (yellow vs orange) and pedicel length relative to leaves.
California caltrop is a California native annual found in the southern desert bioregion in flat, sandy, or disturbed areas at elevations below 600 meters. Flowering from August to October, this plant produces small yellow flowers 3 to 5 millimeters long. Growing prostrate to decumbent with stems less than 70 centimeters long, it spreads across the ground with a strigose to glabrous surface. Its compound leaves have 6 to 12 leaflets with small stipules 1.5 to 5 millimeters long. The fruit is a small ovoid structure 3 to 5 millimeters wide.
Identification and appearance
Key characters: 1 sympatric species. Key differences: petal color (yellow vs orange) and pedicel length relative to leaves
Habitat and range
Habitat: Flat, sandy or disturbed areas
Elevation: < 600 m
California counties: San Bernardino, Riverside, San Diego, Imperial, El Dorado, Stanislaus, Kern
Outside California: to Texas, Mexico
Bloom period
Kallstroemia californica blooms Aug-Oct.
How to tell it apart
vs Tribulus: Kallstroemia fruits are bumpy but harmless; Tribulus fruits have 2-4 stout tire-puncturing spines.; vs Eschscholzia: Kallstroemia has compound feather-like leaves; Eschscholzia has finely dissected lacy leaves and bright orange poppy flowers.; vs Zygophyllum: Kallstroemia has 6-18 thin leaflets per leaf; Zygophyllum has only 2 thick fleshy leaflets.; vs Larrea: Kallstroemia is a sprawling annual with orange flowers; Larrea is an upright shrub with yellow flowers.; vs Fagonia: Kallstroemia has soft feather-like leaves without spines; Fagonia has three rigid spine-tipped leaflets per leaf.
Frequently asked questions
Is Kallstroemia californica native to California?
Yes. Kallstroemia californica is native to California (recorded as native).
When does Kallstroemia californica bloom?
Kallstroemia californica blooms Aug-Oct.
Where in California does Kallstroemia californica grow?
Kallstroemia californica occurs in San Bernardino, Riverside, San Diego, Imperial, El Dorado, Stanislaus, Kern, at elevations of < 600 m.
What plant family does Kallstroemia californica belong to?
Kallstroemia californica is in the Zygophyllaceae family, genus Kallstroemia.
What habitat does Kallstroemia californica grow in?
Kallstroemia californica grows in Flat, sandy or disturbed areas.
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.