Trianthema portulacastrum
Desert horsepurslane
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Family: Aizoaceae · Type: Herb · Native
Trianthema portulacastrum (Desert horsepurslane) is a native California herb in the Aizoaceae family, recognized by Tropical genus with limited distribution in California; distinctive fruit morphology.
Desert horsepurslane is a native perennial found in the San Joaquin Valley and Desert regions in moist or seasonally dry wetlands and disturbed areas at elevations below 1,000 meters. Flowering from June to November, this plant produces small flowers with purple-tinged sepals nestled close to its stems. Growing with sprawling stems less than one meter long and marked with lines of delicate hairs, the plant develops distinctive elliptic to round leaves with tapered bases and often notched tips. Its leaves feature widened stipules that occasionally have toothed edges, with leaf blades typically matching the length of their petioles. The fruit is a small cylindrical capsule about 4 to 5 millimeters long with two prominent, erect wings on its lid, containing a single reddish-brown to black seed with distinctive ridges.
Identification and appearance
Key characters: Tropical genus with limited distribution in California; distinctive fruit morphology
Habitat and range
Habitat: Uncommon. Moist or seasonally dry wetlands, disturbed areas
Elevation: < 1000 m
California counties: San Bernardino, Kern, Riverside, San Diego, Imperial, Merced, Tulare, Fresno, Los Angeles, San Luis Obispo, Kings
Outside California: to Texas, eastern North America, South America, tropics Old World
Bloom period
Trianthema portulacastrum blooms Jun-Nov.
How to tell it apart
vs Portulaca: Two-toothed stipules at leaf base vs. purslane's tuft of hairs at leaf base.; vs Oxybasis: Thick succulent leaves vs. goosefoot's thin, often mealy leaves.; vs Polycarpon: Fleshy opposite leaves vs. Polycarpon's thin whorled leaves.; vs Tetragonia: Flowers at leaf bases vs. Tetragonia's flowers sitting atop fruit.; vs Cypselea: Stipules as two simple teeth vs. Cypselea's fringed, hair-like stipules.
Frequently asked questions
Is Trianthema portulacastrum native to California?
Yes. Trianthema portulacastrum is native to California (recorded as native).
When does Trianthema portulacastrum bloom?
Trianthema portulacastrum blooms Jun-Nov.
Where in California does Trianthema portulacastrum grow?
Trianthema portulacastrum occurs in San Bernardino, Kern, Riverside, San Diego, Imperial, Merced, Tulare, Fresno and other counties, at elevations of < 1000 m.
What plant family does Trianthema portulacastrum belong to?
Trianthema portulacastrum is in the Aizoaceae family, genus Trianthema.
What habitat does Trianthema portulacastrum grow in?
Trianthema portulacastrum grows in Uncommon. Moist or seasonally dry wetlands, 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.