Euphorbia albomarginata
Rattlesnake sandmat, Rattlesnake Sandmat
Photo by Chez Brungraber
Family: Euphorbiaceae · Type: Herb · Native
Euphorbia albomarginata (Rattlesnake sandmat) is a native California herb in the Euphorbiaceae family, recognized by perennial mat-forming habit and leaf shape.
Rattlesnake sandmat is a California native perennial found in southern San Joaquin Valley, southwestern California, and desert regions on dry slopes at elevations below 2,300 meters. Flowering from April to November, this plant produces white petal-like appendages surrounding small cyathia flowers. Growing with prostrate stems that repeatedly fork and create a distinctive two-faced growth pattern, it spreads across the ground in low, intricate formations. Its opposite leaves are small, ranging from 3 to 8 millimeters long, with round to oblong shapes and asymmetric bases. The plant produces tiny white seeds approximately 1 to 2 millimeters long, nestled within smooth, angled fruits.
Identification and appearance
Key characters: 38 sympatric species; distinguished by perennial mat-forming habit and leaf shape
Habitat and range
Habitat: Common. Dry slopes
Elevation: < 2300 m
California counties: San Bernardino, Riverside, Kern, Los Angeles, Imperial, Orange, San Diego, Inyo, Tulare, Ventura, Tehama, Santa Barbara
Outside California: to Utah, Texas, Mexico
Bloom period
Euphorbia albomarginata blooms Apr-Nov.
How to tell it apart
vs Croton: Euphorbia bleeds milky white latex and packs its flowers into a tiny cup (cyathium) rimmed with nectar glands; Croton has watery sap, stellate or scaly hairs, and ordinary small separate male and female flowers.; vs Stillingia: Euphorbia flowers sit in a gland-bearing cyathium; Stillingia bears its flowers in a spike with a pair of glands flanking each subtending bract and has no cyathium cup.; vs Ditaxis: Euphorbia has latex and the cyathium; Ditaxis has clear sap, 5-parted petaled male and female flowers, and 2-forked (malpighiaceous) hairs.; vs Asclepias: Both ooze milky sap, but Euphorbia's minute flowers cluster in a cyathium and ripen into a 3-lobed capsule; milkweeds have showy 5-parted flowers with a crown and paired follicles of plumed seeds.; vs Polygonum: Prostrate mat spurges leak milky sap when torn and have paired stipules with opposite leaves at the nodes; knotweeds have clear sap and a papery sheath (ocrea) wrapping each node.
Frequently asked questions
Is Euphorbia albomarginata native to California?
Yes. Euphorbia albomarginata is native to California (recorded as native).
When does Euphorbia albomarginata bloom?
Euphorbia albomarginata blooms Apr-Nov.
Where in California does Euphorbia albomarginata grow?
Euphorbia albomarginata occurs in San Bernardino, Riverside, Kern, Los Angeles, Imperial, Orange, San Diego, Inyo and other counties, at elevations of < 2300 m.
What plant family does Euphorbia albomarginata belong to?
Euphorbia albomarginata is in the Euphorbiaceae family, genus Euphorbia.
What habitat does Euphorbia albomarginata grow in?
Euphorbia albomarginata grows in Common. Dry slopes.
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.