Euphorbia micromera
Sonoran sandmat, Sonoran Sandmat
Photo by Chez Brungraber
Family: Euphorbiaceae · Type: Herb · Native
Euphorbia micromera (Sonoran sandmat) is a native California herb in the Euphorbiaceae family, recognized by small size and stipule arrangement diagnostic.
Sonoran sandmat is a California native annual found in the Colorado Desert in sandy places at elevations below 1,000 meters. Flowering from April to June and September to December, this plant produces small, inconspicuous flowers with distinctive red or pink glands. Growing with prostrate stems that repeatedly fork and spread in a two-faced pattern, it forms low-growing mats across sandy terrain. Its opposite leaves are small, measuring 1 to 7 millimeters long, with asymmetric bases and ovate to oblong shapes. The tiny spherical fruits are less than 1.5 millimeters long, containing smooth to slightly wrinkled seeds that range from white to brown.
Identification and appearance
Key characters: 23 sympatric species; small size and stipule arrangement diagnostic
Habitat and range
Habitat: Sandy places
Elevation: < 1000 m
California counties: San Bernardino, Imperial, Riverside, Kern, Inyo, San Diego, Tuolumne
Outside California: to Utah, Texas, northern Mexico
Bloom period
Euphorbia micromera blooms Apr-Jun, Sep--Dec.
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 micromera native to California?
Yes. Euphorbia micromera is native to California (recorded as native).
When does Euphorbia micromera bloom?
Euphorbia micromera blooms Apr-Jun, Sep--Dec.
Where in California does Euphorbia micromera grow?
Euphorbia micromera occurs in San Bernardino, Imperial, Riverside, Kern, Inyo, San Diego, Tuolumne, at elevations of < 1000 m.
What plant family does Euphorbia micromera belong to?
Euphorbia micromera is in the Euphorbiaceae family, genus Euphorbia.
What habitat does Euphorbia micromera grow in?
Euphorbia micromera grows in Sandy places.
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.