WILDFLOWERS OF NEW MEXICO

Tiny, white flowers dot this prostrate, mat-like plant. Rounded leaves cover the fleshy, red stems which form a dense, sprawling matrix. Desperate settlers thought the plant was a remedy for snakebite, hence the common name. The species name refers to the whitish leaf margins. Note the hairless stems and leaves, and the milky sap.  Recent sources have lumped all Chamaesyce  species as a subgenus within Euphorbia  based on DNA analysis.

FLOWERS: April-November. White cup-like structure (cyathium) with greenish-maroon center surrounds the tiny flowers. When fertilized, the central flower extends and hangs out of the cyathium with a hairless, 3-angled, bb-sized capsule.

LEAVES: Opposite with a single white scale (stipule) with a ragged edge at the base if each leaf stem (petiole). Blade round to oblong, 1/8–3/8 inch (3–8 mm) long, hairless; margin white to reddish, toothless.

HABITAT: Gravelly, sandy soils, disturbed areas; desert scrub and grasslands, pinyon-juniper woodlands.

ELEVATION: 3,600–6,700 feet.

RANGE: AZ, CA, HI (I), LA, NV, NM, OK, TX, UT.

SIMILAR SPECIES: 27 species of the Chamaesyce subgenus in NM, many with white flowers. The rounded, hairless, toothless leaves and the white and maroon flowers distinguish E. albomarginata. The look-alike Fendler’s Spurge, E. fendleri, also nearly statewide, has separate, linear white scales (stipules) at the base of each paired leaf. Thymeleaf Sandmat, E. serpyllifolia, a statewide annual, has hairless red stems and hairless, oblong leaves with scattered teeth on outer half. Prostrate Sandmat, E. prostrata, an annual scattered in the southern half of NM and occasional elsewhere, has hairy, light green to pale red stems, and hairy leaf bottoms, and capsules.

NM COUNTIES: Nearly statewide, except ne NM, in low- to mid-elevation, dry habitats: Bernalillo, Catron, Cibola, Chaves, De Baca, Dona Ana, Eddy, Grant, Guadalupe, Hidalgo, Lea, Lincoln, Luna, McKinley, Otero, Quay, Roosevelt, San Juan, Sandoval, Sierra, Socorro, Valencia.