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Rattlesnake-weed Chamaesyce albomarginata


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credit: Stan Shebs/CCSA

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Alternate name: White-margin Sandmat

Family: Euphorbiaceae, Spurge view all from this family

Description Dense, thin mats of small, roundish opposite leaves and slender stems have milky sap, and have many tiny white flower-like cups.
Habit: native perennial herb; creeping, branched stems, green to poink; white milky sap.
Height: stems to 10 in (25 cm) long.
Leaf: tiny, opposite, dusty green with lighter margin, held horizontally, broadly ovate to oblong or round, with opposite stems connected; to 0.35 in (9 mm) long and almost as wide.
Flower: small flower-like structure, at most 0.5 in (12 mm) wide, with 4-5 wide oval bracts, white with brownish-red throat; on short stalk at each leaf node.

Warning Most members of this family are poisonous, and their milky sap can irritate the eyes, mouth, and mucous membranes. Sensitivity to a toxin varies with a personís age, weight, physical condition, and individual susceptibility. Children are most vulnerable because of their curiosity and small size. Toxicity can vary in a plant according to season, the plantís different parts, and its stage of growth; and plants can absorb toxic substances, such as herbicides, pesticides, and pollutants from the water, air, and soil.

Flower February to November.

Habitat Dry open areas; deserts, arid grassland, pinon and juniper woodlands, bajadas, cracks in paving, waste areas, disturbed sites.

Range Native to southwest and southeastern U.S., from southern California, east to southern Utah, southeast to Oklahoma and Louisiana, and into Mexico; introduced in Hawaii.

Discussion Also called whitemargin sandmat, matspurge. The latin name Euphorbia albomarginata is also used. One of the showiest of the low spurges, it was once thought useful for treatment of snakebite; hence its common name.

As in dogwood, the "flower petals" of C. albomarginata are really bracts. Only one of the true flowers is visible: the female flower is the green or red globe (an ovary) with several pistils, held on a stalk at the center of the "flower". This flower structure, called a cyathium, is typical of many Euphorbia.