Whitemargin Sandmat

Euphorbia albomarginata is a common ground cover plant, usually growing less than 1/2 in (13 mm) high, with individual plants covering about a square foot, often growing closely and forming mats of vegetation. The flowers of this plant are tiny and edged in white, with a purplish center. It can be found in open fields, on roadsides, or anywhere where the ground is disturbed, including ornamental gravels in suburban yards, where it is considered as a weed. The former genus name Chamaesyce comes from the Greek word "chame", meaning "on the ground", and "syce" meaning "fig". This refers to the growth pattern of being flattened in all aspects, as if a box had been placed on it, so as to be lying very close to the ground. One of the defining chaparral plants, Chamise (Adenostoma fasciculatum), derives from the same word. The flower has a circular burgundy center with a white ring around it. The epithet "albomarginata" (white-margined) refers to the "white" ringed "margin" of the flower "petals". The plant actually has no petals, but has modified leaves called "bracts", more round that the green leaves on the rest of the plant, which form a cuplike shape. The 12–30 male flowers are difficult to see, consisting only of one stamen each, and are clustered in the center of the cup. …

The plant was formerly used as a folk remedy for snakebites (as a poultice or brewed as a tea) – hence the common name "rattlesnake weed". However, this species is not proven to be medically effective in treating rattlesnake venom. Like most spurges, rattlesnake weed secretes an acrid, milky sap containing alkaloids poisonous to humans, with emetic and cathartic properties that may be misconstrued as curative. Among the Zuni people, the leaves and roots are eaten to promote lactation.