Rattlesnake sandmat: Euphorbia albomarginata, Euphorbiaceae (spurge family)
This itty bitty flowering earth-hugger spreads in small patches that make pleasing organic shapes, a little reminiscent of moss in its flatness. The name rattlesnake weed is not derived from the fact that rattlesnakes dwell in its vicinity (although I'm sure they do), but because a poultice from its crushed leaves and flowers were used to treat snake bites, often in lieu of the sucking method. And even snakes may nibble it as a preventative antivenom: "a snake before fighting a rattlesnake always eats some of this weed so as to be immune to the poison." (Temalpakh: Cahuilla Indian knowledge and usage of plants, Lowell John Bean and Katherine Siva Saubel, 1972)
Despite that the milky sap is commonly regarded as toxic to humans, the plant has traditionally been applied both internally and externally to treat a range of conditions, from bathing in an infusion of it for chicken pox, to rubbing the plant on breasts to stimulate lactation.