SNOW-ON-THE-MOUNTAIN, Euphorbia marginata Pursh. 1, entire plant; 2, flower, seed pod at left; 3, seed. Annual with milky, sticky sap. Taproot slender. Stems 1 to 3 feet (30 to 90 cm) tall, erect, branched, usually with fine hairs, at least on upper part. Leaves alternate except just below the flower clusters, where they are whorled; ovate or oblong ovate, edges smooth, bright green except for conspicuous white marginal areas. Flowers small, white, in small clusters, without true petals but with 5 white appendages on the cuplike structure in which the ovary and stamens are produced. Seed pods hairy, 3-lobed and 3-seeded, elevated above the cup on a slender stalk. Found in dry soil and waste places, sometimes grown as an ornamental. The plant is poisonous to livestock, and the milky sap causes skin irritation on many persons.