Annual, succulent herb, monoecious. Flowers in clusters, the staminate ones at the end of the branches; perianth 3-4 lobed, almost globose, lobes unequal; stamens 3-4; pistillate flowers axillary, 2-bracteolate; bracteoles folded, or keeled, later winged, often connate up to the middle; stigmas 2. Pericarp free from the globose seeds; embryo horseshoe-shaped; radicle pointing upward. One sp., S.suckleana (Torr.) Rydb., USA, Rocky Mountains, Montana to Colorado.