Plant: Monoecious perennial forb; stems slender, often twining; herbage with stinging hairs Leaves: leaves alternate, serrate, elliptic <3 cm Flowers: flowers borne in terminal or lateral bracteate racemes staminate flowers above, 2 to many; pistillate flowers below, 1 to 2, the sepals 6 Fruit: 3-seeded capsule.