STINGING NETTLE, Urtica dioica L. 1, lower part of plant; 2, upper part of plant with flowers; 3, section of stem with hairs; 4, seed. Perennial, reproducing by seeds and underground rootstocks. Stems 2 to 7 feet (0.6 to 2 m) tall, slightly branched near the top, slender, rigid, covered with numerous stinging hairs. Leaves dark green, coarse, opposite, 3 to 6 inches (7.5 to 15 cm) long, pointed with saw-toothed margins, sometimes rounded at base, covered with stinging hairs. Flowers are greenish without petals and produced in clusters in the leaf axiIs. Male and female flowers borne separately but on the same plant. Seed pod 1-seeded. Seeds small, eggshaped, slightly rough, yellow to grayish-tan. Found in barnyards, fence rows, thickets, waste places, and roadsides; generally in damp rich soil. When this plant comes in contact with the skin it causes welts or inflammation.