Urtica dioica L.

  • Authority

    Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

  • Family


  • Scientific Name

    Urtica dioica L.

  • Description

    Species Description - Erect, rhizomatous perennial, usually simple, to 2 m; lvs serrate, acute or acuminate, 5–15 cm; stipules lance-linear, 5–15 mm; infls branched, many-fld, commonly exceeding the subtending petioles; fruiting cal 2 mm, pubescent; achene ovate, 1.5 mm. Nearly cosmopolitan, either as a native or an intr. sp., and highly variable. June–Sept. Var. dioica, native to Europe but well established in our range, is dioecious, weak-stemmed, and rather densely hairy, with mostly broadly ovate, cordate-based lvs with stinging hairs on both sides, and with the teeth commonly 5–6 mm deep; 2n=52. Var. procera (Muhl.) Wedd., the native phase, is usually monoecious, stouter and more sparsely hairy, with ovate to lance-oblong lvs that are seldom cordate at the base, with the stinging hairs commonly confined to the lower surface, and with the teeth averaging 2–3.5 mm deep; 2n=26 in ours. (U. gracilis; U. viridis)