Urtica dioica
Sp. Pl. 2: 984. 1753.
Herbs, perennial, rhizomatous, 5-30 dm. Stems simple or branched, erect or sprawling. Leaf blades elliptic, lanceolate, or narrowly to broadly ovate, 6-20 × 2-13 cm, base rounded to cordate, margins coarsely serrate, sometimes doubly serrate, apex acute or acuminate; cystoliths rounded. Inflorescences paniculate, pedunculate, elongate. Flowers unisexual, staminate and pistillate on same or different plants, staminate ascending, the pistillate lax or recurved. Pistillate flowers: outer tepals linear to narrowly spatulate or lanceolate, 0.8-1.2 mm, inner tepals ovate to broadly ovate, 1.4-1.8 × 1.1-1.3 mm. Achenes ovoid to broadly ovoid, 1-1.3(-1.4) × 0.7-0.9 mm.
Distribution
Alta., B.C., Man., N.B., N.S., N.W.T., Nfld. and Labr. (Nfld.), Ont., P.E.I., Que., Sask., Yukon, Ala., Alaska, Ariz., Calif., Colo., Conn., D.C., Del., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Mass., Md., Mich., Minn., Miss., Mo., Mont., N.C., N.Dak., N.H., N.J., N.Mex., N.Y., Nebr., Nev., Ohio, Okla., Oreg., Pa., R.I., S.Dak., Tenn., Tex., Utah, Va., Vt., W.Va., Wash., Wis., Wyo., Mexico, Eurasia.
Discussion
Subspecies 3 (3 in the flora).
Selected References
None.
Lower Taxa
Key
| 1 | Plants unisexual, staminate and pistillate flowers on different plants; leaf blades abaxially hispid, both surfaces with stinging hairs. | Urtica dioica subsp. dioica |
| 1 | Plants unisexual, staminate and pistillate flowers mostly on same plants; leaf blades abaxially bearing stinging hairs, otherwise glabrous, puberulent, or tomentose and moderately strigose, adaxially without (rarely with a few) stinging hairs. | > 2 |
| 2 | Stems glabrous or strigose, with a few stinging hairs; leaf blades abaxially glabrous or puberulent. | Urtica dioica subsp. gracilis |
| 2 | Stems softly pubescent, also with stinging hairs; leaf blades abaxially tomentose to moderately strigose. | Urtica dioica subsp. holosericea |