Urtica dioica L.

Rhizomatous, erect perennial, usually dioecious, rarely with a few fls of the other sex, moderately clothed in short-stalked stinging hairs, otherwise sparsely to densely hairy. Stems with few if any lateral branches, up to 1.5 m high. Lvs broadly lanceolate or ovate, acute to acuminate, usually cordate at base, occasionally truncate, coarsely serrate, (5)–6–20–(25) cm long. Petiole up to ⅔ as long as lamina. Stipules 4 per node, entire, 4–20 mm long. Racemes unisexual, up to 9 cm long. Perianth segments of ♀ fls very unequal, hairy; margins glabrous. Achene ellipsoid, light brown, c. 1.5 mm long.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]