Compilation
Urtica heterophylla

Erect annual or short-lived perennial herbs to 1.5(2) m. tall, monoecious or dioecious by abortion. Stem sparsely branched, pubescent and covered with stinging hairs 7–9 mm. long, and with short stiff hairs. Leaves usually fallen from the lower part of the stem at anthesis, 10–20(25) x 10–18(23) cm., ovate to cordate but extremely variously lobed or divided (lamina of the younger leaves usually the least divided); apices of entire leaves and of lobes acuminate; base cuneate, truncate or cordate; margin dentate (with 20–25 teeth on each side in undivided leaves), teeth fine to coarse; lamina not bullate, triplinerved, upper surface glabrescent except for the stinging hairs, lower surface pubescent and with stinging hairs on the nerves. Petioles 3–15 cm. long, densely beset with stinging hairs. Stipules linear-lanceolate, fused for at least four fifths of their length, usually fallen at anthesis. Cystoliths dot-like. Inflorescences unisexual, cylindrical, up to 10 cm. long. Male inflorescences narrow, spicate panicles on peduncles to c. 2 cm. long; flowers on pedicels c. 1 mm. long, clustered, perianth 4–5-merous, tepals without dorsal appendages, rudimentary ovary present Female inflorescences thicker than the males, densely cymose, consisting of small dichasia 2–3 cm. long at anthesis but elongating to 10–15 cm. during ripening of fruit; flowers sessile, perianth c. 2 mm. long with 3 fused tepals, a free fourth tepal usually absent, ovary enclosed in perianth, stigma filiform. Achene up to 2 mm. long, ovoid to subcordate, compressed, rugose.