Monoec. herb with rather slender stems, simple to much-branched, up to 6 dm. tall, sparsely clad in stinging hairs. Lvs 2-5 × 2-5 cm., on petioles up to 7 cm. long, rather closely to sparsely clad in stinging hairs; lamina thin, ovate to broad-ovate to deltoid, glab. except for a few stinging hairs, truncate to subcordate at base, coarsely serrate-dentate, sts incised; teeth acute to apiculate, 4-mm. or more long, sinus obtuse to acute. Stipules up to 1 cm. long, us. entire. Spikes up to 2 cm. or more long, solitary or paired, either with ♂ above, ♀ below, or bearing one sex only; per. glab. or nearly so. Achenes 1-1·5 mm. long, pale brown.

DIST.: N., S., St. Lowland to montane forest, forest margins and shaded open places throughout.

Type: Australian. The N.Z. forms need critical comparison with those of Australia and Tasmania.

Hooker's U. lucifuga was based on Tasmanian material.