Urtica L.
Glabrous between the stinging hairs
Leaves ovate to elliptic, mostly less than 5 cm long. Male and female flowers mixed in short axillary racemes. Monoecious annual. Widespread. Weed of waste and cultivated land. Introd. from Europe. Small Nettle Urtica urens
Leaves lanceolate to broad-ovate, mostly more than 5 cm long. Dioecious or monoecious perennial with male and female flowers in separate axillary racemes or panicles. Widespread. Forests; weed in waste places. Scrub Nettle Urtica incisa