Verbena urticifolia var. urticifolia

Annual or perennial herb 40 cm - 1.5 m tall Stem: erect, branching near base, nearly hairless to minutely stiff-haired. Leaves: opposite, stalked, 5 - 20 cm long, more than 2 cm wide, egg-shaped and tapering to a pointed tip, coarsely toothed, nearly hairless or minutely stiff-haired beneath with hairs 1 - 1.3 mm long. Inflorescence: a branched cluster of numerous spikes, each ascending spike less than 7 mm thick, with flowers well separated along the spike. Flowers: white, subtended by 1 - 1.5 mm long bracts that are egg-shaped with pointed tips and hairs along the margin. The 2 - 2.3 mm long calyx has triangular lobes and appressed hairs, and the corolla is barely longer than the calyx and has blunt lobes. Fruit: four nutlets surrounded by the persistent calyx but exposed at the top, each nutlet 2 mm long with a wrinkled back.

Similar species: Verbena urticifolia var. leiocarpa is identified by its leaves with dense velvety hairs to 0.3 mm long, its minutely hairy calyx reaching 2 mm long, and its 1.5 mm long nutlets with shiny flat backs.

Flowering: June to October

Habitat and ecology: Common in fields, thickets, disturbed woods, shaded floodplains, and along old logging roads.

Occurence in the Chicago region: native

Etymology: Verbena is the Latin name for vervain. Urticifolia means nettle-leaved.

Author: The Morton Arboretum