Purpletop Vervain

Description

Herb 0.5-1.5(-2) m high; branches erect, conspicuously quadrangular, with prominent long hairs. Leaves sessile, narrowly ovate, 4-15 cm long, 0.6-3 cm wide, rugose, scabrous and - shortly hairy above, with longer hairs below; base - subauriculate and amplexicaul; margin coarsely and irregularly incised-serrate (entire towards base); apex acuminate. Inflorescence lax, terminal, corymbose spike-like; bracts equal to or longer than calyx; peduncle and bracts strongly glandular. Calyx 5-toothed, 2.5-3 mm long. Corolla blue to reddish purple, 2.5-3.5 mm long, scarcely longer than calyx; tube c. 2.5 mm long. Mericarps 1.3-1.5 mm long.