General:
Perennial herb from a short stem-base with fibrous roots; stems erect, solitary, simple, usually bristly or spreading-hairy, 15-150 cm tall.
Leaves:
Basal leaves lacking; stem leaves opposite, lanceolate, pointed at the tip, 4-15 cm long, 1-4 cm wide, sharply toothed, sometimes shallowly lobed, rarely with lobes at the base, short-hairy, short-stalked, the stalks 1-2 cm long.
Flowers:
Inflorescence a flat-topped cluster of spikes 3-10 cm long with many flowers; corollas blue to violet, 2.5-5 mm long, lobed, the lobes about 1/3 the length of the tube; bracts inconspicuous; calyces egg-shaped, 2.5-3 mm long.
Fruits:
Nutlets, 1.5-2 mm long, smooth or faintly lined.