a tall perennial herb; stems erect, 4-angled, striate, scabrid on the angles, otherwise glabrous; leaves opposite, sessile or subsessile, sheathing at the base, oblong, oblong-lanceolate or rhomboid-ovate, narrowed towards the base, more or less deeply trifid, pinnatifid or bipinnatifid, with the lobes acute or obtuse, coarsely inciso-dentate, adpressed puberulous or glabrescent, thin, 1–4 in. long; panicle terminal, much branched, wide, more or less leafy below, 1/2–1 1/2 ft. long; branches slender; spikes bracteate, very lax, slender, bearing numerous lilac flowers, distant below, crowded above, 6–9 in. long; bracts ovate, acute, with the midrib very prominent beneath, pubescent beneath, glabrous above, not exceeding 1 lin. long; calyx cylindric, minutely toothed, glabrous within, pubescent without, hispid on the ribs, about 1 lin. long; corolla-tube delicate, cylindric, about twice as long as the calyx; stamens inserted about the middle of the corolla-tube; ovary and style about 1 lin. long; cocci shortly oblong, striate, 3/4–1 lin. long. null
