Forum Flora Germanica

Rhizomatous perennial 60 — 120 cm. Stems simple or with few branches, upright, sparsely hairy below, nodes hairy. Leaf-stalks 5 — 20mm, sometimes to 3.5 cm, blades 4 — 9 x 2 — 5 cm, ovate to broadly lanceolate, hairless above, densely white-hairy beneath, tip acute to acuminate, base from weakly cordate to wedge-shaped, margins toothed. Spikes 4 — 8, to 12 x 1.5 — 2 cm, very congested except for lowermost whorls; bracts 4 — 6mm, ovate, hairy. Calyx 4 — 7mm, tubular, hairy, green at base, becoming purple, teeth 1 — 2 mm, narrow, more or less equal, purple. Corolla 7 — 10 mm, hairy, purple or bluish, lips minutely toothed. Nutlets yellowish brown, 1.2 mm, hairs white. NC North America. H3. Summer.