4. Stachys tenuifolia Willd. (thinleaf betony, slenderleaf betony)

Pl. 443 f, g; Map 2003

Stems 30–100 cm long, glabrous or the angles sparsely pubescent with short, downward-angled, sometimes pustular-based hairs, often with a transverse line of longer, spreading hairs at the nodes. Leaves short- to long-petiolate, the petioles 5–35 mm long, those of the largest leaves more than 8 mm long. Leaf blades 2–12 cm long, lanceolate to oblong, oblong-elliptic, or occasionally ovate, angled or rounded at the base, mostly tapered to a sharply pointed tip, the surfaces glabrous or inconspicuously and sparsely pubescent with short, fine hairs. Inflorescences interrupted or very loosely continuous spikes, the nodes well-spaced to somewhat crowded. Calyces 4–7 mm long, the tube glabrous or with sparse, fine, spreading, often gland-tipped hairs, the lobes 1.5–3.5 mm long, glabrous or sparsely hairy along the margins. Corollas 10–13 mm long. 2n=34, 68. June–September.

Scattered nearly throughout the state (eastern U.S. west to North Dakota and Texas; Canada). Bottomland forests, edges of mesic upland forests, swamps, banks of streams and rivers, bases of bluffs, margins of ponds and lakes, bottomland prairies, moist swales in upland prairies and sand prairies, marshes, and fens; also ditches, roadsides, and moist, disturbed areas.