Pycnanthemum muticum (Michx.) Pers.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Stems to 1 m, short-hairy, branched mainly above; lvs oblong or lance-oblong to lance-ovate, glabrous, obscurely serrulate or with a few low teeth, acute or acuminate, rounded at the base, the main ones 4–7 cm, on petioles 1–3 mm; lvs subtending the heads smaller and proportionately wider, velvety above, glabrous beneath; heads dense, hemispheric, 8–15 mm wide; bracts narrowly lanceolate, acuminate, hairy; cal densely short-hairy; its triangular lobes 0.5–1.5 mm; 2n=ca 108. Moist woods and meadows; Mass. and Vt. to Mich. and Mo., s. to Fla. and La.