Pycnanthemum tenuifolium Schrader. Phen: Jun-Aug; Sep-Oct. Hab: Bogs, wet meadows, moist to wet forests. Dist: ME west to MN, KS, and OK, south to FL and TX.
Origin/Endemic status: Native
Taxonomy Comments: A diploid and tetraploid species (n = 20 and 40).
Synonymy: = Ar, C, F, Fl6, GrPl, GW2, Il, K1, K3, K4, Mi, NcTx, NE, NY, Pa, RAB, Tn, Tx, Va, W, WH3, Chambers & Hamer (1992); = Koellia flexuosa – S, misapplied; = Pycnanthemum flexuosum (Walter) Britton, Sterns, & Poggenb. – G, Grant & Epling (1943), misapplied