[Deam recognizes three varieties based upon differences in pubescence. More or less glabrous plants represent the typical variety. These are] infrequent in moist or dry woods and probably found throughout the state. [Variety brachycoma has puberulent stems in which hairs are about 0.5 mm long.] Our only specimen is from a woods about 12 miles northeast of Indianapolis now known as "Woollen's Garden of Birds and Botany." [Variety villicaulis has villous stems, hairs about 1-2 mm long. This variation is] infrequent, probably throughout the state in rich or dry woods.
Much like no. 1 [Osmorhiza claytonii (Michx.) C. B. Clarke], but the fls a little larger and more numerous in each umbellet, the styles at anthesis ca 2 mm, much exceeding the pet, in fr nearly straight and parallel, 3-4 mm; plants anise-scented; 2n=22. Moist woods; Que. to Sask., s. to Ga., Tex. and Colo., commoner s. and w. May, June. (Washingtonia l.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.