Monographs Details: Cypripedium calceolus var. parviflorum (Salis) Fernald
Authority: Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Description:Variety Description - Smaller, with smaller, darker fls, the pet 3–5 cm, the lip 2–3 cm, chiefly of moist or wet low places, is northern and cordilleran, s. in our range to N. Engl., the Lake states, n. N.J., Pa., O., and at progressively higher elev. in the S. Appalachian Mts. to N.C. (C. parviflorum)