Stems tall and leafy, 1 ½ to 2½ feet high; leaves oval or elliptic 3 to 6 inches long, 1 ½ to 3 inches wide, pointed; sepals ovate-lanceolate, usually longer than the lip, yellowish or greenish yellow and striped with purple, petals narrower, usually twisted and elongated; lip much inflated, sub-globose, 1 to 2 inches long, pale yellow to bright yellow and sometimes with purple lines, a tuft of white, jointed hairs inside at the top; sterile stamen triangular, the thick, somewhat triangular stigma incurved.
In rich woods and thickets, Nova Scotia to Ontario and Minnesota, Alabama and Nebraska. This species is usually regarded as a form of Cypripedium parviflorum Salisbury, which has a small, laterally compressed lip one-half to three-fourths of an inch long. Since numerous intermediate forms occur it is probable that they represent forms of a single variable species.
Memoir 15 N. Y. State Museum
Yellow Or Downy Lady S-Slipper - Cypripedium pubescens