The Slipper Orchids
C. parviflorum var. pubescens: Greater yellow lady's slipper (Syn: Cypripedium calceolus var. pubescens, Cypripedium pubescens)
C. parviflorum var. parviflorum: Lesser yellow lady's slipper (Syn: Cypripedium calceolus var. parviflorum)
The species occurs from the eastern United States and Canada west to the Rocky Mountains north to Yukon and Alaska. Occurrence is infrequent in far western and southwestern US.
Cypripedium parviflorum grows in a variety of habitats from shady, damp forest understory of mixed deciduous and coniferous forests to open meadows and along streams in acidic soils.
Both varieties of Cypripedium parviflorum grow in multi-stemmed clumps. Plants at maturity bear 1 to 2 flowers and 3 to 6 leaves on each stem. The petals and sepals range from pale to deep magenta-brown and the lip is intense yellow with reddish spotty venation in its interior. Cypripedium parviflorum variety parviflorum tends to be smaller and less hairy than variety pubescens.