Cypripedium arietinum

Cypripedium arietinum

Vulnerable  (NatureServe)
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Cypripedioideae
Genus: Cypripedium
Species:
C. arietinum
Binomial name
Cypripedium arietinum
R.Br. (1813)
Synonyms
  • Criosanthes arietina (R. Br.) House (1905)
  • Criosanthes borealis Raf. (1818)
  • Arietinum americanum L.C. Beck (1833)
  • Cypripedium arietinum f. biflorum P.M.Br. (1995)

Cypripedium arietinum, the ram's head lady's slipper, is a rare terrestrial orchid that grows in lightly to heavily shaded areas with calcareous soils. It is characteristic of the alvars around the Great Lakes in North America]. In Canada, it is found from Quebec to Saskatchewan, plus an isolated population in Nova Scotia, where it grows on gypsum based soils, 330 km away from the nearest population in Maine.