The orchid is a perennial herbaceous plant of family Orchidaceae. The family is one of the largest among flowering plants, represented by 735 genera and 20 000 species worldwide. The genera hybridize readily. Most orchids are tropical and epiphytic (ie, grow in moss and debris on tree branches), but the 17 genera and 63 species native to Canada are terrestrial. Orchids are found throughout Canada. Some are arctic, eg, Habenaria albida and H. hyperborea; most grow in moist, wooded areas, eg, Cypripedium, Lady's Slipper, which has large, striking flowers varying from white through yellow to pink.

Calypso bulbosa has similar but smaller, delicate pink flowers. Some Spiranthes and Habenaria species have small, whitish, fragrant flowers in a spike. Two genera, Eburophyton (plant is white) and Corallorhiza (plant is yellow to purple), live on decaying vegetable matter. Attempts to transplant orchids from the wild usually result in the plants' death. Orchids are recognized internationally as endangered species, and trade in wild orchids is prohibited.