Many colonies of this orchid in the Canadian Shield Region, but very few farther south or east. Moist or dry woodlands. In the Ottawa Region, the largest colonies occur in swamps; usually only small numbers are found in forests.
Var. macrophylla tends to occur in more Deciduous conditions with relatively rich soil, compared to var. orbiculata, but still in areas of little herbaceous cover but thick layers of leaf mould. A more restricted and southern distribution, occurring south of the border to Wisconsin and South Carolina.

Height to 60 cm.
Leaves two, basal, sub-opposite, flat on the ground, orbicular,bluish-green above, silvery below; stem with few cauline bracts.
Raceme of up to 20 flowers.
Flowers greenish-white sepals, petals and lip white, spur translucent.
The two varieties are hard to differentiate in the field. Var. macrophylla has larger leaves and a much larger spur.

Both varieties are considered rare in Ontario and Quebec. May be confused with P. hookeri because of similar growing conditions and basal leaves. In Ontario, P. orbiculata tends to grow in moister woodlands, and blooms later, the leaves are more shiny, the scape is bracted, and the lips are blunt and directed downward rather than upwards and pointed as P. hookeri.

Orchids of Ontario
The Canadian Field-Naturalist
The Orchids of Bruce & Grey