Coefficient of Conservatism:
Coefficient of Wetness:
C. calceolus of Michigan Flora.
In a great diversity of habitats except the driest: moist forests (coniferous, mixed, deciduous), fens, meadows, borders of forests and clearings, often under cedar, and mostly in clearly calcareous soils.
Two somewhat intergrading varieties occur; var. pubescens (Willd.) O. W. Knight is large-flowered (lip (2.2–) 2.5–4.8 cm long), with greenish or yellowish to brown, often only modestly twisted lateral petals, and hairy upper sheathing bracts, and var. makasin (Farw.) Sheviak has a smaller flower (lip 1.5–2.9 cm), with dark purple-brown, strongly twisted lateral petals, and nearly glabrous upper sheathing bracts. Variety pubescens occurs throughout Michigan, often in drier forests (especially in areas of limestone bedrock), whereas var. makasin is found mostly in the lower half of the Lower Peninsula, with a few records north to Drummond Island and the western Upper peninsula, and occurs frequently in swamps, shrub thickets, fens, and wet meadows. Variety makasin was discussed as C. calceolus var. parviflorum in Michigan Flora.