Included in C. cryptolepis in Michigan Flora.

A newly recognized rare species of rich fens, endemic to the southern Great Lakes region in Michigan, and somewhat to the south in Indiana and Ohio.

This resembles robust individuals of Carex cryptolepis, but with significantly larger perigynia, these usually with a few teeth on the beaks.This is also a late ripening species, with perigynia not fully maturing until mid to late July.