This close relative of hystericina is widely scattered in wetlands across eastern North America (and also disjunct in some western states); but it is concentrated in cool temperate regions north of Ky. It is not verified from Ky. although there are records from adjacent counties in w. Tenn. (Ch), Mo., Ill., Ind. and Ohio (K). There is a coll. of C.W. Short (NY) labeled Ky., but with no other data. There may be a 1980s coll. from HARL (BEREA). The record from TRIG (Ellis et al. 1971) appears to have been based on a misidentified coll. of lurida (NCU). A recent immature coll. from HARD (by JC at barrens on Nacke Pike) may be this species or C. pseudocyperus L. Compared to hystericina (FNA 23), comosa has perigynia more or less reflexed when mature (versus spreading to ascending), leathery and uninflated (versus herbaceous and more or less inflated), compressed-triangular (versus terete to somewhat flattened), strongly and closely veined with most veins separated by less than 2 times their width (versus many veins separated by more than 3 times their width); longest beak teeth 0.7-2.1 (2.8) mm (versus 0.3-0.9 mm) and more or less outcurved (versus straight).