Typical melanopoda occurs mostly in midwestern regions from Iowa to e. Tex., usually in open grassy swales. Plants east of the Mississippi Rv. tend to be distinct (Brunton & Britton 2006): their leaves are >1.5 mm wide at midpoint (versus <1.1 mm), usually whitish to occasionally dull brown (versus shiny blackish); megaspores are >400 (380) micrometers (versus <380), usually with bold distinct ornamentation (versus plain obscure); and their habitat is usually wooded swamps. The most distinct eastern plants, on the Coastal Plain and Piedmont from Miss. to N.J., have been named ssp. silvatica Brunton & D.M. Britt. Plants in Ky. have not been thoroughly reexamined, but some colls. from BULL (EKY, APSC) and HARD (APSC) appear at least transitional to silvatica.