This occurs widely in east-central states but is largely restricted to woods on dry acid soils. Botanists in Ky. did not recognize the species until Wharton (1945) and Anderson (1947), although it had been described over a century before. Section Phyllostachyae has continued to provide suprises. Variation in willdenowii may still deserve further study; 2n = 62 and 78. "The Carex willdenowii group (C. willdenowii, C. basiantha & C. superata) differs from the other members of the section in having asynchronous spike production, resulting in a protracted fruiting season" (FNA 23; Naczi et al. 1998). C. basiantha is also expected in Ky., since it is known from most southeastern states, including Tenn. close to the state line (Ch). Its spikes have larger dimensions, and it occurs on damper, richer soils.