This recently described segregate of compressa is known from seasonally damp calcareous flats in Ala., Ga., Ky. and Tenn. (C.G. Smith et al. in FNA 23); it has also been reported recently from s, Mo. (Thomas 2017). E. bifida can be distinguished from compressa by its pistillate scales, which are all deeply bifid (versus at least the lower ones entire); styles are often bifid (versus all trifid), and seeds are often biconvex (versus all uncompressed). Also, its rhizomes are 3-5 mm thick (versus 2-3 mm), producing relatively tight clumps of culms that are highly compressed, with a width of 4-10 times thickness (versus 2-5 times). Culms tend to be wider overall (0.7-2.3 mm versus 0.2-1.8 mm). It is possible that a few Ky. colls. are intermediates, as found in Tenn. (TENN), but most plants previously known as compressa in Ky. are now referable to bifida. A mixed population apparently occurs along the rocky banks of the Little South Fork of Cumberland Rv. in MCRE and WAYN (dets. of G. Smith at KY). See also note on "acuminata" under elliptica.