This is a species of the lower Mississippi Valley and Gulf Coast that has been confused with the largely midwestern gymnospermoides (Sieren 1981, Nesom 2021a; Cr, FNA 20, W). Together, these two taxa contain a polyploid series; 2n = 18 (as in graminifolia), 36 (most gymnospermoides), and 54 (most leptocephala). Records of leptocephala from Ky. are mostly based on colls. of R. Athey (initially at MEM) that were identified by R. Kral (M), but may need further verification. There is also a coll. from HICK (Grubbs & Fuller 1991; GA, TROY but not yet been located at MUR). E. leptocephala is distinuished from gymnospermoides as follows (FNA 20; W, Nesom 2021b): leaves with numerous slightly raised, pale, translucent, blister-like pustules (versus with pustules absent or opaque); inflorescence array extending over 6-35% of total plant height (versus 25-60%). Differences in leaf width and L/W may not be reliable; but see FNA 20.