This is a widely scattered eastern species, mostly in coastal or lacustrine regions, but FNA 23 did not include Ky. in the range. It was reported from the confluence of Big and Little Caney Creeks in ELLI by Cusick (1989), but the coll. needs to be rechecked (?NY, NCU). E. olivacea has been confused with intermedia in Ohio, where both species do occur. Distinction from typical E. flavescens (Poiret) Urban may be difficult in zones of overlap, but these taxa should be recognized at least as varieties (FNA 23) if not species (W). E. flavescens is a more southern (largely subtropical) plant with a higher chromosome number; 2n = 30 versus 20.