This northeastern species occurs locally in the Southern Appalachians (W). The only confirmed Ky. records are from the Cumberland Mts.,perhaps LEWI (M. Wharton #5437 at USF) and recent records of V. Voellker (NP) from BOYD and ELLI (see iNaturalist). B collected it only on Big Black Mt. in HARL (US); see also notes in Hitchcock & Chase (1950). In Tenn., it is known from a few northeastern counties adjacent to Ky. and Va. (TENN). There have been many dubious or erroneous records in southeastern states (K); the uncertain records mapped here (and many records in FNA 25) need to be rechecked. D. latifolium is close to boscii (spikelets 3.8-5.2 mm) and commutatum (spikelets 2.2-3.2 mm), appearing intermediate in spikelets and other characters, including sometimes slightly bearded nodes (FNA 25). See also notes under clandestinum, which has often been confused. Recent analysis of DNA suggests that latifolium may be polyphyletic, but no segregates have been named (Majure et al. 2023).