Mapping is provisional. This midwestern species of dry prairies and rocky glades appears superficially close to ravenelii and the more widespread oligosanthes sensu lato (with scribnerianum). However, initial analysis if DNA suggests that malacohyllum (like ravenelii) may be nested wthin the acuminatum complex (Majure et al. 2023). All of these species may intergrade (FNA 25). Typical malacophyllium has "both surfaces velvety pubescent" (FNA 25), but most colls. mapped here (excepf fromn CRIT) have sparsely hairy to largely glabrous upper leaf surfaces, as in ravenelii. However, these colls. do have distinctly smaller spikelets (2.5-3.2 mm long), shorter ligules often with two distinct lengths of hairs (0.5-3 mm), and less robust habit than ravenelii; see FNA 25 for details. Both ravenelii and malacophyllum differ from oligosanthes and scribnerianum in their more densely bearded nodes, and more densely hairy (velvety) lower blade surfaces. Their spikelets usually have sparse to dense papillose-based hairs; those of oligosanthes have just sparse simple hairs, and those of scribnerianum are glabrous.