Not mapped here, pending deeper study. Some colls. mapped here as lanuginosum are probably referable to implicatum, which may be the closest relative of lanuginosum (Thomas 2015). That taxon is widely reported from across eastern states except on the southeastern Coastal Plain. Largely following Thomas, implicatum differs in its largest vernal leaves mostly 5-6.5 cm x 4-6 mm (versus 6.5-12 cm x 6-12 mm); hairs on upper blade surfaces are longer (3-6 mm versus 1.3-3 mm), as are those on lower surfaces (0.8-2 mm versus 0.1-0.7); spikelets tend to be smaller (1.3-1.6 mm long versus 1.5-2 mm). Ladd & Thomas (2015) also noted: "a very unique reflexed curvature to the vernal stem leaves in late summer and fall." It tends to occur on more acid soils. However, R.J. LeBlond (in W) has not recognized implicatum as distinct.