This close relative of ciliare has a similar range in southeastern states, and there is much overlap of habitats. Ecological differences remain uncertain, but marilandicum appears to be centered on more acid infertile soils. It differs morphologically from ciliare as follows (Isely 1990; W): petioles 10-25 mm long (versus 1-5 mm); stem glabrous to sparsely uncinate-puberulent; leaves glabrous or with only a few scattered hairs (versus subappressed ouberulent to glabrate); leaflets with L/W mostly 1.2-1.5 (versus 1.5-2.3).