This is restricted to central and southern Appalachians, mostly on medium-acid soils in mesic to subxeric woods and edges. Its apparent rarity in Ky. is not explained. In morphology, it appears close to dioicum but differs as follows (FNA 3, W): roots bright yellow, tuberous (versus yellow to light brown, fibrous from stout caudex); cauline leaf subtending the lowest flowering branch sessile (versus with 3-7 cm petiole); plant flowering May-Jul (versus Mar-Apr); achenes borne on 0.7-2.5 mm long stipes (versus 0-0.3 mm). More glandular plants can also be confused with amphibolum, which has leaflets usually with 1-3 lobes; leaflets of coriaceum usually have 4-6 lobes (as in dioicum). Molecular analysis suggests a closer relationship with the pubescens group than with dioicum (Soza et al. 2013). Hybrid origin seems likely. Reportedly 2n = 70 and 140