This southern Appalachian shrub is sometimes confused with other species in southeastern states, but it belongs in a distinct section of the genus. As well as its distinctive united styles and non-caudate seeds (Hu 1954-55), hirsutus has exposed axillary buds (most clearly in long-shoots), whereas the other species have buds enclosed by the petiolar base (W); also, its young twigs are densely hairy (versus glabrous or perhaps thinly hairy). Compared to pubescens and intectus, flowers are relatively small (FNA 12): with petals 5-13 x 4-13 mm (versus 12-21 x 8-12 mm), and with ca. 15-35 stamens.(versus 20-50). In Ky. hirsutus is known only from calcareous cliffs along the Cumberland Rv. and its tributaries, plus a few sites on or near Pine Mt. (BELL, HARL, WHIT). Included here is P. sharpianus Hu, which is a less pubescent form not considered significantly distinct in recent treatments (FNA 12, W); there are colls. at GH that were annotated by Hu as this taxon, from PULA ("Cox Bend of South Fork") and WHIT("shady cliff northeast of Jellico").