1a. Leaf-margin not scalloped or only finely toothed 2 b. Leaf-margin scalloped or conspicuously toothed 3 2a. Leaves 3-7 cm, elliptic to lanceolate, underside densely covered with hairs - P. atalantioides b. Leaves 2.5- 4.5 cm, oblanceolate to narrowly obovate, underside with few hairs or hairless - P. koidzumii 3a. Calyx and flower-stalks hairless 4 b. Calyx and flower-stalks covered with hairs 5 4a. Young shoots with persistent rusty brown hairs -P. crenulala b. Young shoots with greyish hairs, eventually hairless and dark reddish brown -P.rogersiana 5a. Underside of leaves densely grey hairy P. angustifolia b. Underside of leaves hairless or sparsely hairy when young 6 6a. Leaves elliptic to ovate-oblong, widest above the middle, underside hairless -P. crenatoserrata b. Leaves narrowly ovate-lanceolate, widest below the middle, underside hairy when young - P. coccinea