| 1 | Leaves ovate, to 6 cm long and 2¾ cm wide; nerves 3-6 pairs. Flowers solitary. |
| 1' | Leaves (narrowly) ovate to elliptic, 5½ -27 by 2-8½ cm; nerves 3-11 pairs. |
| 2 | Leaf-base cordate, base angle 90-180°. |
| 2' | Leaf-base not cordate. Base angle 25-90°. |
| 3 | Leaves 5½ -14 cm long. Petiole 1-2 mm |
| 3' | Leaves 16-18 cm long. Petiole c. 5 mm. |
| 4 | Leaves sparsely appressedly pilose beneath, but the indument inconspicuous and leaves seemingly glabrous. |
| 4' | Leaves densely appressed-hairy to sparsely more or less appressed-long-hairy beneath, indument always evident. |
| 5 | Twigs glabrous, rarely appressed-pubescent. Calyx often glabrous or nearly so, rarely appressed-pubescent. Style-base glabrous, rarely pilose |
| 5' | Twigs appressed-long-hairy, rarely glabrous. Calyx appressed-pubescent. Style-base pilose. |
| 6 | Twigs densely patently brown hairy (hairs often c. 2 mm). Leaves sparsely (appressedly) long-hairy beneath. Nerves 6-11 pairs. |
| 6' | Twigs densely obliquely pubescent. Leaves densely appressed-pilose beneath. Nerves 4-6 pairs. |
