| 1 | Leaves deeply 3-lobed, in shape often reminding of the letter 'W' |
| 1' | Leaves entire. |
| 2 | Leaf base shallowly concave, subcordate, or almost truncate, rarely cuneate. Inflorescences with small, not amplexicaul bracts (c. 1.5 mm long). Seeds distinctly winged |
| 2' | Leaf base cuneate. Inflorescences with conspicuous amplexicaul bracts (7-10, rarely up to 15 mm long). Seeds not winged |
| 3 | Leaves villous or densely tomentose underneath, often concealing the surface (especially when young). |
| 3' | Leaves shortly, minutely, or sparsely hairy underneath (surface always exposed), or glabrous. |
| 4 | Perianth limb distinctly 3-lobed; lobes triangular, 3 by 4.5-6 cm, obtuse. (Fruit dehiscing from the apex downward; seeds strongly convex-concave) |
| 4' | Perianth limb rim-like, the limb 0.5-1 cm wide, obscurely 3-lobed. (Fruit unknown) |
| 5 | Leaf veins and veinlets closely reticulate or foveolate-reticulate, prominent beneath. |
| 5' | Leaf veins and veinlets loosely reticulate, distinct or obscure beneath. |
| 6 | Perianth without a stipe. Seeds not winged |
| 6' | Perianth with a distinct stipe of 3-5 mm. Seeds winged |
| 7 | Perianth without a stipe. Seeds not winged. (Leaves thin-chartaceous). |
| 7' | Perianth with a distinct stipe. Seeds winged. (Leaves chartaceous). |
| 8 | Leaves palmately 5 (-7)-nerved, papillate beneath |
| 8' | Leaves 3-curvinerved, with irregular (finely reticulate, wax) thickenings and scattered black dots (secretory cells) beneath |
| 9 | Leaf with the two basal lobes widely separate from each other (sinus 7-9 cm wide at the base). Perianth limb obovate-oblong, 10-14 mm wide; apex slightly retuse or mucronate |
| 9' | Leaf with the two basal lobes close to each other or often connivent at the base. Perianth limb lanceolate to narrowly lanceolate, 6-8 mm wide; apex acute |
