| 1 | Leaves deeply 3-lobed, in shape often reminding of the letter 'W |
| 1' | Leaves entire. |
| 2 | Leaves villous or densely tomentose on the undersurface. Perianth with the tube bent backward and contacting closely laterally with the utricle; limb rim-like, obscurely 3-lobed |
| 2' | Leaves shortly or minutely hairy beneath. Perianth straight or slightly curved; limb distinctly 3-lobed or 1-lipped. |
| 3 | Flower buds with a distinct, long tail-like apex c. 20 mm long (easily broken when dry). Limb distinctly 3-lobed. Capsules oblong or ellipsoid, 5.5-9 by 3.5-4 cm, strongly 6-ridged. (Seeds not winged, rather smooth on both surfaces) |
| 3' | Flower buds without a long tail-like apex. Limb 1-lipped. Capsules short-cylindric, subglobose, slightly pyriform, or oblong, 2-4 by 1.5-3 cm, often slightly 6-ridged. |
| 4 | Leaf base obtuse, sometimes slightly cuneate, rarely truncate. Seeds not winged. |
| 4' | Leaf base cordate. Seeds winged. |
| 5 | Leaf veins and veinlets closely reticulate, densely covered with minute hairs beneath (examining with a handlens or under the dissecting microscope). Perianth lobes obovate-oblong, 25-30 by 10 mm, longitudinally reflexed at anthesis. Seeds 4-5 by 4 mm (incl. the c. 0.6 mm broad wing) |
| 5' | Leaf veins and veinlets loosely reticulate, sparsely shortly hairy or (nearly) glabrous beneath. Perianth lobes lanceolate to narrowly lanceolate, 20-30 (-40) by 6-8 mm, not longitudinally reflexed at anthesis. Seeds 8.5-10 mm long and wide (incl. the c. 2 mm broad wing) |
