| 1 | Leaves deeply 3-lobed, in shape often reminding of the letter 'W' |
| 1' | Leaves entire. |
| 2 | Leaf veins closely reticulate, prominent beneath. Fruits cylindric or oblong, 2.5-4.5 by 2-3 cm, minutely granular. Leaves cordate, auricles usually much overlapping; apex acuminate. |
| 2' | Leaf veins loosely reticulate and some crossbar-like, often slightly elevated beneath. |
| 3 | Perianth limb 6-lobed. (Leaf base cordate) |
| 3' | Perianth limb 3-lobed or 1-lipped. |
| 4 | Perianth without a stipe; limb 3-lobed. Seeds not winged. |
| 4' | Perianth with a distinct stipe; limb 1-lipped. Seeds distinctly winged. |
| 5 | Flower buds or perianth lobes with the apical 20-30 mm strongly contracted or narrowed and often tail-like when dry (easily broken). |
| 5' | Flower buds or perianth lobes without a tail-like apical part. Perianth lobes triangular, 5-6 by 8-10 mm, apex obtuse or retuse |
| 6 | Perianth lobes suborbicular, c. 10 mm ø, with an apical tail-like apex c. 20 mm long |
| 6' | Perianth lobes triangular to narrow-triangular, 35-50 by 12-14 mm at the base, apical 25-30 mm often tail-like when dry |
| 7 | Leaves glabrous. Perianth limb obovate or oblanceolate, 17-20 by 8-12 mm. Seeds (incl. wing) transverse-oblong, 6-11.5 by 12-16 mm, smooth on both surfaces |
| 7' | Leaves minutely hairy or sparsely short-hairy beneath. Seeds (incl. wing) triangular, 6-10 by 5-10 mm, usually verrucose on both surfaces. |
| 8 | Leaves triangular or deltoid in outline, minutely hairy beneath. Inflorescences 2-3 (-15) mm long; internodes condensed, obscure or invisible; bracts minute, c. 1 mm long. Perianth lobes oblong, c. 20 mm long |
| 8' | Leaves variable in shape and size, ovate, ovate-oblong, rarely suborbicular, sparsely shortly hairy beneath. Inflorescences 20-60 mm long; internodes spacious, distinct; bracts up to 10 mm long. Peri-anth lobes lanceolate, 20-30 (-40) mm long |
