| 1 | Leaf blade foliolate (in T. wawrae sometimes partly or all simple) |
| 1' | Leaf blade simple |
| 2 | Leaf blade 3-foliolate, membranous or chartaceous. Probract membranous, flat, sometimes caducous. Tendrils 1- or 2-branched. Rachis of male raceme 1-1.5 mm thick. Fruit ovoid, 6-9 cm long |
| 2' | Leaf blade 3-5-foliolate, chartaceous or coriaceous. Probract chartaceous, concave. Tendrils 2- or 3-branched. Male rachis 2-3 mm thick. Fruit narrowly ovoid, more than 10 cm long |
| 3 | Plant (sub)annual; monoecious. Leaf blade membranous, green-yellow on drying. Corolla 20(-30) mm diameter. Male bract 0.5-2 mm long, persistent or caducous. [Fruit small, ovoid, or much elongated, cylindrical in cultivated var. anguina.] Seeds with undulate margin |
| 3' | Plant (sub)perennial; monoecious or dioecious. Leaf blade membranous or chartaceous, green, brown, or blackish on drying. Corolla more than 30 mm diameter. Male bract 3 mm long or more. Seeds without undulate margin |
| 4 | Plant with fruit (and female flowers) |
| 4' | Plant with male racemes |
| 5 | Fruit globose |
| 5' | Fruit ovoid or ellipsoid |
| 6 | Fruiting pedicel of 2 differently structured and coloured parts. Leaf blade deeply 5(-7)-lobed. Seeds ± rounded at both ends |
| 6' | Fruiting pedicel of even colour and structure. Leaf blade ± 5-angular. Seeds chisel-shaped pointed at base |
| 7 | Seeds tumid (barrel-shaped or (sub)fusiform) (Fig. 91b) |
| 7' | Seeds compressed, rounded at both ends |
| 8 | Leaf blade 3-lobed, (1/4-)1/2 deep. Fruit ripening evenly red. Seeds 10-13 mm long |
| 8' | Leaf blade variously lobed. Fruit ripening red, mostly yellow striped. Seeds 15-20 mm long |
| 9 | Rachis 1-2 mm thick |
| 9' | Rachis 2-4 mm thick or more |
| 10 | Leaf blade usually finely hairy beneath. [Seeds tumid (barrel-shaped or (sub)-fusiform) (Fig. 91b).] |
| 10' | Leaf blade glabrous beneath. [Seeds compressed.] |
| 11 | Leaf blade ± 5-angular, with small glands near the insertion of the petiole. Bracts entire. Sepals (mostly) with narrow lateral lobes |
| 11' | Leaf blade unlobed or variously lobed. Bracts incised. Sepals entire, rarely few-lobed |
| 12 | Leaf blade deeply 5-7-lobed, usually with few glands 1-3 mm diameter |
| 12' | Leaf blade 3-lobed, 1/4-1/2 deep; glands scattered, less than 1 mm diameter |
