1	"Female flowers in fascicles, sometimes coaxillary with several males"	2
1	"Female flowers solitary"	4
2	"Female flowers mostly 3–7 per axil; central Western Australia"	"Cucumis variabilis"
2	"Female flowers mostly 1 or 2, rarely 3 or 4 per axil; northern and inland Australia"	3
3	"Seeds verrucose; mostly coastal E Malesia, northern Australia"	"Cucumis althaeoides"
3	"Seeds smooth; mostly inland Australia"	"Cucumis argenteus"
4	"Seeds pitted or verrucose"	5
4	"Seeds smooth"	8
5	"Fruit globose or subglobose"	6
5	"Fruit ellipsoidal, fusiform or ovoid-fusiform"	7
6	"Fruit 1–3 seeded; fruiting pedicel > 5 cm long; male inflorescence umbellate"	"Cucumis umbellatus"
6	"Fruit 6–25-seeded; fruiting pedicel <1 cm long; male inflorescences fasciculate"	"Cucumis althaeoides"
7	"Male inflorescence racemose; fruit strongly ribbed, the ribs scabrid"	"Cucumis costatus"
7	"Male inflorescence fasciculate, rarely racemose; fruit weakly ribbed, the ribs hispid"	"Cucumis queenslandicus"
8	"Fruit aculeate; aculei scattered or dense, soft or rigid"	9
8	"Fruit smooth or longitudinally ribbed, variously hairy, sometimes glabrescent"	11
9	"Fruit globose; aculei soft, scattered"	"Cucumis myriocarpus"
9	"Fruit ellipsoidal"	10
10	"Aculei dense, soft"	"Cucumis zeyheri"
10	"Aculei scattered, rigidly pointed"	"Cucumis metulifer"
11	"Leaves unlobed or shallowly 3- or 5-lobed; lobes<one third of lamina width; fruit with short antrorse hairs; native or naturalized"	"Cucumis melo"
11	"Leaves deeply 5-lobed; lobes > one third of lamina width; fruit sparsely pilose with spreading hairs, glabrescent"	"Cucumis picrocarpus"