1	"Female flowers solitary"	2
1	"Female flowers in fascicles, sometimes co-axillary with several males"	10
2	"Seeds smooth"	3
2	"Seeds pitted or verrucose"	8
3	"Fruit aculeate; aculei scattered or dense, soft or rigid"	4
3	"Fruit smooth or longitudinally ribbed, variously hairy, sometimes glabrescent"	7
4	"Aculei soft"	5
4	"Aculei rigid, i.e. spinose"	6
5	"Mature fruit with aculei moderately dense to dense (about 20–100 per square cm); seeds 4-8.5 mm"	"Cucumis dipsaceus"
5	"Mature fruit with aculei sparse (about 5–10 per square cm); seeds 4–5.5 mm"	"Cucumis myriocarpus subsp. myriocarpus"
6	"Mature fruit with aculei moderately dense (about 10-30 per square cm); fruit ripening yellow"	"Cucumis anguria var. anguria"
6	"Aculei sparse (about 0.5–2 per square centimetre); fruit ripening orange–red"	"Cucumis metuliferus"
7	"Leaves unlobed or shallowly 3– or 5–lobed; lobes < one third of lamina width; fruit with short antrorse hairs"	"Cucumis melo"
7	"Leaves deeply 5–lobed; lobes more than one third of lamina width; fruit sparsely pilose with spreading hairs; glabrescent"	"Cucumis picrocarpus"
8	"Fruit globose or subglobose"	"Cucumis althaeoides"
8	"Fruit ellipsoidal, fusiform or ovoid fusiform"	9
9	"Male inflorescence racemose; fruit strongly ribbed, the ribs scabrid"	"Cucumis costatus"
9	"Male inflorescence fasciculate, rarely racemose; fruit weakly ribbed, the ribs hispid"	"Cucumis queenslandicus"
10	"Seeds (6–)9–15 per fruit, markedly verrucose to slightly verrucose"	"Cucumis althaeoides"
10	"Seeds 4–6 per fruit (rarely more), smooth to slightly verrucose"	"Cucumis argenteus"