| 1 | Fruits usually of two kinds, those of the lowermost forking of the inflorescence much narrower (probably seedless) than the rest, surmounted by 3 short or long horns or projections, and with conspicuous blocks or ridges of spongy tissue; branches of inflorescence in fruit usually inflating; bracteoles narrow and mostly green |
| 1' | Fruits all of one kind, surmounted by a ± symmetrical coronate or inflated persistent calyx, or calyx represented by an oblique tube or fan or simple, flattened, greenish tooth or rim; or calyx ± absent; spongy tissue absent; inflorescence branches not inflated in fruit (except occasionally in V. muricata); bracteoles various |
| 2 | Fruits with 3 short horns |
| 2' | Fruits with one or more long horns, visible early in flower |
| 3 | Fruits asymmetric, with one long and two short horns; bracteole margins ± entire |
| 3' | Fruits ± symmetrical with 3 long horns; bracteole margins clearly repand-dentate with a few rather glandular teeth |
| 4 | Fruiting calyx an inflated bladder-like vesicle with about 6 inflexed teeth around the ostiole, developing very early and detectable in flower; bracteoles very broad and very membranous and white-ciliate |
| 4' | Fruiting calyx otherwise; bracteoles narrower, ciliate or glabrous |
| 5 | Fruiting calyx ± coronate; ovary in fruit densely hairy, squarish-wedge-shaped, tapering to base in face view (i.e. with fertile loculus at the back); bracteoles obviously ciliate and with wide membranous margins |
| 5' | Fruiting calyx ± absent or reduced to a rim or fan, best developed on the fertile loculus, rarely an oblique tube; ovary in fruit glabrous or weakly hairy, rarely obviously hairy, and, if so, then ovary ovoid; bracteoles mostly green and ± glabrous, except for V. pumila with ciliate bracteoles |
| 6 | Fruit not more than 2 mm long overall, lobes of fruiting calyx weakly developed, not hooked, sometimes only ± 3 |
| 6' | Fruit larger, lobes of fruiting calyx strongly developed; usually terminated by a smooth indurate hooked point |
| 7 | Interior of calyx-cup glabrous, lobes 6; these distinctions generally visible in flower |
| 7' | Interior of calyx-cup pubescent, lobes up to 12, of different widths, sometimes only 6 but then with subsidiary hooks |
| 8 | Fruits longer than broad, incurved, with a distinct channel between the sterile loculi; fruiting calyx absent, fertile loculus projecting slightly beyond the sterile |
| 8' | Fruits about as long as broad or only slightly longer; fruiting calyx present as a distinct tooth or fan or rarely an oblique tube |
| 9 | Fruits almost globose, glabrous, with two large sterile loculi and calyx reduced to a tooth on the fertile loculus, sometimes spreading forwards to the sterile loculi as an irregular rim; bracteoles ciliate |
| 9' | Fruits ovoid, usually hairy, the two sterile loculi reduced to curving (often pale) ridges on the anterior surface, surmounted by a fan or oblique tube with venation clearly visible; bracteoles glabrous |
