1	Leaves glabrous on both surfaces	2
–	Leaves with at least some pubescence on either surface (this sometimes sparse along veins and midrib)	10
2	Inflorescence few-flowered (usually less than 10), unbranched (at most furcate in Solanum betroka)	3
–	Inflorescence many -flowered (more than 10 flowers), usually many times branched	5
3	Flowers appearing fasciculate and axillary; corolla usually somewhat campanulate; fruit orange; South Africa	Solanum guineense
–	Flowers not appearing fasciculate; corolla spreading or the petals reflexed; Madagascar	4
4	Leaves clustered on short shoots; calyx lobes deltate, not divided to base; dry forests	Solanum betroka
–	Leaves not clustered on short shoots; calyx lobes long triangular, divided to the base; wet forests	Solanum truncicola
5	Flowers or fruits (or pedicel scars) in tightly packed groups on individual branches (these sometimes very short and the inflorescence appearing spicate)	Solanum terminale
–	Flowers spaced on the open inflorescence, often unevenly so	6
6	Leaves clustered on short shoots	Solanum betroka
–	Leaves spaced along the stem	7
7	Anthers opening by pores that elongate with age; mountains of continental Africa	Solanum runsoriense
–	Anthers opening by delineated pores that do not elongate with age; Madagascar	8
8	Leaves fleshy, thick and coriaceous, the venation not visible in dry specimens; fruit with thick pericarp (woody?)	Solanum myrsinoides
–	Leaves membranous to coriaceous, not markedly thick and fleshy, the venation visible in dry specimens; fruit with thin pericarp, the seeds visible through the berry wall	9
9	Petioles with long, simple trichomes (these not extending to the lamina); seeds 4-8 per berry; inflorescence axis thin and delicate	Solanum trichopetiolatum
–	Petioles glabrous or with minute dendritic trichomes; seeds 20-40 per berry; inflorescence axis robust	Solanum madagascariense
10	Leaf trichomes simple (unbranched)	11
–	Leaf trichomes branched (dendritic to echinoid)	16
11	Inflorescence axis unbranched, the flowers closely spaced	12
–	Inflorescence axis branched, often many times so	13
12	Leaves clustered along stem; fruit orange; South Africa	Solanum guineense
–	Leaves more or less evenly spaced along shoots; fruit purple or black; Madagascar	Solanum truncicola
13	Flowers or fruits (or pedicel scars) in tightly packed groups on individual branches (these sometimes very short and the inflorescence appearing spicate)	Solanum terminale
–	Flowers spaced on the open inflorescence, often unevenly so	14
14	Stems strongly quadrangular; at least some leaves with shallow lobes; plants of seashore and dune habitats	Solanum africanum
–	Stems terete; leaves not lobed; plants of forests and forest edges	15
15	Leaf pubescence very sparse, confined to the midrib or near the petiole; flowers not heterostylous; Madagsacar	Solanum trichopetiolatum
–	Leaf pubescence variable, not very sparse, along veins and lamina; flowers heterostylous; mountains of continental Africa	Solanum runsoriense
16	Abaxial leaf surfaces with tufts of trichomes in the vein axils (domatia)	17
–	Abaxial leaf surfaces with trichomes on lamina and/or along veins, not with prominent tufts in the vein axils (domatia)	19
17	Inflorescence many times branched, open and with many flowers (>20); calyx lobes broadly deltate and extremely short; petioles to 4 cm long, thin and flexuous; Mayotte	Solanum macrothyrsum
–	Inflorescence furcate, more congested and with fewer flowers (<20); calyx lobes deltate, not extremely short; petioles to 2.5 cm long, thicker; Madagascar	18
18	Calyx lobes 0.8-2 mm long; inflorescences with 10-16 flowers	Solanum ivohibe
–	Calyx lobes 4-6 mm long; inflorescences with 3-10 flowers	Solanum sambiranense
19	Abaxial leaf surfaces evenly pubescent on veins and lamina	20
–	Abaxial leaf surfaces pubescent only along the veins and midrib, the trichomes not extending to the lamina	22
20	Anther pores lengthening to slits with age; flowers heterstylous; leaves evenly distributed along branches; mountains of continental Africa	Solanum runsoriense
–	Anther pores not lengthening to slit with age; flowers not heterostylous; leaves usually at least somewhat clustered on short shoots; Madagascar	21
21	Leaves densely pubescent with golden (when dry) loosely dendritic trichomes; flowers >2 cm in diameter; anthers 4-6 mm long; widespread in Madagascar	Solanum imamense
–	Leaves sparsely pubescent with white (when dry) congested dendritic trichomes; flowers 2 cm in diameter or less; anthers 3.5–4 mm long; dry forests of southern Madagascar	Solanum betroka
22	Inflorescence unbranched, with few (usually < 5) flowers; pedicels 1.8-4.5 cm long	Solanum humblotii
–	Inflorescence many times branched, with many flowers (more than 5); pedicels 0.8-1.2 cm long	23
23	Anther pores lengthening to slits with age; flowers heterostylous; pedicels with pubescence like the inflorescence rachis; mountains of continental Africa	Solanum runsoriense
–	Anther pores not lengthening to slit with age; flowers not heterostylous; pedicels always glabrous; Madagascar	Solanum madagascariense