1	Leaf trichomes simple (unbranched) or absent	2
–	Leaf trichomes branched (dendritic or echinoid)	7
2	New growth of shoots completely glabrous	3
–	New growth of shoots pubescent (sometimes finely so)	5
3	Inflorescence unbranched, few-flowered; calyx lobes long triangular	Solanum truncicola
–	Inflorescence branched (sometimes only furcate); calyx lobes broadly deltate	4
4	Leaves fleshy, thick and coriaceous; pedicels 1.5–2.5 cm long; anthers ca. 7 mm long; berry usually apically pointed	Solanum myrsinoides
–	Leaves not fleshy, membranous to coriaceous; pedicels 0.4-1.1 cm long; anthers 2.5–4 mm long; berry globose or ellipsoid	Solanum madagascariense
5	Pubescence of new growth consisting of sparse, elongate, simple trichomes; petioles with sparse simple trichomes to 1.5 mm long	Solanum trichopetiolatum
–	Pubescence of new growth denser, the trichomes usually minute; petioles glabrous or with dense pubescence, not with elongate simple trichomes to 1.5 mm long	6
6	Leaves clustered on short shoots; inflorescences with <5 flowers; calyx lobes triangular; dry forests	Solanum betroka
–	Leaves spaced along the stem; inflorescences with >20 flowers; calyx lobes deltate to broadly deltate; widely distributed in wet forests	Solanum madagascariense
7	Abaxial leaf surfaces with tufts of trichomes in the vein axils (domatia)	8
–	Abaxial leaf surfaces with the trichomes on the lamina and/or along the veins, not in tufts in the vein axils	10
8	Calyx lobes foliaceous, often surpassing the corolla in flower	Solanum sambiranense
–	Calyx lobes not foliaceous	9
9	Calyx lobes broadly deltate, <1 mm long; inflorescences many times branched, with more than 20 flowers; Mayotte	Solanum macrothyrsum
–	Calyx lobes deltate, 0.8–2 mm long; inflorescences furcate, with 10–16 flowers; Fianarantsoa	Solanum ivohibe
10	Leaves pubescent on lamina surface; principal veins diverging 45° from the midvein	11
–	Leaves pubescent only along veins and midrib; principal veins diverging 60-90° from the midvein	12
11	Leaves densely pubescent with golden (when dry) loosely dendritic trichomes; flowers >2 cm in diameter; anthers 4-6 mm long; widespread	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	Solanum betroka
12	Inflorescence unbranched; pedicels 1.8-4.5 cm long, sparsely pubescent	Solanum humblotii
–	Inflorescence many times branched; pedicels 0.4-1.1 cm long, always glabrous (even when inflorescence rachis is pubescent)	Solanum madagascariense