KEY TO SPECIES

1	Plants with prickles or with stellate hairs or both.		(2)
+	Plants with neither prickes nor stellate hairs (soft green emergences sometimes present on stems of S. americanum and S. nigrum).		(12)
2 (1)	Plants glabrous or with predominantly simple or rarely dendritic hairs, stellate hairs usually absent, if present on leaves, then mixed with simple hairs; fruit orange; seeds with a conspicuous circular wing, 4-6 mm across (including wings).		Solanum capsicoides
+	Plants with stellate hairs; prickles often present; fruits yellow or red, not orange, seeds unwinged, less than 4 mm across.		(3)
3 (2)	Plants unarmed; leaves entire; anthers stout, not tapering; inflorescences many flowered, flat or rounded panicles held upright above foliage in flower and fruit, much-branched.		Solanum erianthum
+	Plants mostly armed; leaves mostly dentate or lobed; anthers slender, tapering distally; inflorescences unbranched or 1-branched, rarely more, angling from twigs, held below foliage or along stems.		(4)
4 (3)	Fruit densely stellate hirsute with persistent tomentum; plants tomentose; calyx lobes nearly leaflike, more than 8 mm long; ovary tomentose overall		Solanum lasiocarpum
+	Fruit glabrous; plants variously pubescent; calyx lobes not leaflike, mostly less than 7 mm long; ovary with pubescence, if any, confined to the apex.		(5)
5 (4)	Leaves deeply many-lobed, more than xx cm long; calyx enveloping the fruit until maturity, copiously prickly.		Solanum lasiocarpum
+	Leaves entire or lobed to halfway, if lobed deeper, then leaves less than xx cm long; calyx directed away from the maturing fruit; unarmed or with few prickles.		(6)
6 (5)	Inflorescences mostly 1-3-branched; plants mostly more than 1 m tall.		(7)
+	Inflorescences unbranched; plants mostly less than 1 m tall.		(10)
7 (6)	Leaves entire, lanceolate or narrowly oblong; corolla less than 8 mm long.		Solanum luzoniense
+	Leaves subentire or 6- or 7-sinuate lobed, ovate-elliptic; corolla more than 8 mm.		(8)
8 (7)	Pedicel with simple glandular hairs, sometimes mixed with stellate ones; fruit yellow, more than 1 cm across; leaf lobes rounded		Solanum torvum
+	Pedicel with stellate hairs only; fruit yellow or red, less than 1 cm across; leaf lobes pointed.		Solanum lasiocarpum
9	Calyx lobes more than 1.5 mm long before splitting to form larger lobes; pedicels drying dark, sparingly tomentulose; fruit red; leaves mostly glabrescent above, sparingly lobed; seeds 2.5-3 mm across; upland species.		Solanum peikuoensis
+	Calyx lobes less than 1 mm long before splitting to form larger lobes; pedicels drying light, copiously tomentulose; fruit yellow; leaves mostly persistent-tomentose, saliently lobed; seeds 2 mm across; lowland species.		Solanum macaonense
10 (6)	Inflorescence a single flower; fruit more than 1.4 cm across, fruit yellow, brown, purple or black; flowers mostly andromonoecious or heterostylous.		(11)
+	Inflorescenceseveral flowered; fruit less than 1.4 cm across, fruit red or orange; flowers mostly bisexual.		Solanum violaceum
11 (10)	Fruit mostly much more than 4 cm across, variously shaped, seldom globose, green, white, black, pink, or brown, only yellow at extreme maturity.		(S. melongena L.-cultivated)
+	Fruit mostly less than 4 cm across, globose, green or yellow.		Solanum undatum
12 (1)	Shrubs, leaves entire.		(13)
+	Herbs or vines, leaves entire, toothed or dissected.		(14)
13 (12)	Several flowers appearing in a short inflorescenceat a node; fruits yellow; fruits yellow, less than 12 mm across; leavea glabrous.		Solanum diphyllum
+	One, rarely 2 flowers appearing at a node; fruits red, more than 12 mm across; leaves pubescent with branched hairs.		Solanum pseudocapsicum
14 (12)	Slender high climbing, often twining vines; fruits red.		(15)
+	Herbs, mostly erect, not twining or high climbing; fruits black or rarely green.		(17)
15 (14)	At least some leaves lobed or divided, leaves or leaflets basally pointed or cordate.		(16)
+	Leaves all entire, basally pointed.		Solanum pittosporifolium
16 (15)	Plants glabrate; filaments 2 mm long; ovary glabrous; fruit mostly more than 1 cm across; seeds 3-3.5 mm across; leaves basally pointed.		Solanum seaforthianum
+	Plants villous overall; filaments 1 mm long; ovary puberulent apically; fruit mostly less than 1 cm across; seeds 2 mm across; leaves basally cordate.		Solanum lyratum
17 (14)	Anthers less than 1.6 mm; corolla less than 5 mm long; fruiting calyx strongly reflexed; fruit mostly less than 8 mm across, shiny.		Solanum americanum
+	Anthers more than 1.7 mm; corolla more than 5 mm long; fruiting calyx mostly spreading or applied to the berry; fruit mostly more than 8 mm across, mostly dull.		(18)
18 (17)	Fruit less than 10 mm across; anthers mostly less than 2.5 mm long fruiting calyx mostly spreading or applied to the berry; plants evidently pubescent with erect and spreading hairs; leaves dentate or subentire, ovate to lanceolate.		Solanum nigrum
+	Fruit often more than 10 mm across; fruiting calyx reflexed from berry; anthers often more than 2.5 mm long; plants with inconspicuous, appressed hairs; leaves subentire, broadly ovate, diamond-shaped, or rounded.		(S. scabrum Mill.-rare cultivar)