| | 2. All leaves entire or very shallowly lobed. |
| | | 3. Herb or short-lived small shrub. Berry 6-9 mm across, purple-black to black. |
| | | | 4. Berry shiny when mature. Seeds 1-1.5 mm long, 40-50 per berry. Stems often angled or winged…. | *S. americanum (Glossy Nightshade) |
| | | | 4. Berry dull when mature. Seeds 2 mm long, 25-35 per berry. Stems not angular.................................*S. nigrum (Blackberry Nightshade) |
| | | 3. Shrub to 2 m. Berry 10-15 mm across, orange-red................................................................................. | *S. pseudocapsicum (Madeira Winter Cherry) |
| | 2. Leaves some or most deeply dissected, some divided into individual leaflets | | |
| | | | (upper leaves often less deeply lobed or even entire). |
| | | 5. Annual or perennial herbs, often sprawling. Berry globular. |
| | | | 6. Leaves cut deeply, some into individual leaflets. Berry green to purple or red, 10-150 mm across. |
| | | | | 7. Aromatic herb, sticky with gland-tipped hairs. Roots not tuberous. Flowers yellow. Berry red......... | *Lycopersicon esculentum (Tomato) |
| | | | | 7. Non-aromatic herb, not sticky and hairs when present not gland-tipped. Roots develop | | |
| | | | | | | tubers (potatoes). Flowers white, pink to purple. Berry green or purplish........................................*S. tuberosum (Potato) |
| | | | 6. Leaves shallowly to deeply lobed but not divided into individual leaflets. | |
| | | | | | Berry whitish green, 8-12 mm across.................................................................................................*S. triflorum (Three-flowered Nightshade) |
| | | 5. Shrub to 4 m high. Berry egg-shaped. | |
| | | | 8. Stems often dark purple to black. Tips of petals notched. Berry yellow to orange-yellow……………..*S. laciniatum (Large-flowered Kangaroo Apple) |
| | | | 8. Stems dark green with raised lines. Tips of petals pointed. Berry orange to red................................. | *S. aviculare (Kangaroo Apple) |
| 1. | Leaves, stems and calyx with prickles or spines. |
| | 9. Calyx enlarged in fruit and partly or completely enclosing the berry. |
| | | 10. Sprawling herb with no large star-shaped hairs. Leaves moderately to deeply lobed |
| | | | | | but not cut into individual leaflets. |
| | | | 11. Leaves with few or no hairs................................................................................................................ | *S. hystrix (Afghan Thistle) |
| | | | 11. Leaves with many simple and gland-tipped hairs.............................................................................. | S. hoplopetalum | (Afghan Thistle) |
| | | 10. Erect herb to 1.5 m high. Lower leaves so deeply lobed that they form individual leaflets | | |
| | | | | | which in turn may be lobed. Star-shaped hairs and gland-tipped hairs present. |
| | | | 12. Flowers yellow. Berry black, 10 mm across....................................................................................... | *S. rostratum | (Buffalo Burr) |
| | | | 12. Flowers white to pale bluish purple. Berry red, 15-20 mm across..................................................... | *S. sisymbriifolium (Viscid Nightshade) |
| | 9. Calyx not or somewhat enlarged in fruit but not enclosing the berry. |
| | | 13. Perennial herb. Leaves entire or only shallowly lobed. Spines 2-5 mm long, few, only on stems. |
| | | | | | Berry 8-14 mm across........................................................................................................................ | *S. elaeagnifolium (Silver-leaved Nightshade) |
| | | 13. Shrub. Leaves moderately to deeply lobed. Spines to 10 mm or 15 mm long, common on | | |
| | | | | | stems, leaves and calyx. Berry 20-40 mm across. |
| | | | 14. Leaves dull green to silvery white, mostly 10-12 cm long. Flowers white to very pale |
| | | | | | | mauve, 30-40 mm across. Berry 30-40 mm across........................................................................ | *S. marginatum (White-edged Nightshade) |
| | | | 14. Leaves dark green, mostly 4-8(10) cm long. Flowers pale purple-blue, 15-30 mm across. | | |
| | | | | | | Berry 20-35 mm across................................................................................................................... | *S. linnaeanum (Apple of Sodom) |
| | | | | | | | | | | | | | * = Introduced species |