Lookalikes
In the Kenyan and north Tanzanian highlands Solanum aculeastrum can be recognised by its globose to elliptic or pyriform fruit less than two times longer than wide.
Solanum aculeastrum is a distinctive species unlikely to be misidentified.
In the Kenyan and north Tanzanian highlands S. aculeastrum grows together with S. phoxocarpum and can be distinguished by its lobed, ovate to elliptic leaves 8-15cm long and 1.5-2 times longer than wide (versus subentire elliptic leaves 6-8cm long and ca. 2.5 times longer than wide in S. phoxocarpum), globose to elliptic or pyriform fruit less than two times longer than wide (versus pear-shaped pointed fruits ca. two times longer than wide in S. phoxocarpum), and white flowers that are rarely mauve (versus mauve flowers in S. phoxocarpum).
In the Southern Highlands of Tanzania S. aculeastrum occurs together with S. thomsonii and can be distinguished by its 1(-3) fruits 3-5 cm long (versus 4-10 smooth berries 1.4-1.7 cm diameter in each infructescence in S. thomsonii), obtuse, sometimes rounded leaf lobes (versus lobes always rounded in S. thomsonii), and calyx 3-15 mm long with acute to apiculate lobes (versus calyx 10-15 mm long with noticeably acuminate lobes in S. thomsonii).