Solanum rigidum Lam.

Knapp, Sandra, Vorontsova, Maria S. & Prohens, Jaime, 2013, Wild Relatives of the Eggplant (Solanum melongena L.: Solanaceae): New Understanding of Species Names in a Complex Group, PLoS ONE 8 (2), pp. 1-12 : 10

9. Solanum rigidum Lam. , Tabl. Encycl. 2: 23. 1794.

Solanum latifolium Poir. , Encycl. (Lamarck) 4: 303. 1797.

Distribution. Endemic to the Cape Verde Islands; a few old collections known from Barbados and Antigua were probably introduced via ships carrying enslaved Africans from the Cape Verdes to the Caribbean; found along washes and at roadsides, sea level to 1000 m elevation.

This species has long been known as S. fuscatum L. , and was thought to be an American species introduced to the Cape Verde Islands [ 60]. Solanum fuscatum is a name of uncertain application [ 61, 62]; it has no type specimen and has recently been proposed for rejection [ 63] under the rules of the Code [ 51]. Morphology and molecular evidence (S. Stern and M.S. Vorontsova, unpublished) both show this species is a member of the eggplant clade and not an introduction from the Americas; it is endemic to the Cape Verdes and thus, despite its somewhat weedy nature, of conservation interest. The assumption that it was an American (New World) species has meant it has been treated as an invasive, rather than the endemic that it is. Its relationships to other eggplant relatives have not yet been rigorously assessed. Solanum rigidum resembles S cerasiferum morphologically but can be distinguished from it and other members of the group by its long triangular calyx lobes on long-styled flowers that are reflexed at the tips in fruit and the attenuate leaf bases.