A frican spiny S olanum (subgenus L eptostemonum , S olanaceae): a thorny phylogenetic tangle

Although most diverse in the N ew W orld tropics, approximately 100 species of S olanum ( S olanaceae) are native to continental A frica and M adagascar. The majority of these are ‘spiny solanums’ (subgenus L eptostemonum ). We present here the first phylogenetic reconstruction of A frican and Madagascan species of S olanum subgenus L eptostemonum , with 62 of 76 species native to these areas, plus an additional seven species of largely A sian distribution, using internal transcribed spacer ( ITS ), waxy and trn T ‐ F regions. We identify monophyletic groups, many of which correspond to previously recognized units, although the large, traditionally recognized sections of O liganthes and M elongena are polyphyletic. These groups are distinguished from each other by their breeding systems, with members of O liganthes being hermaphroditic and M elongena andromonoecious. The phylogenetic relationships suggest multiple changes of breeding system between these two states, and observations of plants across their range indicate that there is considerable lability in this character. The A frican and M alagasy clades are largely geographically coherent, although there is evolutionary interchange between African vegetation types. All of the M adagascan endemics included in the analysis form a coherent group and probably represent an in situ radiation. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society , 2013, 173 , 176–193.