The inflorescence architecture of Solanum acaule and related taxa of Solanum section Petota (Solanaceae)

In this morphological study a special and yet unrecorded inflorescence type is described in the polyploid series Acaulia (Solanum sect. Petota) and compared to those of other tuber-bearing Solanum species. This inflorescence can be characterized as a monochasium with a strongly reduced peduncle and one or two ‘extra’ flowers in the axil of the subtending leaf. Species showing this inflorescence architecture have a rosette-habit, which is correlated with the high altitudes in the Andes where they occur naturally. ‘Extra’ flowers and other inflorescence architectural traits such as the dimensions of pedicels, peduncles and corollas are discussed in relation to the taxonomy of Solanum sect. Petota species, their habitat and breeding behaviour.