Contribution to the flower structure of Sararanga (Pandanaceae)

Abstract

In Sararanga, the fruit is a berry as in Freycinetia. The testa comprises a lignified outer integument with several cell layers, and an unlignified inner integument with two cell layers. Abortive fruits are frequent; they correspond to normal fruits that do not have carpels and sometimes have a lateral process that suggests an abortive carpel. The staminate flowers have a pistillode as in Freycinetia. The anther walls have 1–3 cell layers with endothecial thickenings, one layer in the distal part, 2–3 layers in the proximal part, as in Pandanus. Thus, within the family Pandanaceae, Sararanga has an intermediate position between Pandanus and Freycinetia. Generally speaking, there is a gradient in the vascularization of the bracts on the inflorescences: upper bracts are unvascularized, lower bracts vascularized. Anatomy suggests that the cupules are a perianth.