Taxonomic implications of pollen morphology for species of Passiflora L., subgenus Deidamioides (Harms) Killip (Passifloraceae)

Abstract

Deidamioides, one of the four subgenera proposed for the genus Passiflora, is distributed in South and Central America, with its species, until now having been grouped in five sections: Deidamioides, Mayapathanthus, Tryphostemmatoides, Polyanthea and Tetrastylis. Within the current delimitation, subg. Deidamioides is not clearly defined and has a very controversial taxonomic history. The taxonomic complexity of this subgenus has been discussed by some phylogenetic studies attempting to clarify its monophyletic status and the positioning of species within its sections. The main objective of the present study was to analyze the pollen grains of species of subg. Deidamioides with the aim of finding diagnostic characters that can corroborate the taxonomic positioning of its sections and species. Polliniferous material was acetolyzed, measured and described using optical and scanning electron microscopy. Four pollen types and two subtypes were established for the analyzed species based on apertural characteristics: Pollen Type I (Subtype I.1. Passiflora contracta, P. igrapiunensis and P. timboënsis; Subtype I.2. P. cirrhiflora, P. macdougaliana, P. tryphostemmatoides and P. ovalis); Pollen Type II (P. obovata); Pollen Type III (P. arbelaezii and P. gracillima); and Pollen Type IV (P. deidamioides). The results confirm recent proposals that subg. Deidamioides is polyphyletic, and that it possesses apertural characteristics similar to those of subgenera Astrophea, Decaloba and Passiflora.