Flower and floral trichome morphology of species of Dyckia Schult. f. (Bromeliaceae, Pitcairnioideae), and their importance to species characterization and genus taxonomy

摘要

This paper presents a morphological analysis of the flower and floral trichomes of three rare species of Dyckia : Dyckia ibicuiensis , D. polyclada and D. racinae . Flowers at anthesis were collected from natural populations and subjected to morphometric and microscopic analysis. Among the most representative features for Dyckia are: morphometrics of individual floral parts; the general configuration of the androecium and gynoecium; the degree of fusion of the stigmatic lobes; the morphology of the ovules, especially in relation to the chalazal appendix; and the presence and constitution of peltate trichomes in the perianth, which exhibited a polymorphism not previously reported for Dyckia . The characters were effective at describing each species, proposing phylogenetic inferences and recognizing infrageneric groupings. We propose two species groups, which are consistent with previous hypotheses about the relationships among the species of the genus. The objective of this study was to provide floral morphological data useful for characterizing these three rare species, delimiting the genus and forming phylogenetic hypotheses.