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

Abstract

Th is paper presents a morphological analysis of the fl ower and fl oral 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 fl oral parts; the general confi guration 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. Th e characters were eff ective 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. Th e objective of this study was to provide fl oral morphological data useful for characterizing these three rare species, delimiting the genus and forming phylogenetic hypotheses.

An overview of secretion in floral bracts of Tillandsioideae (Bromeliaceae), with emphasis on the secretory scales

“…Trichomes on the inflorescence of certain bromeliads were suggested to produce visual signs for pollinators and dispersers ( Benzing 2000 ), but little is known about their significance beyond this putative function. Carvalho et al (2017) showed extreme polymorphism in floral peltate trichomes of three Dyckia species and found this character valuable for species delimitation. Recent findings showed that the mucilage covering the young inflorescences of Aechmea blanchetiana and Wallisia cyanea is produced and exuded by the peltate trichomes, and is possibly involved in mechanisms to cope with water-related stresses ( Ballego-Campos and Paiva 2018 ; Ballego-Campos et al 2020 ).…”