Pollen morphology of Brazilian species of Vriesea (Bromeliaceae, Tillandsioideae)

• Published in: Grana Vol. 59; no. 2-3; pp. 203 - 225
• Main Authors: Santos, Valéria Leobina dos, Wanderley, Maria das Graças Lapa, Versieux, Leonardo M., da Luz, Cynthia Fernandes Pinto
• Format: Journal Article
• Language: English
• Published: Oslo Taylor & Francis 03-05-2020; Taylor & Francis Ltd
• Subjects: Analogies; Anatomical structures; Brazil; Dimensions; monocotyledons; Morphology; Ornamentation; Palynology; palynotaxonomy; Phylogeny; Poales; Pollen; Species; Vriesea; Vrieseinae
• ISSN: 0017-3134; 1651-2049
• DOI: 10.1080/00173134.2019.1676305

As a contribution to the infrageneric delimitation in the genus Vriesea pollen morphology of 17 species of the genus is described, with original data for 14 of the species. The pollen grains are heteropolar, with ellipsoidal amb, monosulcate, sulci marginate, reticulate with calota microreticulate or psilate-perforate. Variations in the dimensions of the structures, presence or absence of microreticula surrounding the lumina of the reticulum, type of ornamentation on the equatorial calota, difference in the exine thickness, and walls simplecolumellate or duplicolumellate, have helped in the separation of groups, and were important for the Palynotaxonomy of the genus. Proximity between species previously grouped by vegetative, reproductive and/or anatomical structures similarity, was confirmed for V. friburgensis and V. neoglutinosa, and for V. medusa and V. nanuzae. Vriesea bituminosa and V. neoglutinosa have demonstrated to share palynological similarities, although belonging to different sections, Xiphion and Vriesea, respectively. The pollen grains of V. flava and V. philippocoburgii, both from section Vriesea, were very similar, despite neither presenting similarities in the reproductive characters nor a close molecular phylogenetic relationship, thus suggesting a convergent evolution for this character. Such findings confirm the weakness of the delimitations of these two sections reported by previous studies. Our results allowed an improved morphological characterisation of genus Vriesea and could contributed to a biossytematic approach towards the resolution of species complexes.