Palinotaxonomia de Rhabdoweisiaceae Limpr. (Bryophyta) ocorrentes nas Américas

Abstract

The family Rhabdoweisiaceae Limpr. includes small to medium sized acrocarpic mosses that grow predominantly as tufts and usually occur on rocks and soil. The circumscription of the family is controversial, and its monophyly is supported by molecular data. The present work aims to carry out the palynological study of species of Rhabdoweisiaceae Limpr. occurring in the Americas and to interpret the relationships between the palynological and ecological strategic characteristics of the species studied, which belong to the genera Amphidium Schimp.; Arctoa Bruch & Schimp.; Cynodontium Brid.; Dichodontium Schimp.; Dicranoweisia Lindb. ex Milde; Kiaeria I. Hagen; Oncophorus (Brid.) Brid.; Oreas Brid.; Oreoweisia (Bruch & Schimp.) De Not.; Rhabdoweisia Limpr. The spores were observed under light microscopy before and after acetolysis and under scanning and transmission electron microscopy. For the evaluation of the relationships between the spore morphology and the ecological strategies, the grouping analysis was performed considering the types of ornamentation elements, sporoderma polarity thickness, size condition, aesthetic area, life form and substrate. The species studied present small to medium spores, with radial symmetry and subcircular extent, are heteropolar or nonpolar. The sporoderm is formed by intina, exina and perina. The ornamentation elements allowed the characterization of four morphological types. Of the 23 species studied, nine, included in three genera present anisomorphic spores, being reported here for the first time. The spores of Amphidium Schimp. species have palynological characteristics that allow them to differentiate them from the other Rhabdoweisiaceae Limpr species. The most frequent patterns of ornamentation of the sporoderm surface were baculoid and granuloid; about 80% of the analyzed species present a distinct aperural area. Among the ecological characteristics, rock was the most frequent substrate, followed by soils and most species apressentm tuff as a way of life. The species of Rhabdoweisiaceae Limpr. analyzed in this work were grouped through palynological and ecological characteristics.