Oncophoraceae (Bryophyta): a palynological treatment of species occurring in the Americas.

Marcella De A Passarella,Andrea P Luizi-Ponzo

doi:10.1590/0001-3765202120201508

Marcella De A Passarella, Andrea P Luizi-Ponzo

Open Access

https://doi.org/10.1590/0001-3765202120201508

Copy DOI

Abstract

Oncophoraceae are acrocarpous mosses that predominantly grow as tufts or cushions and especially occur on rocks and soil. The recognition of Oncophoraceae as a distinct family, as well as its generic circumscription, is not consensus among authors, and the pursuit for new information to improve its characterization is incessant. The present work aims to characterize the spore morphology and ultrastructure of 19 species (eight genera) occurring in the Americas and to evaluate the relevance of palynological data to circumscribe species, contributing to support other palynological studies. Observations were performed under Light and Electron (Scanning and Transmission) Microscopes. A Cluster Analysis was performed in order to evaluate the meaning of the palynological data, especially concerning the establishment of the species circumscription. Spores are monads, small to medium sized (10.40 to 44.20 μm), radially symmetric, subcircular in amb, heteropolar or apolar; the surface is ornamented by granules, gemmae and bacula. Anisomorphic spores were observed in eight studied species and are reported herein for the first time. The Cluster Analysis shows two groups with low similarity, which primarily differ by the polarity of the spores. The circumscription of Kiaeria and Cynodontium is corroborated by palynological characterization and endorsed by Cluster Analysis.

Highlights

IntroductionSmall to medium sized, growing in tufts or cushions, rarely pendant, on rocks or soil, and less frequently on trees
Our results demonstrate that the species of Cynodontium studied are included in a single morphological type of spores, supporting the taxonomical interpetation of these species
The small size of the spores indicates the importance of Scanning Electron Microscopy (SEM) observations to refine the description of sporoderm of these species

Summary

Introduction

Small to medium sized, growing in tufts or cushions, rarely pendant, on rocks or soil, and less frequently on trees. The stems are short, simple or sparingly branched; the leaves are lanceolate to narrow-lanceolate and oblong at the base. The capsules are immersed to exserted, ovoid to pyriform; the peristome is simple, having 16 teeth (Frahm 2002, Frey & Stech 2009, Goffinet et al 2008, Gradstein et al 2001, Stech & Frey 2008). The family includes about 100 species of wide distribution and high morphological variation, grouped in 13 genera: Arctoa Bruch & Schimp., Cynodontium Bruch & Schimp., Dicranoweisia Lindb. Oncophorus (Brid.) Brid., Oreas Brid., Oreoweisia (Bruch & Schimp.) De Not., Pseudohyophila Hilp., Rhabdoweisia Bruch & Schimp., and Symblepharis Mont. Oncophorus (Brid.) Brid., Oreas Brid., Oreoweisia (Bruch & Schimp.) De Not., Pseudohyophila Hilp., Rhabdoweisia Bruch & Schimp., and Symblepharis Mont. (Frey & Stech 2009)

Methods

Results

Discussion

Conclusion