First record of the family Micromitriaceae (Bryophyta) in Argentina

Abstract

The first record of Micromitriaceae Smyth ex Goffinet & Budke, represented by Micromitrium wrightii (Müll. Hal.) Crosby, is reported for northern Argentina. Micromitriaceae are a monotypic family of cleistocarpic, ephemeral mosses, separated from the Ephemeraceae J.W.Griff. & Henfr. by molecular analyses. This family is distinguished by the presence of a minute calyptra, a dehiscence line on the capsule, and the absence of stomata. Micromitrium wrightii is a cleistocarpic species characterized by the small size of the plants, linear-lanceolate leaves, the proximal ones weakly costate, irregularly rhomboidal and smooth laminal cells; a persistent calyptra, and large spores. Based on samples collected in Río Pilcomayo National Park reserve (Formosa – Argentina), the monotypic family Micromitriaceae, represented by Micromitrium wrightii, is reported for the first time in Argentina. A complete description with illustration under Light Microscopy and Scanning Electron Microscopy, and a dichotomous key to distinguish this taxon with related species of the Ephemeraceae, are presented here.