Macromitrium nelliampathyanum sp. nov. (Orthotrichaceae: Bryopsida), a new moss species from the Western Ghats of India

Abstract

During bryological work in the Nelliampathy hills (Western Ghats, India), we collected an epiphytic Macromitrium with unistratose leaves in which cells in the distal 1/3 of the leaf are bulging but neither tuberculate nor papillose. The specimen did not fit morphologically with any other species of the genus worldwide. We performed a phylogenetic analysis based on trnL-F sequence data, and compared the morphology of this specimen with the related species of Macromitrium. Morphological and molecular evidence support the establishment of a new species of Macromitrium, M. nelliampathyanum Sajitha, Manju & J.Muñoz, which is described and illustrated. The new species can be distinguished from all congeners by the combination of the following morphological characters: (1) branch leaves strongly curled and flexuous along its costa when dry, unistratose, (2) cells in the distal 1/3 of the leaf bulging, with smooth walls, neither papillose distally nor tuberculate proximally, (3) a very small area at the juxtacostal extreme base of cells hyaline and larger, similar to the ‘cancellina’ in calymperoid mosses, (4) basal margins with a long, single row of 12–13 hyaline cells; (5) pleated calyptra covering ¾ of the globose capsule, with a few hairs at the beak, (6) peristome teeth reduced, consisting only of a low irregular papillose outgrowth, or absent, and (7) anisospory.