Didymodon hegewaldiorum (Pottiaceae), a new species from the Tropical Andes

Didymodon hegewaldiorum J. A. Jimenez & M. J. Cano, is described as a new Neotropical species from dry puna of Peru and Bolivia. It differs most saliently from other species of Didymodon Hedw. in its stems with hyalodermis and without sclerodermis, ovate to ovate-lanceolate and appressed leaves when dry, bistratose leaf lamina, plane margins throughout, and a short and straight peristome. Drawings, LM and SEM photographs of the most important characters are given, and possible confusion with other taxa, such as Didymodon australasiae (Hook. & Grev.) R. H. Zander, D. fuscus (Mull Hal.) J. A. Jimenez & M. J. Cano, D. minusculus (R. S. Williams) R. H. Zander and D. rigidulus var. subulatus (Ther. & E. B. Bartram ex E. B. Bartram) R. H. Zander, is discussed.