Ecology: Open montane to puna; on soil and rocks. Elevation: 600-3000 m. Distribution: Peru: 3000 m; NW Argentina: 600-2400 m. World range: Endemic to the tropical Andes (Peru and NW Argentina).
Ecología: Montano abierto a puna; sobre rocas y suelo. Elevación: 600-3000 m. Distribución: Perú: 3000 m; NO Argentina: 600-2400 m. Distribución mundial: Endémica de los Andes tropicales (Perú y NO Argentina).
Didymodon buckii is distinguished by the dense tufted plants, stems to 1 cm, oblong-linear leaves 1.5-2.6 mm, acute apex channeled with the thickened apices often caducous, 2-3 stratose margins from apex to base, hyaline area of rectangular cells on the ventral costa surface, and ventral stereid present below midleaf. This new species, often found in disturbed sites, was found in association with Andina churchilliana J.A. Jiménez & M.J. Cano and A. pruinosa (Mitt.) J.A. Jiménez & M.J. Cano, Gertrudiella uncinicoma (Müll. Hal.) G.M. Suárez &Schiavone, Pseudocrossidium replicatum (Taylor) R.H. Zander, and Syntrichia fragilis (Taylor) Ochyra (Jiménez et al. 2018).