Ecology: Puna; on soil, in part associated with shady rocks and cliffs. Elevation: 3500-4800 m (Peru: 4800 m, Bolivia: 4450 m, Argentina: 3500 m). Distribution: Peru, Bolivia, Argentina and Chile.
Brachymenium robertii is characterized by dense tufts to 10 mm high, plants small and fragile, leaves tightly imbricate, ovate-short acuminate, slightly plicate, concave, leaf margins entire, plane or reflexed below, costa subpercurrent to percurrent, laminal cells thin-walled, at margin not forming a border, rhomboidal to rhomboidal-hexagonal above, short rectangular below and narrowing toward the margin but not forming a distinct border and rhizoidal gemmae sometimes present, subspherical, densely papillose. This species was discussed by Ochi (1982); the type was collected by Fries in northwest Argentina (Moreno, Juyuy).
Specimens: PERU. Junín: Vitt 21633 (ALTA). BOLIVIA La Paz: Laguna Tuni, Lewis 82-331A (MO, det. H. Ochi, 1990). ARGENTINA. Juyuy: Fries 58a (PC).