Published online by Cambridge University Press: 24 August 2012
Morphological and chemical studies of Hypogymnia from the Himalayas revealed one new species, three species new to the region, and a previously unrecognized synonym. Hypogymnia crystallina, distinguished by its rimmed holes in the lobe axils, a pruinose disc, POL+ epihymenium, and distinctive chemistry (zeorin, hypoprotocetraric acid, usnic acid and atranorin) is described as new. Hypogymnia pseudohypotrypa (Asah.) A. Singh is synonymized with H. thomsoniana and a second location is reported for the recently described H. sikkimensis. Hypogymnia bitteri, H. mundata, and H. subarticulata are reported as new to India. A total of 17 species of the genus Hypogymnia are accepted for the Himalayan region of India and Nepal, with one additional species from southern India. A key is given to the species known from this region.