Hypogymnia caperatica, a new species from the Hengduan Shan area (easternmost Tibetan region), with notes on some rare taxa from the greater Tibetan region and Bhutan

Hypogymnia caperatica, which contains caperatic acid as a major lichen substance in the medulla, is described as new from the Ilengduan Shan area (southeasternmost boundaries of the Tibetan plateau). The aliphatic acid caperatic acid is reported for the first time from the genus Hypogymnia. The occurrence of fatty acids in the genus Hypogymnia is generally discussed. The very rare lichen Hypogymnia sikkimensis., hitherto only known from two localities in Sikkim. as well as Hypogymnia diffractaica and H. hengduanensis are reported as new for the Kingdom of Bhutan. Hypogymnia capitata, known from the type and paratype specimens only, is reported from three further localities in the East Tibetan region.