Abstract The morphology of a new species of Petalonema Berk collected under a saxicolous habitat at 2900 m above sea level in the Singalila Range, Eastern Himalayas, during the Botanical Expedition of May 1974, was critically studied and named as Petalonema borzii sp. nov. The same alga was collected again on 28 Nov. 1982 from the Singalila Range at an altitude of 2500 m above sea level.