The flora of the higher mountains of New Guinea has been the object of several extensive collecting trips in the past forty years. Until quite recently, however, a serious gap in our knowledge was the very scanty information available from the area between Mount Wilhelmina in the West and Mount Sarawaket and Mount Albert Edward in the East. Recently Mount Wilhelm, the highest mountain in this area and also the highest mountain in the Eastern half of the island, was visited on several occasions when botanical collections were made. The following collections are the most extensive ones and these are the only ones studied for this paper: In medio July, 1956 R. Pullen and myself spent ten days on the mountain with a camp near Lake Aunde as our base. In end July—early August, 1956 J.S. Womersley collected in the same area and some more collections were made in August, 1957 by R. G. Robbins. On these three occasions the mountain was approached from the East from Keglsugl in the Upper Chimbu Valley, along the valley locally known as Pindaunde. Alpine grassland comes down in this and other valleys to an altitude of ca 11000 feet (ca 3300 m), but on the steeper slopes and on the ridges the forest and shrubbery does not disappear until about 12500 feet (ca 3750 m). Pindaude, which down to 11000 feet (3300 m) is clearly of glacial origin, has a flat, ill-drained valley floor with peaty grassland, and fairly steep, locally rocky, lateral slopes which are covered with a subalpine forest, towards higher altitudes changing into alpine shrubbery. This shrubbery becomes patchy higher up and finally disappears at ca 12300 feet (ca 3690 m). Above that altitude, individual shrubs occur up to ca 12800 feet (ca 3840 m).