Castanopsis clemensii is locally known as Berangan in Malay or Kogopon in Dusun ethnic. This tree can reach up to 30 m tall and 50 cm in diameter. The bark is cracked or lenticellate or sometimes smooth in yellowish-white while the inner bark is fibrous in red-brown turning to dirty brown on exposure to sunlight. The sapwood is in pale yellow. The twigs are sparsely stellate-hairy, smooth or minute-lenticellate. This species has ovate stipules that are often persistent. Its elliptic leaves are coriaceous (having the texture of leather) and glabrous (smooth) on both surfaces with petioles of about 10 to 12 mm long. The male flowers are in clusters of 3 to 4 along the rachis with obtuse perianth lobes while the female flowers are solitary along the rachis with acute perianth lobes. There is only one ellipsoid seed with a thin wall in each obovoid or ellipsoid cupule (Soepadmo & Saw, 2000).

Castanopsis clemensii is endemic to Borneo. In Sabah, it is usually found in Ranau district and recorded by a few collections from Tenom, Tambunan and Keningau districts. In Sarawak, it is reported from Bario, Limbang (G. Murut) and Sri Aman districts. It grows in the primary lower montane forest, up to 1300 m altitude (Soepadmo & Saw, 2000).