Rehder
Description
Lithocarpus pachyphyllus is a stone oak widely distributed across the eastern Himalaya and adjacent Southeast Asia, with records from China, India, Nepal, Myanmar, Bhutan, Thailand and Vietnam and a substantial occurrence base of around 229 georeferenced collections. It is a canopy and subcanopy tree of montane evergreen broadleaved forest, forming a conspicuous element of the laurophyllous oak-laurel belt on humid, well-drained slopes. The tree photographed at Ramman in West Bengal (India) at about 2250 m in May represents its characteristic position in the mid-montane cloud-forest zone, where Lithocarpus and Quercus species dominate the wet temperate forests of the southern Himalayan front.
It is an evergreen tree with a dense, rounded crown and grey, finely fissured bark. The leaves are coriaceous and pachyphyllous (thick-textured, as the epithet indicates), elliptic to oblong-lanceolate, entire-margined, glabrous and glossy above and dull beneath, with a prominent midrib and arcuate lateral veins. As in all Lithocarpus, the staminate flowers are borne in erect, rigid catkins rather than the pendulous catkins of true oaks, while the pistillate flowers are clustered at the base of the inflorescence axis. The fruit is a thick-walled nut seated in a woody cupule whose scales are typically arranged in concentric rings; the acorns are often densely aggregated along the rachis.
Lithocarpus is distinguished from Quercus chiefly by its erect staminate catkins and frequently aggregated, sessile fruits, features expressed clearly in this species. Its heavy, animal-dispersed acorns provide an important mast resource for montane wildlife, while the species contributes substantially to the structure and carbon stock of Himalayan oak forest. Although not currently of conservation concern across its broad range, local populations are reduced by timber extraction and the conversion of mid-elevation forest, making it a key indicator of intact wet temperate woodland.
Author: Rehder · Sources: POWO (Kew), GBIF, Flora of China Vol. 4, Flora of Bhutan Vol. 1, Flora of Nepal, Camus Les Chênes: Monographie du genre Lithocarpus