﻿Quercus mangdenensis, a new species of Quercus (Fagaceae) from Kon Tum Province, Vietnam

Quercus mangdenensis Binh & Ngoc, sp. nov. (Fagaceae) is newly described from Mang Den Town in the central highland of Vietnam. The new species is characterized by lanceolate to oblong-lanceolate leaves with entire margin, 1–5-fruited infructescence, larger fruit size 6–10.5 cm long, broadly bowl-shaped cupules enclosing 1/5 of the nut, bracts of cupule entire and arranged in 5–7 rings, and cylindrical-ellipsoid and basally flat nuts 4.5–7.5 cm long. Quercus mangdenensis is morphologically similar to Q. bidoupensis Binh & Ngoc and Q. kontumensis A.Camus in having similar leaf shape, cuneate leaf base, and bracts arrangement in cupules. However, it differs from Q. bidoupensis and Q. kontumensis by cupules broadly bowl-shaped, much larger fruits, cylindrical-ellipsoid nut shape, and cupule enclosing 1/5 of the nuts. A description, photographs, and preliminary species conservation status of the new species are also provided.