Quercus langbianensis is an uncommon oak tree species in the family Fagaceae. It is placed in subgenus Cerris, section Cyclobalanopsis, the ring-cupped oaks. These differ from other Quercus groups in that they have acorns with distinctive cups: usually with substantial rings, made-up of scales that have grown together. This species can be found in sub-tropical and tropical seasonal forests of Vietnam.
Synonymy A number of species names, previously considered synonyms,The Plant List: Quercus langbianensis Hickel & A.Camus (accessed 10/7/2017) are now considered to be valid.POWO: Quercus L. - 469 accepted species as of 18 April 2024 These very similar species are considered by Binh, Ngoc et al. (2018)Binh HT, Ngoc NV, Tagane S, Toyama H, Mase K, Mitsuyuki C, Strijk JS, Suyama Y, Yahara T (2018). A taxonomic study of Quercus langbianensis complex based on morphology and DNA barcodes of classic and next generation sequences. PhytoKeys 95: 37-70. to be a species complex; more information is available in Oaks of the World.Oaks of the World archive retrieved 16 April 2024
Other species names previously listed here were: Quercus baniensis A.Camus - Vietnam Quercus blaoensis A.Camus - Vietnam Quercus cambodiensis Hickel & A.Camus [synonyms Q. langbianensis subsp. Cambodiensis , Q. auricoma ] - Cambodia Quercus camusiae - Vietnam and China (mostly Yunnan).Flora of China, Cyclobalanopsis camusiae (Trelease ex Hickel & A. Camus) Y. C. Hsu & H. W. Jen, 1993. 法斗青冈 fa dou qing gang Quercus dilacerata Hickel & A.Camus - Vietnam Quercus donnaiensis A.Camus - Vietnam Quercus pachyloma [synonym Cyclobalanopsis pachyloma var. mubianensis ] - native to S. China and Taiwan.
Description Quercus langbianensis is an evergreen tree that reaches a height of up to 15 m. The leaves measure 70-140 (up to 170) x 25–40 mm, elliptical-lanceolate to oblanceolate, leathery and glabrous on both sides, with margins having numerous small teeth that are obtuse, wavy near the apex: which is acuminate to slightly caudate; petioles are 15–20 mm and hairless.
The acorns are sub-globose approximately 17–20 mm, covered with fine silky hair (sericeous), pale brown and ripening by September; scars are approximately 10 mm in diameter and convex. Their styles are persistent about 2 mm in diameter. Superficially, the cups are bowl-shaped, 8 x 20–25 mm approximately, enclosing 1/2 or 2/3 of the acorn. Outside and inside the reddish, tomentose acorn has a wall about 3 mm thick. The bracts are formed by 5 to 7 rings, with whole margins.
References
External links
Line drawings, Flora of China Illustrations vol. 4, fig. 378, drawing 5-11 at lower left