臺灣植物誌中所記載的孛孛櫟（Quercus aliena Blume var. acutiserrata Maxim. ex Wenz.）是1924年由島田彌市首次於新竹縣紅毛所採集的標本，此後一直未曾有過野外的採集紀錄。2002年我們於紅毛南方3公里靠近牛牯嶺的鳳山地區再度找到該種殼斗科植物。然而，在觀察比較島田彌市及本次採集標本的形態特徵之後，我們認為這種植物應該是槲櫟（Q. aliena Blume）而非孛孛櫟。本文詳細描述該種植物，指明槲櫟及孛孛櫟之差異點，並提供台灣相關種類之檢索表。槲櫟目前已知的族群量很小，且生育地曾遭受人為的嚴重干擾。由於干擾的壓力目前仍然存在，所以我們建議有關單位應該儘速採取棲地保護的措施。
The first collection of Quercus aliena Blume var. acutiserrata Maxim. ex Wenz. in Taiwan was made by Y. Shimada in 1924 from Hongmao. Since then, no other specimen had ever been collected. Recently, this species was rediscovered from Fengshan (3 km south of Hongmao) in Hsinchu County. On closer studies it was found to be the typical variety of Q. aliena Blume rather than the name recognized by Shimada. The population of Q. aliena is quite small at that limited location, and is vulnerable to human impacts. Therefore, it is necessary to take steps to conserve the habitat as soon as possible. The taxonomic treatment, morphological descriptions, photographs and notes of the species are given here. A key to distinguish it from the other three closely related Taiwanese species is also provided.
