摘 要 ：报道了润楠属一新种，狭基润楠Machilus attenuata F. N. Wei & S. C. Tang。本种与形态上相似的定安润楠M. dinganensis S. Lee & F. N. Wei的区别在于叶先端尾状渐尖或长渐尖，基部渐狭并略下延，幼叶上面无毛，下面疏被短柔毛；与西畴润楠M. sichourensis H. W. Li的区别在于叶较小，薄革质，倒披针形或椭圆形，长8~13 cm，宽2.2~4 cm，基部渐狭，侧脉在上面明显或略明显，下面明显。
Abstract:A new species of Lauraceae, Machilus attenuata F. N. Wei & S. C. Tang, is described and illustrated from Guangxi, China. It is closely related to M. dinganensis S. Lee et F. N. Wei, differing in its leaf apex caudate acuminate or long acuminate, base attenuate and slightly decurrent, and adaxial surface glabrous when young. It also resembles M. sichourensis H. W. Li, from which it differs in the leaves thinly coriaceous, oblanceolate or elliptic, smaller (8~13 cm long, 2.2~4 cm wide), gradually narrowed or slightly decurrent at base, and with lateral veins indistinct or slightly distinct adaxially and distinct abaxially.