关于樟科润楠属和鳄梨属的分类界线问题

On the circumscription of Machilus and of Persea (Lauraceae)

讨论了润楠属MachilusNees与鳄梨属PerseaMill.的分类界线,认为两属的主要区别如下:在润楠属中,花被裂片相等或近相等,极少外轮明显短于内轮,在果期为纸质,极少为薄革质,伸长,强度反曲,极少张开与不反曲,几乎宿存,极少脱落,如果脱落时则内、外轮从基部完全脱落;花柱早落;分布亚洲热带及亚热带地区。而在鳄梨属中,花被裂片极不相等,外轮明显短于内轮,很少近相等,在果期为革质到木质,很少为薄革质,张开或直立,几乎不反曲,绝大部分宿存或内轮在距基部的1/3到1/2处脱落;花柱有时宿存;分布美洲。两属的界线清楚,不宜合并。把产于越南北部的PerseabalansaeAiryShaw和产于苏门答腊的P.sumatranaKosterm.转移到Machilus中,从而提出Machilusbalansae(AiryShaw)F.N.Wei&S.C.Tang和M.sumatrana(Kosterm.)F.N.Wei&S.C.Tang两个新组合。

The circumscription of Machilus Nees and of Persea Mill. （Lauraceae） has long been in dispute. In this paper, the generic boundary between Machilus and Persea is discussed. Machilus and Persea are two distinct genera different in some important characters. The perianth-segments in the genus Machilus are equal or subequal, rarely with the outer whorl conspicuously shorter than the inner whorl, and the segments at fruiting stage become chartaceous, rarely thinly coriaceous, elongated, strongly reflexed, rarely patent and not reflexed, almost persistent, rarely deciduous, and if deciduous, the perianth-segments of both outer and inner whorls fall from the base; the style is deciduous early. The species in this genus are distributed in tropical and subtropical Asia. On the contrary, the perianth-segments in the genus Persea are very unequal, with the outer whorl conspicuously shorter than the inner whorl, rarely subequal, and the segments at fruiting stage become coriaceous to lignescent, rarely thinly coriaceous, patent or erect, almost not reflexed, mostly persistent or falling 1/3 to 1/2 the distance from the base of the inner whorl perianth-segments, rarely wholly falling from the base; the style is sometimes persistent. The species in this genus are native to America. Two new combinations, Machilus balansae （Airy Shaw） F. N. Wei ＆ S. C. Tang and M. sumatrana （Kosterm.） F. N. Wei ＆ S. C. Tang, are proposed.