金缕梅科银缕梅属与帕罗堤属的亲缘关系——核糖体DNA ITS序列证据

本文对金缕梅科弗特吉族(Molinadendron和Matudaea除外)的细胞核核糖体DNA ITS片段进行了序列分析，在此基础上对该族的演化关系、尤其是中国特有属银缕梅属的系统位置进行了最简约分支分析。基本结果如下：其一，蚊母族和狭义的弗特吉族均不形成自己的单系分支，因此，支持Endress的处理，即合并两族为广义的弗特吉族；其二，银缕梅属同帕罗堤属有着密切的亲缘关系，支持形态学和解剖学结论；其三，根据该片段核苷酸序列的演化速率推算出的银缕梅属和帕罗堤属间分化时间为晚中新世。此结论大致与化石记录相符。

CLOSE RELATIONSHIP BETWEEN SHANIODENDRON AND PARROTIA (HAMAMELIDACEAE), EVIDENCE FROM ITS SEQUENCES OF NUCLEAR RIBOSOMAL DNA

The recently described genus Shaniodendron (Chang) Deng, Wei et Wang (Hamamelidoideae, Hamamelidaceae) is monotypic, narrowly distributed in eastern China, and on the verge of extinction. Morphological analysis puts this genus in the Fothergilleae sensu Harms, and implies that Shaniodendron is closely related to Parrotia C. A. Mey. In this study, sequences of the internal transcribed spacers of nuclear ribosomal DNA were analyzed for apetalous genera of the Hamamelidoideae to further evaluate the systematic relationships of Shaniodendron. The ITS-based phylogeny supported the combination of the Dis-tylieae and the Fothergilleae, thus recognizing the Fothergilleae sensu Endress. It also substantiated the close relationship of Shaniodendron and Parrotia. The estimated divergence time of Shaniodendron and Parrotia was the late Miocene, which agreed with the fossil record.