大头茶族的范围及族内属的界限

THE RANGE OF GORDONIEAE (THEACEAE) AND LIMITATION OF GENERA IN THE TRIBE

广义大头茶族几乎包括了整个山茶亚科的属,分群的界限不够明确,易于造成混乱,经过研究,作者所持的是狭义大头茶族的概念。考察这一族包括Polyspora, Gordonia和Laplacea三个属形态特征上的差异和洲际分布的事实,这三个属虽然有共同的祖先,但由于演化上的歧异,仍应作为独立的属看待。在划分属的界限上,苞被分化与否和花部其他形态的差异具有最重要的意义,花粉表面纹饰的差异也可作为一种依据。Polyspora种群划分也被讨论。

The Gordonieae in narrow sense includes three genera: Polyspora, Gordonia and Laplacea. The genera have clear and definite limitation in morphology. Firstly, the perules are not differentiated into bracteoles and sepals, as seen in Polyspora, but in other two genera have been done. Secondly, anthers are nearly basifixed in Laplacea; Thirdly, the styles are united and stigmas are five in Polyspora and Gordonia, but the styles of Polyspora are more longer than those of Gordonia, in Laplacea styles are very short and free, sometimes its ovary has 10 locules. Lastly, the extine of pollen possesses granulate ornamentation in Polyspora, reticulate in Gordonia and spinate-slender reticulate complex in Laplacea. The fact that the differences are revealed in morphologic characteristics, and the east Asia and America distribution expresses that attempt to reduce the three genera to sensu lato Gordonia is not appropriate. Otherwise, the distinctness of Polyspora among the population of species is disscused also.