中国木蓼属的研究兼论木蓼族的系统

 我国木蓼属有11种,3变种,其中特有种3个。本文通过对它们的形态,花粉等性状的研究,探 讨了属的系统位置,提出了木蓼族的演化系统。在分析了木蓼属的性状后,认为木蓼组Sect Tragopyrum(Bieb．)Meisn．较为原始,应置于刺木蓼组Sect．Atraphaxis之前。本文还研究了该属的地理分布,初步探讨了它的起源及现代分布格局的形成。

A Study of the Genus Atraphaxis in China and the System of Atraphaxideae (Polygonaceae)

The genus Atraphaxis is found mainly in gravel steppes, sandhills and stony slopes or desert, with only a few species in meadow or river valleys. In China there are two sections and eleven species (including three varieties), which are distributed mainly in the northwest, with a few in the northeast and the north. Characters of the genus were compared and analyzed in the present work. Outer perianth segments 2, small, reflexed in fruit, inner perianth segments 2 or 3, large, erected and enveloping the nut. The embryo is curved, but those in the other genera  of Atraphaxideae are straight.  The curved embryo  is  the primitive character, because most species of the order Caryophyllales are of a circular embryo, which is belived to be ancestral in the Polygonaceae. The Pollen ornamentations of Atraphaxis are striate or striate-reticulate, different from those of the other genera. A new system of the tribe Atraphaxideae in proposed in the present paper. Based on the character analysis of the species in China, the pres- ent  authors  believe  that  Sect.  Tragopyrum  is  more  primitive  than  Sect. Atraphaxis. According to the distribution, the genus Atraphaxis might originate in Kazakstan, where not only are most species found, but also the most primi- tive species, like A. muchketovii, as considered by A. N. Krasnov, are found. Central Asia is considered as the distribution centre and origin centre of thegenus Atraphaxis.