Abstract: In this paper, the chromosome numbers of two genera Nouelia and Leucomeris (Compositae) are first reported. In Nouelia insignis, 10 populations are studied. The result shows that the chromosome number in different population is consistent, 2n=54, which should be sexiploid.There is only one species of Leucomeris distributed in China. The chromosome numbers of Leucomeris decora is the same as Nouelia insignis 2n=54. Both genera have the same chromosome mumbers, which are also different from the other genera in tribe Mutisiinae. In cytological level, combining some morphological and distribution information, it probably implies that Nouelia is a natural group and there are close relationships between Nouelia and Leucomeris. Nouelia may be descendant of old plants. They developed polyploids for surviving in changing environments.

Key words: Chromosome

摘要： 对栌菊木属及白菊木属的染色体数目进行了首次报道.对栌菊木(Nouelia insignis Franch.)分布区内的10个居群进行了细胞学研究,染色体数目均为2n=54.白菊木属在中国分布的仅白菊木(Leucomeris decora Kurz)一种,对漾濞这个居群的细胞学研究表明,染色体也为2n=54.这两个属的基数可能x=9,它们可能为6倍体.结合帚木菊族已有的染色体报道及形态特征、地理分布等初步分析表明:栌菊木种内分化程度小,是一自然类群;栌菊木和白菊木可能有着较近缘的联系;栌菊木可能是古老孑遗植物的后裔,为适应环境而多倍体化,得以保存下来.

关键词: 染色体, 栌菊木, 白菊木