广义报春苣苔属 (苦苣苔科) 的染色体新计数及其分类学意义

报道了广义报春苣苔属14种3变种和7个未定名种的染色体数目，并对其近缘属——广义石山苣苔属的3个种也进行了细胞学研究。结合最近的分类处理和系统发育假设，对所得结果和以前发表的染色体数据进行了综合分析, 结果表明：广义报春苣苔属的染色体数目为2n=36，基数为x=18，表现出高度稳定性。染色体相对较小，以中间着丝粒和亚中间着丝粒染色体为主。尽管一些类群的染色体大小之间存在微小差异，但是染色体形态的均一性和染色体数目的一致性有力地支持分子系统学的研究结果。另外，相同的染色体数目及相似的染色体形态也表明广义报春苣苔属和广义石山苣苔属的亲缘关系较近，与分子系统学的结果一致。

New Chromosome Counts and Their Taxonomic Implicationsin Primulina sensu lato (Gesneriaceae)

Chromosome numbers can be helpful in understanding the taxonomy and phylogenetic patterns within plant groups. Primulina sensu lato (s. l.), a genus that has recently been redefined and expanded to include all species of Chiritopsis, two of Wentsaiboea and all of section Gibbosaccus of Chirita, has not been well documented cytologically. In the present study we determined the chromosome numbers of fourteen species, three varieties and seven undescribed taxa of Primulina s. l. using conventional rapid squash techniques. In addition, three species of its closest ally, Petrocodon sensu lato (s. l.), were also investigated cytologically. With the exception of Primulina tabacum, all counts are new. A high stability of chromosome number, 2n=36, based on x=18, was recorded in Primulina s. l. Chromosomes were relatively small in size, with mostly metacentrics and submetacentrics predominating. Although slight variation in chromosome size occurs among taxa, the overall homogeneity of chromosome morphology and pattern of basic chromosome number conforms with the results of molecular phylogenetic studies, which strongly support the monophyly of Primulina s. l., and also recent taxonomic treatment. Interestingly, the possession of the same chromosome numbers together with similar chromosome morphology, indicates that Primulina s. l. and Petrocodon s. l. are closely related, which is consistent with the molecular phylogeny of these genera.