Abstract: Abstract The present paper reports the numbers of chromosome and karyotypes in 6 species of genus Tupistra. It is found that all species reported are diploid and the numbers of chromosome are 38. The formula of karyotype in T. wattii is 2n=2x=38=38m, and T. longipedunculata 2n= 2x= 38=28m+10sm, T. auran-tiaca 2n=2x=38=22m+16sm, T. fungilliformis 2n= 2x= 38 = 18m + 2sm+ 12st+ 6t, both T. chinensis and T. yunnanensis are 2n= 2x= 38 = 24m+14sm with karyotypes 2B, but they are different each other in the positions of sm chromoso-mes. The karyotypes of T. wattii, T. longipedunculata, T. aurantiaca, T. chinensis and T. yunnanensis are monomodal while T. fungilliformis is bimodal. Tupistra and Aspidistra are two related genera. Tupistra is more primitive and Aspidistra is more advanced. It seems that T. fungilliformis is a transitive taxon between Tupistra and Aspidistra.

Key words: Tupistra

摘要： 本文报道了开口箭属(Tupistra)6个种的核型，发现6个种皆为二倍体，染色体数目为38。他们的核型公式是：弯蕊开口箭(T．wattii)为2n＝2x=38＝38m；长梗开口(T.longipedunculata)为2n＝2x＝38＝28m＋10sm；橙花开口箭(T.aurantiaca)为2n=2x=38=22m+16sm;开口箭(T．chinensis)和云南开口箭(T．yunnanensis)皆为2n=2x＝38＝24m＋14sm，核型皆为2B型，但sm染色体的位置有所不同; 伞柱开口箭(T．fun－gilliformis)为2n=2x=38=18m+2sm+12st+6t。前述 5个种的核型由一型染色体组成，而伞柱开口箭的核型由二型染色体组成。开口箭属和蜘蛛抱蛋属(Aspisdistra)是亲缘关系接近的两个属，伞柱开口箭是开口箭属和蜘蛛抱蛋属之间的一个过渡类群。

关键词: 开口箭属, 蜘蛛抱蛋属, 核型, 染色体