Abstract: In the present paper, the somatic chromosome number and karyotype of the monotypic genus Theropogon (including the only species T. pallidus) in the tribe Convallarieae were investi-gated. The chromosome number in the root tip cells was counted to be 40, which is in accord with that reported by Kurosawa. The karyotype is given here for the first time and formulated as 2n=26m+12sm+2st(sat). The 9th pair of chromosomes have centromeres at the subterminal positons, with a satellite respectively on their short arms, and the satellites are longer than the short arms. The chromosomes decrease gradually in size from the largest to the smallest, so the karyotype is monomodal and belongs to Stebbins' 2B type. Compared with the other genera in the tribe Convallarieae, such as Convallaria, Reineckia, Rohdea, Tupistra and Aspidistra, Theropogon is different from them in its basic chromosome number, karyotype classification (especially from Speirantha, Aspidistra and those species of Tupistra with karyotype of 2C) as well as chromosome size, though its satellite chromosomes are similar to those of Speirantha, Rohdea, Tupistra a-ndAspidistra.

Key words: Theropogon

摘要： 本文报道了夏须草属（Theropogon）的染色体数目和核型。数目与Kurosawa的报道一致，为2n=40；核型为首次报道。核型公式为2n=26m＋12sm＋2st（sat）。第9对染色体为st幻染色体，短臂上具有随体，随体长于短臂。染色体从长到短逐渐变化，无二型性。核型类型为Stebbins的2B型，属于较对称的核型。与铃兰族另外6属比较，除基数不同外，夏须草属的染色体还显得相对较小，尤其缺少其它属通常都具有的第1对大型染色体。夏须草属的随体染色体与白穗花属、万年青属、开口箭属、蜘蛛抱蛋属的随体染色体在形态上相似，随体长于短臂。虽然夏须草属在染色体以及其它一些重要性状上都与铃兰族另外的属有区别，但本文作者仍然赞同汤彦承等的意见，认为在未进行全面的研究之前，不宜将夏须草属提升为亚族或转移至另外的族中。

关键词: 夏须草属, 核型, 系统位置