中文摘要：

菊科紫菀属密毛系（Aster Series Vestiti Ling）含3个物种：密毛紫菀（A.vestitus Franch.）、灰枝紫菀（A.poliothamnus Diels）和西固紫菀（A.sikuensis W.W.Smith et Farr.）,新近的分子系统学研究对密毛系是否单系提出质疑。该文采用常规根尖压片法,对紫菀属密毛系3种植物4个居群的核型进行观察分析。结果显示：3种植物的核型公式均为2n=2x=18=14m＋4sm（2SAT）;密毛紫菀居群2个的核型属于1A型,灰枝紫菀和西固紫菀为2A型。密毛紫菀和西固紫菀的核型资料为首次报道。灰枝紫菀的染色体数目、基数和不对称性等核型资料与先前唯一的相关报道结果（体细胞染色体数目为32,核型公式2n=2x=32=26sm＋6st,属4A型,染色体中未发现随体）迥然不同。3种植物的核型结果不支持保留密毛系,而核型不对称性类型支持该实验室先前提出的亚属划分。3种植物随体的大小属于紫菀亚族型,这支持欧亚紫菀属与北美紫菀类没有密切亲缘关系的观点。

英文摘要：

Aster vestitus Franch.,A.poliothamnus Diels and A.sikuensis W.W.Smith et Farr.comprise Aster Series Vestiti Ling （Asteraceae） whose monophyly was not supported by a new molecular phylogenetic investigation.Karyotypes of four populations of the three species were analyzed by conventional root tip squash method.The results showed that all the three species had a karyotypic formula of 2n=2x=18=14m＋4sm（2SAT）,while the two populations of A.vestitus belonged to the Stebbins’ 1A karyotype and the other two species to the Stebbins’ 2A.The karyotypic data of A.vestitus and A.sikuensis were reported for the first time and that of A.poliothamnus was quite different from that reported by the only previous related study.The results did not suggest maintaining Ser.Vestiti but support the comment of Li et al.on subgeneric classification.Satellite size of the three species belonged to “Asterinae type”,which supported the opinion that there is no close relationship between Eurasian Aster and North American asters.