分析了北美乔柏（Ｔｈｕｊａｐｌｉｃａｔａ）、北美香柏（Ｔ．ｏｃｃｉｄｅｎｔａｌｉｓ）和西方翠柏（Ｃａｌｏｃｅｄｒｕｓｄｅｃｕｒｒｅｎｓ）的核型，它们的核型公式分别为Ｋ（２ｎ）＝２２＝１６ｍ＝６ｓｍ（２ＳＡＴ），２０ｍ（２ＳＡＴ）＋２ｓｍ和２０ｍ（２ＳＡＴ）＋２ｓｍ。北美乔柏的核型为首次报道。经对侧柏亚科１０个属（２２种）的核型的比较分析，似见南半球５属（Ｃａｌｉｔｒｉｓ，Ａｃｔｉｎｏｓｔｒｏｂｕｓ，Ｌｉｂｏｃｅｄｒｕｓ，Ｍｉｃｒｏｂｉｏｔａ，Ｗｉｄｄｒｉｎｇｔｏｎｉａ）和侧柏属（Ｐｌａｔｙｃｌａｄｕｓ）及Ｔｅｔｒａｃｌｉｎｉｓ最为原始，罗汉柏属（Ｔｈｕｊｏｐｓｉｓ）和崖柏属（Ｔｈｕｊａ）最进化，翠柏属（Ｃａｌｏｃｅｄｒｕｓ）居中。本文还讨论了翠柏属、侧柏属及南半球属的分类位置 The karyotypes of Thujaplicata, T. occidentalis and Calocedrus decurrens in North America were analyzed. Their karyotypes were K (2n) = 22 = 16m = 6sm (2SAT) , 20m (2SAT) + 2sm and 20m (2SAT) + 2sm. North American Qubo karyotype was first reported. A comparative analysis of the karyotypes of 10 genera (22 species) of the Arborvitae showed that the most primitive genera of Calitris, Actinostrobus, Libocedrus, Microbiota, Widdringtonia and Platycladus and Tetraclinis, Thujopsis and Thuja most evolved, and Calocedrus centered. This article also discusses the classification of Cumbria, Platycladus and Southern Hemisphere