Abstract: The present paper recognized that according to the morphology comparison autoallopolyploid Sequoia sempervirens with genomic formula AAAABB[3] may originate from the hybridzation between romeone ancient species of Metasequoia and Sequoiadendron which were the parents. Metasequoia glyptostroboides and Sequoiadendron giganteum were direct descendants of the parents probably, which proyided gcnomes AA and B for S. sempervirens res- pectively.The concluson was the same as that based on the karyotypic data[19], but did not agree with Stebbins' inference that another ancestor,except Metasequoia, was extinct and did not left any close relatiyes.

Key words: Sequoia sempervirens

摘要： 本文通过形态性状的比较研究认为AAAABB 的同源异源多倍体红杉可能由亲本水杉（属）和巨杉（属）一杂交起源，它们分别为红杉提供了染色体组AA和染色体组B。这与根据核型等资料的分析结果相吻合。但跟Stebbins认为红杉除水杉（属）以外的另一个亲本已经灭绝并没有留下近缘的推论存在分歧。

关键词: 北美红杉, 形态学, 亲本