Abstract The present report is based on a cytological data base on 614 (56.0 %) of the total 1104 recognized species and 82 (90.0 %) of the 88 recognized genera of gymnosperms. Family Cycadaceae and many genera of Zamiaceae show intrageneric uniformity of somatic numbers, the genus Zamia is represented by a range of number from 2n=16-28. Ginkgo, Welwitschia and Gentum show 2n=24, 2n=42, and 2n=44 respectively. Ephedra shows a range of polyploidy from 2x-8x based on n=7. The family Pinaceae as a whole shows 2n=24except for Pseudolarix and Pseudotsuga with 2n=44 and 2n=26 respectively. Araucariaceae constantly shows 2n=26 while Podocarpaceae has a range of 2n=18-38. Sciadopityaceae and Cupressaceae are represented by 2n=20 and 2n=22 respectively. Taxaceae shows variable numbers of 2n=24, 36 and 22. Polyploidy is exceptional being represented by 8.0 % of the taxa studied. B-chromosomes have been studied in 31 taxa while heteromorphic sex chromosomes have been reported in some dioecious taxa.

中文翻译：

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裸子植物中的染色体数 - 更新

摘要 本报告基于对裸子植物 1104 个已识别物种中的 614 个 (56.0%) 和裸子植物 88 个已识别属中的 82 个 (90.0%) 的细胞学数据。苏铁科和杂草科的许多属表现出体细胞数的属内一致性，杂草属由2n=16-28的数字范围表示。Ginkgo、Welwitschia 和 Gentum 分别显示 2n=24、2n=42 和 2n=44。麻黄显示了基于 n=7 的 2x-8x 范围的多倍性。松科作为一个整体显示2n=24，除了Pseudolarix 和Pseudotsuga 分别为2n=44 和2n=26。南洋杉科持续显示 2n=26，而罗汉果科的范围为 2n=18-38。Sciadopityaceae 和Cupressaceae 分别由2n=20 和2n=22 表示。紫杉科显示可变数为 2n=24、36 和 22。多倍体是例外，由 8 表示。0 % 的分类群被研究。已经在 31 个分类群中研究了 B 染色体，而在一些雌雄异株的分类群中报道了异形性染色体。