Homalolepis was described by Turczaninow in 1848 and reestablished by Devecchi et al. in 2018, enclosing mostly the extra-Amazonian species previously included in two sections of Simaba Aubl.. We performed the first cytogenetic analysis in Homalolepis and, by surveying chromosome numbers of other Simaroubaceae representatives, reconstructed the evolution of chromosome numbers in the family, using ChromEvol software. The four Homalolepis species showed 2n = 32 and two or four CMA⁺ bands. In situ hybridization showed a diverse distribution of ribosomal DNA sites (5S and 18S), positioned on the same chromosome pair in H. floribunda (A. St.-Hil.) Devecchi & Pirani or on different chromosome pairs in H. arenaria (Devecchi & Pirani) Devecchi & Pirani. The basic chromosome number here indicated for Simaroubaceae is x = 12, from which chromosome numbers of other genera were derived by ascending dysploidy, with polyploidy occurring in Ailanthus Desf. only. Homalolepis presents x = 16, derived by ascending disploidy.

Homalolepis由 Turczaninow 于 1848 年描述，并由 Devecchi 等人重新建立。在 2018 年，主要包括之前包含在Simaba Aubl两个部分的亚马逊外物种。我们在Homalolepis 中进行了第一次细胞遗传学分析，并通过调查其他 Simaroubaceae 代表的染色体数，重建了该科中染色体数的进化，使用ChromEvol 软件。四个Homalolepis物种显示 2 n  = 32 和两个或四个 CMA ⁺条带。原位杂交显示核糖体 DNA 位点（5S 和 18S）的不同分布，位于H. floribunda的同一染色体对上(A. St.-Hil.) Devecchi & Pirani 或在H. arenaria (Devecchi & Pirani) Devecchi & Pirani 中的不同染色体对上。此处指出的苦木科的基本染色体数为x  = 12，其他属的染色体数由上升的异常倍体衍生而来，多倍体出现在臭椿Desf。只要。Homalolepis呈现x  = 16，由升序二倍体衍生而来。