Mexican beech [Fagus grandifolia subsp. mexicana (Martinez) A.E.Murray] is a subspecies endemic to the Sierra Madre Oriental Mountains and considered endangered due to the low density of its populations and high degree of habitat fragmentation and environmental specificity. Because its morphological and genetic variation is associated with its ability to adapt to changes in environmental conditions, the objective of this study was to determine whether phenotypic and genotypic variation exist, and it relationships with population reduction events. In four beech populations in the states of Hidalgo and Veracruz, we analyzed 11 morphological variables for leaves and 6 microsatellite markers. The morphological variables that to discriminate between populations were related to the size of the leaf, but a robust differentiation pattern was not found, given that independent groups of leaves were identified. The populations located closest to each other, had greater genetic variation and less genetic distance; populations in the extreme north and south had the lowest genetic variation. Genetic differentiation among populations was associated with reduction in population size. In the 3 localities in Hidalgo, recent bottlenecks were identified, and in Veracruz, an old bottleneck was found. Variation in leaf morphology and genetic structure of Mexican beech populations could be the result of a combination of various geographical, climate and ecological factors.

墨西哥山毛榉 [ Fagus grandifolia subsp. 墨西哥(Martinez) AEMurray] 是马德雷山脉东方山脉特有的一个亚种，由于其种群密度低、栖息地高度破碎化和环境特殊性，被认为是濒危物种。由于其形态和遗传变异与其适应环境条件变化的能力有关，因此本研究的目的是确定是否存在表型和基因型变异，以及它与种群减少事件的关系。在伊达尔戈州和韦拉克鲁斯州的四个山毛榉种群中，我们分析了 11 个叶片形态变量和 6 个微卫星标记。区分种群的形态变量与叶的大小有关，但没有发现强大的分化模式，鉴于确定了独立的叶子组。距离最近的种群，遗传变异较大，遗传距离较小；极北和极南的种群遗传变异最低。种群间的遗传分化与种群规模的减少有关。在伊达尔戈的 3 个地方，发现了最近的瓶颈，在韦拉克鲁斯，发现了一个旧的瓶颈。墨西哥山毛榉种群叶片形态和遗传结构的变化可能是各种地理、气候和生态因素综合作用的结果。种群间的遗传分化与种群规模的减少有关。在伊达尔戈的 3 个地方，发现了最近的瓶颈，在韦拉克鲁斯，发现了一个旧的瓶颈。墨西哥山毛榉种群叶片形态和遗传结构的变化可能是各种地理、气候和生态因素综合作用的结果。种群间的遗传分化与种群规模的减少有关。在伊达尔戈的 3 个地方，发现了最近的瓶颈，在韦拉克鲁斯，发现了一个旧的瓶颈。墨西哥山毛榉种群叶片形态和遗传结构的变化可能是各种地理、气候和生态因素综合作用的结果。