It is closely related to the American beechFagus grandifolia and is usually treated as Fagus grandifolia subsp. mexicana (Martínez) E.Murray.[3][4][5][6]
Fagus mexicana is a deciduoustree, reaching heights of 25–40 m tall and up to 1 m trunk diameter. The leaves are alternate and simple, with a slightly toothed margin, usually smaller than those of American beech, 5–8 cm long and 3–5 cm broad. The buds are long and slender, 15–25 mm long and 2–3 mm thick.
The flowers are small catkins which appear shortly after the leaves in spring. The seeds are small triangular nuts 15–20 mm long and 7–10 mm wide at the base; there are two nuts in each cupule, maturing in the autumn 6–7 months after pollination.
^Williams-Linera, Guadalupe; Devall, Margaret S.; Alvarez-Aquino, Claudia (2000). "A Relict Population of Fagus grandifolia var. mexicana at the Acatlan Volcano, Mexico: Structure, Litterfall, Phenology and Dendroecology". Journal of Biogeography. 27 (6): 1297–1309. doi:10.1046/j.1365-2699.2000.00500.x. JSTOR2656078. S2CID84997258.
^Williams-Linera, Guadalupe; Rowden, Adèle; Newton, Adrian C. (2003). "Distribution and stand characteristics of relict populations of Mexican beech (Fagus grandifolia var. mexicana)". Biological Conservation. 109: 27–36. doi:10.1016/S0006-3207(02)00129-5.
