Fagus mexicana 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. Fagus mexicana Fagus mexicana, the Mexican beech or haya, is a species of beech endemic to northeastern and central Mexico, where it occurs from southwest Tamaulipas south to Hidalgo and Puebla. It is restricted
Stigmella hemargyrella Stigmella hemargyrella Stigmella hemargyrella is a moth of the Nepticulidae family. It is found in most of Europe, except Iceland, Norway, Finland, Portugal and most of the Baltic region. The moths (imago) are bivoltine flying from April to May and again from July to August and can be found resting on trunks. The wingspan is 5–6 mm. The egg can be laid on either side of the leaf and the pale yellowish-white larva feed, within a mine on "Fagus sylvatica" and "Fagus sylvatica orientalis". The mine is a sinuous gallery and at the early state is relatively narrow with a