Fagaceae Barthélemy Charles Joseph Dumortier, 1829.
Fagaceae: Deciduous or evergreen trees or shrubs. Leaves alternate, simple subentire to lobed, stipules often caducous. Flowers unisexual, apetalous, monoecious, usually in different inflorescences (except Castanea). Male flowers in catkins or long stalked heads; perianth 4-6(-7) lobed, stamens usually twice as many as perianth segments, pistillode sometimes present. Female flowers borne singly or in threes, arranged in spikes or at base of male inflorescence, each flower or group of 3 with a basal scaly involucre; perianth 4-6 lobed, epigynous, ovary inferior, 3 or 6 celled; ovules 2 per cell, axile; styles 3 or 6. Fruit a 1 seeded nut, 1-3 nuts being surrounded by a scaly or spiny cupule formed from accrescent involucre.
1. Buds fusiform; male flowers in long stalked pendent heads, nuts triangular ovoid 1. Fagus
1. Buds ovoid, male flowers in erect or pendent catkins, nuts oblong, cylindrical, subglobose or ovoid, not triquetrous
2. Cupule completely enclosing nuts, flowers in erect catkins, upper part male, lower part female 2. Castanea
2. Cupule enclosing lower half of nut, male flowers in pendent catkins, male and female flowers in separate inflorescences 3. Quercus