Botany Department, Gordon College, Rawalpindi.
Usually monoecious, deciduous or evergreen trees or shrubs. Leaves simple, alternate; stipules present, soon deciduous. Perianth of 4-7(-8-9) tepals. Male flowers on slender catkins or spikes, solitary or in groups; stamens 5 or more; pistillode sometimes present. Female flowers solitary or in groups of 3; staminodes usually present; carpels 3, usually united; ovary inferior with 2 pendulous ovules in each locule; styles 3 or more. Fruit a nut (acorn), surrounded by a cup-like structure, the cupule.
A family of 8 genera and c. 900 species found in the temperate regions of the new and the old worlds. Represented here by 2 genera and 7 species.
Acknowledgement: We are grateful to the U.S. Department of Agriculture for financing this research under PL-480. Thanks are also due to Messrs. B.L. Burtt, I.C. Hedge and Miss J. Lamond of the Royal Botanic Garden, Edinburgh, for going through the manuscript and giving valuable suggestions.