National Herbarium, Pakistan Agricultural Research Council, Islamabad.
Trees or large shrubs, monoecious or polygamous. Leaves simple, alternate. stipulate, usually with oblique bases, petiolate. Flowers small, bisexual or unisexual. solitary, cymose or in axillary fasciculate clusters. Perianth 4-8, campanulate, persistent. Stamens as many as and opposite the perianth lobes or fewer. Ovary superior, unilocular with solitary ovule; styles 2, linear, stigmatose along inner surface. Fruit a drupe or a broadly winged samara.
A family of 15 genera and c. 200 species distributed in tropical and temperate regions of the northern hemisphere. Represented in Pakistan by 3 genera and 7 species.
Acknowledgements: We are grateful to the U.S. Department of Agriculture for financing this research under PL-480. Thanks are also due to Mr. I.C. Hedge, Royal Botanic Garden, Edinburgh, for going through the manuscript.