Trees or shrubs with opposite, exstipulate and palmate compound leaves. Inflorescence a polygamous terminal panicle, the upper flowers male. Flowers with jointed pedicels. Calyx of 5 united sepals. Petals 4-5, irregular. Disc unilateral, present outside the stamens. Stamens 5-9, free. Gynoecium tricarpellary, syncarpous; ovary 3-locular, with 2 ovules in each locule. Fruit a loculicidal capsule, dehiscing by 3 valves. Seeds few, large.
A family of 2 genera and 15 species distributed in temperate N. and S. America, Europe, S. and E. Asia. Represented here by 1 genus.
Acknowledgements: We are grateful to the U.S. Department of Agriculture for financing this research under P.L. 480. Thanks are also due to Messrs. B.L. Burtt, I.C. Hedge and Miss J. Lamond of the Royal Botanic Garden, Edinburgh, for their helpful suggestions.