National Herbarium, Agricultural Research Council,
Herbs. Leaves simple or compound, alternate, rarely opposite, usually exstipulate. Inflorescence cymose or racemose, rarely flowers solitary. Flowers 4-5-merous; bisexual or occasionally unisexual. Calyx free or adnate to the ovary, imbricate or valvate. Petals free, sometimes absent. Stamens twice or equal to the number of sepals. Carpels 2(-4), free or united at the base; ovary 1-2-locular; superior, inferior or semi-inferior; placentation axile; styles 2, or as many as the carpels. Fruit a capsule; seeds many.
Hydrangeaceae,Parnassiaceae.Philadelphiaceae and Grossulariaceae were previously often included in Saxifragaceae but are now generally placed as independent families (as in this Flora) because of habit, vegetative and floral differences.
A family of c. 30 genera and c. 580 species mostly distributed in the cold and temperate regions. Represented here by 3 genera.
Acknowledgements: We are grateful to the United States 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 their helpful suggestions and to the Directors Herbarium, Royal Botanic Gardens, Kew and Herbarium Royal Botanic Garden, Edinburgh, for the loan of material.