Hydrangeaceae
MOHAMMAD AMIN SIDDIQI
Stewart Herbarium, Gordon College, Rawalpindi.
Small trees or shrubs, sometimes climbers. Leaves exstipulate, simple, opposite, rarely alternate, glabrous or with simple hairs. Inflorescence corymbose or paniculate cymose; flowers usually perfect and regular, sometimes marginal ones sterile with enlarged sepals. Flowers small, regular, 4-5-merous, perigynous or epigynous, hypanthium somewhat adnate to the lower part of the ovary. Stamens 5 to many, slender. Pistil 2-5-carpellary, ovary semi-inferior or inferior, 2-5-locular; styles free, rarely united. Fruit a loculicidal capsule, rarely a berry. Seeds endospermic.
A north temperate or subtropical family including 10 genera and about 115 species, found mainly in N. America and E. Asia, some of the members being ornamental. Closely related to Philadelphaceae from which it differs by the absence of stellate indumentum and the filaments which are slender and not toothed at the apex.
Acknowledgement: We are grateful to the United States Department of Agriculture for financing this research under P.L. 480.
