Philadelphaceae
MOHAMMAD AMIN SIDDIQI
Stewart Herbarium, Gordon College, Rawalpindi.
Trees, shrubs or undershrubs. Branches often opposite, stellate hairy. Leaves exstipulate, deciduous, simple, opposite or verticillate with pellucid lines or stellate hairs, serrate or entire. Flowers usually in terminal cymes or racemes, rarely solitary or axillary, regular, bisexual. Sepals 5-4, valvate, imbricate or contorted; hypanthium adnate to the base throughout the ovary or up to the top of the ovary. Petals 5-7, valvate, imbricate or connate. Stamens numerous to 4; filaments broadly winged, usually free, sometimes connate at the base. Fruit a septicidal or a loculicidal capsule, rarely a berry. Seeds small, with fleshy endosperm.
A subtropical family of 7 genera and 135 species found from S. Europe to E. Asia, the Philippines, New Guinea, N. & C. America. Represented by only 1 genus and 2 species in W. Pakistan. It was previously included in Saxifrag¬aceae, but in most recent treatments it is separated on the basis of its arboreal habit and the arrangement of leaves. The genera now included in Saxifragaceae are exclusively low herbs with a rosette of basal or alternate leaves, whereas in Philadelphaceae the plants are always woody and the leaves are opposite or verticillate. It is also closely related to Hydrangeaceae from which it can be distinguished by the presence of stellate indumentum and the characteristi¬cally broad winged filaments.
Acknowledgements: We are grateful to the United States Department of Agricultural for financing this research under P.L. 480. Thanks are also due to Messrs B.L. Burtt, I. Hedge and Miss J. Lamond of the Royal Botanic Garden, Edinburgh, for their helpful suggestions.
