Perennial or annual, terrestrial or epiphytic usually rhizomatous herbs. Roots fibrous or tuber-like. Usually rhizome present. Leaves spiral, opposite or whorled on the aerial stem or in basal rosettes; sessile or ± petiolate, with or without sheathing base, lamina entire, ovate to linear, rarely sagittate, with few prominent parallel veins. Inflorescence racemes or spikes or borne in axillary clusters on a leafy stem. Flowers bisexual, actinomorphic, hypogynous or epigynous. Tepals usually 3 + 3, commonly all similar, gamophyllous, tubular below, lobes free.. Stamens usually 6, filaments free or epiphyllous, commonly inserted in the upper part of the tube; anthers basifixed or dorsifixed, dehiscence longitudinal. Pistil tricarpellary, syncarpous, usually trilocular, placentation axile or basal, ovule 2-many per locule, style simple, stigma capitate or 3-lobed. Fruit usually a berry or capsule rupturing irregularly. Seeds sometimes with a showy sarcotesta.
Seventeen genera and c. 130 spp., distributed in North and Central America, Europe, Russia, Turkey, Afghanistan, Pakistan, India, China and south to about Bali and Lombok and Australia; represented in Pakistan by one genus and four species.
Acknowledgement: We are grateful to the Directors/ Curators of the following herbaria for herbarium and library facilities and for sending the specimens on loan: BM, K, RAW. Special thanks are due to Chris Brickell for going through the manuscript and offering valuable suggestions. We gratefully acknowledge financial support for this publication from the Andrew Mellon Foundation and National Science Foundation (DEB 0103783), Washington, U.S.A. obtained through the Missouri Botanical Garden, St. Louis, U.S.A. We are grateful to Professor Peter H. Raven of the Missouri Botanical Garden for his assistance in securing the support. Grateful thanks are due to Professor Pirzada Qasim Raza Siddiqui, Vice-Chancellor, University of Karachi and Professor Shahid Shaukat, Chairman, Department of Botany, University of Karachi for providing working facilities to the project and for their understanding and encouragement.
This issue is funded in part by the US National Science Foundation and the Andrew W. Mellon Foundation.