GHULAM RASOOL SARWAR
Department of Botany, University of Karachi,
Annual or perennial, submerged, floating or rarely terrestrial plants. Stems elongated when submerged, contracted when emersed. Leaves exstipulate, opposite, often crowded in rosette above, glabrous, linear, elliptic, oblong, spathulate, entire, usually with a forked apex. Flowers minute, unisexual, solitary or rarely 1 male and 1 female in the same leaf axil, with 2 opposite scarious bracts, rarely ebracteate, calyx and corolla absent; male flowers bearing single stamen, anther 4-locular, later becoming 2-locular, finally 14ocular at anthesis, reniform; female flowers bearing 1 pistil with 4-locular ovary (at first 2-locular, later becoming 4-locular with the development of pseudoseptum); styles 2, frliform; fruit dry, 4-lobed, at maturity splitting into 4, 1-seeded mericarps.
A family of single genus and 17 species, almost cosmopolitan in distribution. Represented in Pakistan by 2 species.
Acknowledgements: We are grateful to the authorities of BM, K, RAW for providing herbarium and library facilities and for the loan of specimens and to Prof. C.DK. Cook (Zurich) for going through the manuscript and offering valuable suggestions.