Flowering, fruiting and seed germination of the seagrass Cymodocea nodosa (Ucria) Ascherson are recurrent in the Mar Menor coastal lagoon and other places on the southeast Mediterranean coast of Spain, Flowers showed a clumped pattern of spatial distribution (P<0.01) and their density values ranged between 4.7 and 44.8 flowers m(-2). No spatial association was found between male and female flowers (P<0.01) at the spatial scale considered (2500 cm(2)). Seed banks ranged between 0 and 220.3 seeds m(-2), and the seeds showed also a clumped spatial distribution (P<0.01). The vegetative development of some low-density meadows originating from seeds and the effect of water movement on the fate of seed production are discussed.