VERSATILE MODES OF PROPAGATION IN CLADIUM JAMAICENSE IN THE FLORIDA EVERGLADES

The Florida Everglades is a subtropical wetland dominated by Cladium j amaicense (sawgrass), a native sedge that forms extensive, monospecifi c stands. Sawgrass exhibits several modes of reproduction, including s exual (seed production) and asexual (rhizome propagation) types. In th is study, the occurrence of vegetative proliferation on the reproducti ve organs of sawgrass, a phenomenon otherwise known in arctic-alpine h abitats, was observed. This is the first time that vegetative prolifer ation has been reported in Cladium. Vegetative plantlets developed in the spikelets of the inflorescence but also commonly at the lower node s on the inflorescence. The number of plantlets per inflorescence rang ed from 400 to 4000. The plantlets differed in size from a few leaves to eight to ten leaves of up to 70 mm in length. Although the nutrient concentration of the seeds were greater than those of the plantlets, the total content of P, N and C of the plantlets was twice that of the seeds owing to the greater weight of the plantlets. In spikes with ve getative proliferation, the leafy shoot developed beside the ovary, an d seed formation did not occur. Usually, only one plantlet developed i n each flower, although more buds did form occasionally within a singl e flower. The simultaneous occurrence of diverse modes of propagation in sawgrass populations may be an adaptation to typical Everglades hab itats with extreme interannual wet-dry cycles. (C) 1998 Annals of Bota ny Company.