Site differences in the clone structure of an emergent sedge, Cladium jamaicense

While a great deal is known about seral variation in clonal growth patterns of plants, little is known about variation in the clonal growth of mature populations growing in different habitats. In this study, clone size (maximum radius) and clone structure (numbers and locations of live and dead culms within clones) were examined in an emergent sedge, sawgrass (Cladium jamaicense Crantz), at three different wetland sites within Everglades National Park. One population was a productive, nearly pure stand of recently burned sawgrass growing in deep hydric pear. The other two populations were located within a less productive seasonally flooded marl prairie in the interior of the park mixed with other species, Most of the variables related to clone size (e.g. clone radius, mean and median rhizome length, rhizomes per clone) did not differ significantly among sites. There were significant differences in the proportion of culms that were alive among sites. The proportion of culms that were alive was greatest at the pure-stand pear sie and lowest at the unburned marl site, The size and relative location of live and dead culms within clones suggested that either higher rates of culm mortality or lower,growth rates of culms resulted in live culms being restricted to more peripheral parts of clones at the marl prairie sites than at the pure-stand peat site. These data suggest that the site differences in the productivity of a mature stand of sawgrass are associated with differences in patterns of clonal growth.