Effects of Water Depth on Typha Latifolia and Typha Domingensis

The two species of Typha common in the southeastern United States, T. latifolia and T. domingensis differ substantially in their tolerance to deep water. The objective of this study was to examine the morphology and biomass allocation of these two species to determine if they have similar phenotypic responses to water depth. Replicate monocultures of the two species were established at a range of water depths in an artificial pond and allowed to grow for three growing seasons. At the end of the experiment, subsamples were harvested for determination of plant morphology as well as above‐ and belowground biomass. Both species of Typha showed increases in maximum height with increasing depth. The species less tolerant to deep water ( T. latifolia ) allocated more of its biomass to leaves with increasing water depth. In contrast, the deep water species ( T. domingensis ) showed increased total size of each ramet but a fixed percentage of biomass in leaves with increasing water depth. Both species had a decreasing incidence of flowering and decreasing shoot density with increasing water depth. In general, these species conform to expectations based on considerations of how their carbon budgets would be affected by water depth.