A mortality of saw-grass (Cladium jamaicense) and other plants occurred between 1957 and 1961 in southwestern Louisiana involving 162,000 ha.of marsh. Flooding and high salinities associated with Hurricane Audrey (June 1957) and subsequent droughts are blamed. Plant succession in an area affected by the die-off was studied by line-intercept transects on the Lacassine National Wildlife Refuge from 1958 through 1974. In 1958, 86 percent of the area sampled by the transect lines was open water while only 2 percent was open water in 1974. In 1974, bulltongue (Sagittaria lancifolia) occupied 71 percent of the transects and. white waterlily (Nymphaea odorata) 12 percent. Alligatorweed (Alternanthera philoxeroides), spikerushes (Eleocharis spp.), floating heart (Nymphoides aquatica), bvuttonbush (Cephalanthus occidentalis), and willow (Salix nigra) were common associates ranked in order of abundance. During spring droughts (1960-1965) annual grasses and sedges were abundant. The die-off of sawgrass and the subsequent plant succession affected populations, distribution, and food habits of wintering waterfowl in southwestem Louisiana.