Emersed plants are rooted in water-saturated soils or submersed soils near the water’s edge. The leaves and stems grow above the water. During low-water conditions, emersed plants can grow in exposed, damp, sediments.
Some emersed plants are large-leaved, with big spikes of flowers: the arrowheads (Sagittaria spp.) and fire flag (Thalia geniculata). Some are small plants, growing inches above the water (Bacopa spp.). Some are viney, rooted in the mud but crawling across the water: water spinach (Ipomoea aquatica). Some are tall and leafy: the native lake hygrophila (Hygrophila costata). Some can fill a large prairie: bur-marigold (Bidens laevis).
Aquatic grasses, sedges, and rushes are also in the emersed-plant category. Among Florida's native giant grasses are sugarcane plume grass (Saccharum giganteum) and giant foxtail (Setaria magna). Shorter grasses, such as maidencane (Panicum hemitomon) and knotweed (Polygonum spp.), grow in shallow marshes and lake margins and are extremely valuable to Florida's fisheries. Sedges include the dominant plant in the Everglades, sawgrass (Cladium jamaicense), and star-rush (Dichromena spp.). Bulrushes include Scirpus spp. and the true rushes of Florida: soft rush (Juncus effusus).
Unfortunately, Florida has many non-native invasive grasses, sedges, and rushes: torpedograss (Panicum repens), paragrass (Urochloa mutica), napier grass (Pennisetum purpureum), and West Indian marsh grass (Hymenachne amplexicaulis).
Emersed plants occur in all Florida waterbodies within a zone from a few feet to hundreds of feet. The zone changes most often in response to changing water levels. When periods of low water are followed by a rapid rise in water level, large sections of emersed plants may be uprooted. Sustained high water can also reduce emersed-plant abundance. In periods of low water, debris from dying emersed plants is a significant factor. Accumulated plant debris can eventually result in the lake becoming shallower, or even transitioning into a swamp or marsh.
