Biota of Lakes and Reservoirs - Hydro-Environmental Analysis: Freshwater Environments - page 434

parts living for longer than 1 year; LakeWatch 2007) and the emergent macrophytes share many
similarities with terrestrial plants (Wetzel 2001).
Freely loating macrophytes : Freely loating macrophytes are a diverse group of plants, with the
more elaborate plants consisting of aerial or loating leaves, a condensed stem, and submersed roots
(Wetzel 2001). They can be very large, such as the water hyacinth or water lettuce, or very small sur-
face-loating plants with few or no roots (e.g., duckweed). These plants generally grow in portions
of lakes that are not subject to periodic drying, and in areas where currents are slow. Dense mats or
stands may form, often for many species from spreading underground rhizomes (LakeWatch 2007),
which often pose a problem for their control (Figure 15.23).
Submerged macrophytes: Submerged macrophytes are also a diverse group of plants that have
submerged leaves, examples of which are illustrated in Figure 15.24. They are commonly rooted

Pond lilies

Duckweed and watermeal

FIGURE 15.23 Examples of free-loating macrophytes. (From Ohio Pond Management Plant Identiication,
Ohio Department of Natural Resources.)

Water milfoil

Najas

Chara

Coontail

Elodea

FIGURE 15.24 Examples of submerged macrophytes. (From Ohio Pond Management Plant Identiication,
Ohio Department of Natural Resources.)