Our only development of coastal marshlands occur on the Gulf Coast of Texas. 

 The area is characterized not only by salt meadows, salt marshes, tidal flats and 

 estuaries, but also by fresh-water marshes, swamps, meandering bayous and 

 resacas, and sloughs. Some of the nation's largest wild-life reservations, especially 

 for waterfowl, are to be found in this region. 



The salt marsh areas typically support species of Carex, Cyperus, Eleocharis, 

 Rhynchospora, Scirpus, several cordgrasses (Spartina) and seashore saltgrass 

 (Distichlis spicata) . 



Aquatic plants abound in this region. Among these are Wolffia, Wolffiella 

 lingulata, parrot's feather (Myriophyllum), pondweeds (Potamogeton), duck- 

 weeds (Lemna), duck meat (Spiroclela), water-lilies (Nymphaea), cow-lily 

 {Nuphar luteum) , Hygrophila lacustris and arrowheads {Sagittaria) . The bene- 

 ficial aquatic plant species as well as open water for fish and wildlife in many of 

 the streams, canals, lakes and ponds are threatened by several introduced noxious, 

 aggressive species. Foremost among these are the water hyacinth (Eichhornia 

 crassipes) and alligator weed {Alterncmthera philoxeroides) . The native cat-tails 

 (Typha) also belong here. Other species that can and may prove to be trouble- 

 some in this and other parts of our region are aquatic species of water-primrose 

 (Ludwigia), water-lettuce (Pistia Stratiotes), common frogbit {Limnobium 

 Spongia) and American featherfoil {Hottonia inflata). In bays and open waters 

 along the Gulf Coast are to be found such marine species as Cymodocea filiformis, 

 Thalassia testiidinum, Halophila Engelmannii, Halodiile Beaudettei, and rarely 

 Posidonia Oceania. Some of these are often washed up on the beaches along the 

 coast. 



Shallow ponds and backwaters of river margins are usually the beginnings of 

 fresh-water marshes. These marshlands are treeless expanses, often with dense 

 growths of herbaceous plants such at cat-tails, grasses and sedges. In marsh pools, 

 where the water is deeper, water lilies, pondweeds and other plants become estab- 

 lished. 



Plants such as cat-tails, bulrushes, bur-reeds, Sagittarias, Pickerelweed. Peltandra 

 and button-bush are rooted in mud in shallow water on the edge of ponds and 

 quiet backwaters of rivers. In ponds, for instance, plants grow outward from the 

 bank and shallow water to deeper water where water-lilies, Nuphar and Brasenia 

 take their place. On out into the deepest open waters both rooted and free-floating 

 plants such as the carnivorous bladderworts, pondweeds, Cahomba and Cerato- 

 phyllum are found. Through the years as the plants on the outer periphery con- 

 tinue to move toward the center of the pond they shade and crowd out the floating 

 and submerged plants that die and contribute to the filling of the pond. As the 

 filling continues the vegetative composition of the pond is affected until a marsh 

 is evolved — a treeless tract of water and aquatic plants. 



With continued filling by dead plants and silt the marsh, in turn, will give way 

 to the sedge-filled meadow that, with the invasion of trees and shrubs, will even- 

 tually become a wooded swamp. 



Littoral vegetation zones similar to those found in lakes are often found along 

 streaYns, especially if shallow water areas occur. Pickerel weed {Pontederia 

 cordata). smartweed (Polygonum) and various grasses and sedges are often to be 

 found in such areas. 



Similarly to our lack of glaciation-formcd lakes, our region does not have 

 the type of bogs that are characteristic of far northern glaciated regions. Some 

 of the bogs developed in the high mountains of New Mexico and Arizona 

 approach these northern bogs, but they lack most of their characteristics. In 

 glaciated country, lakes formed by ice often have relatively steep banks and poor 

 drainage that make them conducive for the formation of bogs. True bogs are 

 characterized by having low-growing shrubs and sedges in sphagnum mosses. 



