vernal pools of California. Their vegetation is dependent upon the ^ 



season and the duration of flooding. The herbaceous vegetation of ex- ^ 



posed open sites (F-l-M) includes smartweeds (Polygonum spp.), fall O 



panicum (Panicum dichotomiflorum), tealgrass (Eragrostis hypnoides), ^ 



and wild millet (Echinochloa crusgalli). Vernal pools exhibit a unique 

 flora, individual species of which change form from truly aquatic to > 



spiny xerophytic as site conditions become more xeric. Bottomland q 



forests along rivers (F-l-Sw) may be composed of cottonwood w 



(Populus deltoides), silver maple (Acer saccharinum), black willow 

 (Salix nigra), elm {Ulmus spp.) in the Northeast and Midwest; gums 

 (Nyssa spp.), oaks (Quercus spp.), sweet gum (Liquidambar styraciflua), 

 and cypress (Taxodium distichum) in the South and Southeast. 



FRESH MEADOWS (F-2-M). The water table is at or near the sur- 

 face, but usually there is no standing water. Such sites often exhibit a 

 rich floristic diversity, including grasses, sedges, rushes, and colorful, 

 broad-leaved, flowering plants. They are especially abundant in the 

 Fake States and Florida. They also include the spring- and snow-fed al- 

 pine meadows, beaver meadows, and cienegas. The vegetation is domi- 

 nantly herbaceous and includes such plants as the manna grasses 

 (Glyceria spp.), canary grass (P/ialaris arundinacea) , tealgrass 

 (Eragrostis hypnoides), prairie cordgrass (Spartina pectinata), sedges 

 (Care.x spp.), rushes (Juncus spp.). In the South cordgrasses {Spartina), 

 paspalums (Paspalum spp.), and beakrushes ( Rhynochospora spp.) are 

 common. 



SHALLOW FRESH MARSHES (F-3-M). The soil is waterlogged 

 throughout the vegetative season, and the sites are often covered with 

 6 inches or more of water. They occur throughout the United States as 

 shallow basins and sloughs and along the margins of shallow lakes or 

 the borders of deep marshes. The vegetation is dominated primarily by 

 emergent aquatic plants such as cattails (Typha spp.), arrowheads 

 (Sagittaria spp.), burreed (Sparganium spp.), pickerelweed (Pontederia 



cordata), bulrushes (Scirpus spp.), galingale (Cyperus spp.), smart- 

 weeds {Polygonum spp.), spikerushes (Eleocharis spp.). rushes (Juncus 

 spp.), vvhitetop grass (Scolochloa festucacea) , rice cutgrass (Leersia ory- 

 zoides), and reed (Phragmites communis). Others especially common in the 

 Southeast, including the Everglades, are maidencane (Panicum nemitomon) 

 and sawgrass (Claudium jamaicense). 



DEEP FRESH MARSHES (F-4-M). The water depth may range 

 from 6 inches to 3 ft during the growing season. These areas include 

 shallow lakes, sloughs, potholes, limestone sinks, and margins of open- 

 water areas. This distribution is widespread, but concentrated in the 

 north-central United States and Florida. The vegetation of the more 

 shallow water phase includes the emergents previously listed (F-3-M). 

 The deeper water supports floating plants such as water lilies (Nuphar 

 spp., Castalia spp.) and duckweeds (Lemna spp.), and submerged 

 aquatics such as pondweeds (Potamogeton spp.), water weeds 



