20 



pioneer plants which become established during periods 

 of low water are not Emergent Wetlands and should be 

 classified as Vegetated Unconsolidated Shores or Vege- 

 tated Streambeds. 



Subclasses and Dominance Types. 

 Persistent.— Persistent Emergent Wetlands are domi- 

 nated by species that normally remain standing at least 

 until the beginning of the next growing season. This 

 Subclass is found only in the Estuarine and Palustrine 

 Systems. 



Persistent Emergent Wetlands dominated by saltmarsh 

 cordgrass (Spartina alterniflora), saltmeadow cordgrass 

 (S. patens), big cordgrass (S. cynosuroides), needlerush 

 (Juncus roemerianus), narrow-leaved cattail (Typha 

 angustifolia), and southern wild rice (Zizaniopsis miliacea) 

 are major components of the Estuarine systems of the 

 Atlantic and Gulf Coasts of the United States. On the 

 Pacific Coast, common pickleweed (Salicornia virginica), 

 sea blite (Suaeda californica), arrow grass (Triglochin 

 maritimum), and California cordgrass (Spartina foliosa) 

 are common dominants. 



Palustrine Persistent Emergent Wetlands contain a vast 

 array of grasslike plants such as cattails (Typha spp.), 

 bulrushes (Scirpus spp.), saw grass (Cladium jamaicense), 

 sedges (Carex spp.); and true grasses such as reed 

 (Phragmites australis), manna grasses (Glyceria spp.), 

 slough grass (Beckmannia syzigachne), and whitetop 

 (Scolochloa festucacea). There is also a variety of broad- 

 leaved persistent emergents such as purple loosestrife 

 (Lythrum salicaria), dock (Rumex mexicanus), water- 

 willow (Decodon verticillatus), and many species of smart- 

 weeds (Polygonum). 



Nonpersistent— Wetlands in this Subclass are domi- 

 nated by plants which fall to the surface of the substrate 

 or below the surface of the water at the end of the grow- 

 ing season so that, at certain seasons of the year, there 

 is no obvious sign of emergent vegetation. For example, 

 wild rice (Zizania aquatica) does not become apparent in 

 the North Central States until midsummer and fall, when 

 it may form dense emergent stands. Nonpersistent emer- 

 gents also include species such as arrow arum (Peltandra 

 virginica), pickerelweed (Pontederia cordata), and arrow- 

 heads (Sagittaria spp.). Movement of ice in Estuarine, 

 Riverine, or Lacustrine Systems often removes all traces 

 of emergent vegetation during the winter. Where this 

 occurs, the area should be classified as Nonpersistent 

 Emergent Wetland. 



Scrub-Shrub Wetland 



Definition. The Class Scrub-Shrub Wetland includes 

 areas dominated by woody vegetation less than 6 m 

 (20 feet) tall. The species include true shrubs, young trees, 

 and trees or shrubs that are small or stunted because of 

 environmental conditions. All water regimes except sub- 

 tidal are included. 



Description. Scrub-Shrub Wetlands may represent a 

 successional stage leading to Forested Wetland, or they 

 may be relatively stable communities. They occur only in 

 the Estuarine and Palustrine Systems, but are one of the 

 most widespread classes in the United States (Shaw and 

 Fredine 1956). Scrub-Shrub Wetlands are known by many 

 names, such as shrub swamp (Shaw and Fredine 1956), 

 shrub carr (Curtis 1959), bog (Heinselman 1970), and poco- 

 sin (Kologiski 1977). For practical reasons we have also 

 included forests composed of young trees less than 6 m 

 tall. 



Subclasses and Dominance Types. 



Broad-leaved Deciduous.— In Estuarine System Wet- 

 lands the predominant deciduous and broad-leaved trees 

 or shrubs are plants such as sea-myrtle (Baccharis halimi- 

 folia) and marsh elder (Ivafrutescens). In the Palustrine 

 System typical Dominance Types are alders (Alnus spp.), 

 willows (Salix spp.), buttonbush (Cephalanthus occiden- 

 tal), red osier dogwood (Cornus stolonifera), honeycup 

 (Zenobia pulverulenta), spirea (Spiraea douglasii), bog 

 birch (Betula pumila), and young trees of species such as 

 red maple (Acer rubrum) or black spruce (Picea mariana). 



Needle-leaved Deciduous.— This Subclass, consisting 

 of wetlands where trees or shrubs are predominantly 

 deciduous and needle-leaved, is represented by young or 

 stunted trees such as tamarack or bald cypress (Taxodium 

 distichum). 



Broad-leaved Evergreen.— In the Estuarine System, 

 vast wetland acreages are dominated by mangroves 

 (Rhizophora mangle, Languncularia racemosa, Conocar- 

 pus erectus, and Avicennia germinans) that are less than 

 6 m tall. In the Palustrine System, the broad-leaved ever- 

 green species are typically found on organic soils. North- 

 ern representatives are labrador tea (Ledum groenlan- 

 dicum), bog rosemary (Andromeda glaucophylla), bog 

 laurel (Kalmia polifolia), and the semi-evergreen leather- 

 leaf (Chamaedaphne calyculata). In the south, fetterbush 

 (Lyonia lucida), coastal sweetbells (Leucothoe axillaris), 

 inkberry (Ilex glabra), and the semi-evergreen black ti-ti 

 (Cyrilla racemiflora) are characteristic broad-leaved 

 evergreen species. 



Needle-leaved Evergreen.— The dominant species in 

 Needle-leaved Evergreen Wetlands are young or stunted 

 trees such as black spruce or pond pine (Pinus serotina). 



Dead.— Dead woody plants less than 6 m tall dominate 

 Dead Scrub-Shrub Wetlands. These wetlands are usual- 

 ly produced by a prolonged rise in the water table resulting 

 from impoundment of water by landslides, man, or 

 beavers. Such wetlands may also result from various other 

 factors such as fire, salt spray, insect infestation, air pollu- 

 tion, and herbicides. 



Forested Wetland 



Definition. The Class Forested Wetland is characterized 

 by woody vegetation that is 6 m tall or taller. All water 

 regimes are included except subtidal. 



