CHAPTER 3. MARSH FLORAS 



3.1 HIGHER PLANTS 



The salt marsh we are concerned with 

 here is almost a monoculture of Spartina 

 alternif lora . Since this plant so 

 dominates the appearance and structure of 

 the marsh, we will spend considerable 

 space discussing what is known of its 

 ecology. Any environmental change that 

 affects the abundance and distribution of 

 S. alterniflora will have a corresponding 

 effect on the salt marsh. 



underground parts. Unlike freshwater 

 wetland plants, it also has a mechanism 

 for dealing with salts and the consequent 

 high osmotic concentration in the solution 

 around its roots. It belongs to a group 

 of tropical grasses characterized by the 

 C-4 photosynthetic pathway. These plants 





The principal features of the plant 

 cover apparent to the observer are the 

 variations in height, density, and color 

 of the sward rather than the presence of 

 other species (Figure 5). A few other 

 species can be found in the low marsh, 

 however. Sea lavender ( Limonium nashii ) 

 is the most common "other plant" in the 

 New England low marsh. There are 

 occasional glassworts ( Sal icornia ) , 

 especially where the marsh has been 

 disturbed. We have also found other 

 plants growing in the regularly flooded 

 intertidal areas: seaside aster ( Aster 

 tenuifol ius ) ; spike grass ( Distich! is 

 spicata ) ; gerardia, a small purple flower 

 called by its generic name ( Gerardia 

 ( =Agal inis ) maritima ) , that is 

 semiparasitic on marsh grass roots; salt 

 patens ) ; and sand spurrey 

 marina ). But these 

 alterniflora" plants are 



hay ( Spartina 



( Spergularia 



"non- Spartina 



much more common on the high marsh than in 

 low marsh. Widgeongrass ( Ruppia maritima ) 

 occurs in pools and creeks within the low 

 marsh area, but these areas are not really 

 a part of the regularly flooded marsh. 



Spartina alterniflora is a 

 rhizomatous, coarse grass that can grow to 

 as much as 3 m in height and has a number 

 of adaptations for life in salt marshes. 

 Like most wetland plants, it has a 

 mechanism for supplying oxygen to its 



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■'31 



Figure 5. Spartina alterniflora growing 

 on banks of tidal creeks, Massachusetts. 

 Photo by J.M. Teal, Woods Hole 

 Oceanographic Institution. 



11 



