Visit a salt marsh anywhere in Massachusetts and what you’ll see is an assemblage of grass species, largely indistinguishable from each other to the casual passerby. Although difficult to tell apart from a distance, and sometimes difficult even up close when their flowers or seeds are not present, salt marshes are generally comprised of a variety of species. One of the most common, however, is smooth cordgrass (Spartina alterniflora). S. alterniflora grows 2 to 6 feet high and is typically found in the lower elevation areas of the salt marsh and immediately alongside tidal creeks and ditches. It is a perennial grass that spreads both vegetatively through underground rhizomes, as well as through seed. In July, the spike-like wind-pollinated flower inflorescences are present, helping to distinguish S. alterniflora from the other salt marsh grasses. 

Flowering inflorescence of Spartina alterniflora.

An environment that gets inundated with salt water 50% of each day due to changing tides and is often subject to substantial wave action during storms prohibits the growth of almost all plants. Salt marsh species like S. alterniflora are specifically adapted to survive in these challenging ecosystems. S. alterniflora can tolerate this twice daily flooding due to the presence of a set of tubes running from its leaves down into the hollow spaces between its roots, helping to provide necessary oxygen to the roots when the base of the plant is covered with water at high tides. It is also able to deal with the high salt levels in the water by excreting excess salt through its leaves. In fact, you can see and feel the resulting salt crystals on the surface of its leaves when this occurs. 

Smooth cord grass is considered a pioneer species since they are often the first plants to establish on tidal flats when enough sediment has accumulated to allow the surface to be exposed for at least 6 hours between tides. It is also an effective stabilizer and helps to reduce erosion along coastlines.  Finally, S. alterniflora is of great importance to wildlife. Waterfowl, shorebirds, and songbirds eat the seeds, geese and muskrats each the rhizomes, and deer eat the entire plant. Large patches of S. alterniflora can also provide food, nesting sites, and shelter for many other animals, both above and below the soil, such as fiddler crabs and ribbed mussels. 

Salt marshes and Spartina alterniflora can form fringing patches along the coast…

…or can form large expansive “meadows”.