140 THE PLANT LIFE OF MARYLAND 



acre, Acnida cannabina, and Ly thrum lincare. Area II. is above 

 mean tide-level and bears a turf of Spartina patens. Scattered in- 

 dividuals of depauperate Spartina polystachya occur in the outer 

 margin of area II. and along the stream are a few plants of Acnida 

 cannabina. In area VI. there is considerable Distichlis spicata in- 

 termingled with Spartina patens. Area III. is a mixed stand of 

 Typha angustifolia, Scirpus robustus and Acnida. Areas IV. and 

 V. are stands of Typha angustifolia with Polygonum acre and Svum 

 c i cutae folium. Area VII. is the characteristic marginal zone of 

 Hibiscus moscheutos and Baccharis hal mini i folia. 



Aquatic Vegetation. 



The waters of the Chesapeake Bay and the larger estuaries con- 

 tain a relatively poor algal flora as compared with those parts of the 

 Atlantic coast where there are rocks and boulders serving as points 

 of attachment. Species of Ulva, Enteromorpha and Cladophora 

 are the commonest Green Algae along the shores and in the shal- 

 lower waters. The Brown Algae are represented chiefly by Ecto- 

 carpus, and the Red Algae by several species of Ceramium and by 

 Dasya elegans. The Phanerogamic aquatics of salt water are only 

 two in number, Zostera marina, which is most abundant along the 

 shores of Chincoteague Bay and the lower Chesapeake, where the 

 water is violently agitated by the waves ; and Ruppia maritima. 

 which is abundant on muddy bottoms in shoal water not only in 

 salt water but in brackish and fresh parts of the longer estuaries. 



The Phanerogamic aquatics are much more abundant in the fresh 

 waters about the head of the Bay and in the Chester, Sassafras, 

 Bohemia, Elk and North East rivers. The commonest of these is 

 Vallisneria spiralis, which under the name "Wild Celery" is well 

 known as an important food-plant of the wild duck. Vallisneria is 

 extremely abundant in the shallow waters about the head of the Bay, 

 where, at low tide, the floating ends of the ribbon-like leaves betray 

 its presence over areas many acres in extent. Potamogeton crispus 

 is often associated with Vallisneria, ami lias been noticed to be par- 

 ticularly abundant in the Chester and Sassafras rivei*s. These 

 aquatics grow where they are subjected to the pull of strong 



