MARYLAND WEATHER SERVICE 125 



The Cypress first appears in ascending the Pocomoke River at 

 ( !edar Hall Landing, and a few small trees are to be seen opposite 

 Kehohoth on the outer edge of the broad brackish marsh. At a 

 point about a mile and a half above Rehoboth the brackish marsh 

 terminates abruptly and the River Swamps occupy the margins of 

 the river. The narrowness and deepness of the Pocomoke are not 

 favorable to the occurrence of extensive pure stands of Cypress, and 

 at most localities there are several other tree species associated with 

 it. The characteristic peculiarities of the Cypress, the swollen base 

 of the trunk and the "knees," are not very markedly developed in 

 the second growth trees along the Pocomoke, but may be observed 

 in the trees of the pure stand in Newhope Pond, an old artificial 

 millpond near Willard, which is crossed by the Baltimore, Chesa- 

 peake and Atlantic Railway. Below Mattaponi Landing there is 

 no emersed aquatic vegetation outside the Swamp, but there are a 

 few places on the convex sides of the river where there are narrow 

 zones of such plants as are characteristic of the Fresh Marshes. 

 Above Mattaponi a zone of Nymphaea aducna and Pontederia cor- 

 data is almost continuous along the outer margin of the Swamp. 



The River Swamp occupies a narrow shelf which rises as one 

 advances from the river back toward the Upland, and decreases 

 in the frequency of inundation by the fluctuating level of the river. 

 It is in the outer zone of the Swamps that the Cypress is most 

 abundant, the inner zone often bearing a near resemblance to the 

 Sandy loam Upland Swamps. The most abundant associates of 

 the Cypress are Black Gum, Red Maple, Sweet Gum, Tupelo, Green 

 Ash and Magnolia. Less abundant are Tulip tree, Winterberry, 

 Hornbeam, Swamp Poplar, Water Oak and White Cedar. In the 

 inner zone of the Swamps the Loblolly Pine, White Oak and Holly 

 also occur, the Cypress becomes less abundant and the Black Gum, 

 Bed Maple and Sweet Gum more so. 



The undergrowth of the River Swamps is usually rather thick 

 and is rich in species. Frequent and characteristic are: 



Myrica cerifera 

 Clethra alni folia 

 Xolisma li gastrin a 



