MARYLAND WEATHER SERVICE 135 



up stream into the fresh water zone as constituents of this turf. 

 The soil which underlies it is not the pure Galveston clay, as the 

 black muck of the Marshes proper lias heen designated hy the Soil 

 Survey, hut contains a great deal of sand, and the vegetation cor- 

 respondingly comprises some of the herbaceous species of the Sandy 

 Loam Upland Swamps, as Rynchospora glomerata, Xyris communis 

 and Rlicxia mariana. In addition to these are such forms as Eri- 

 ocaulon decangulare, Fimbristylis castanea, Cladium mariscoides, 

 Erianthus compactus, Panicum virgatum, Proserpinaca palustris 

 and Hydrocotyle ranunculoides. 



Just outside the Fresh Marshes there is frequently a narrow strip 

 of muddy shore unoccupied by large perennial vegetation and sub- 

 ject to alternate submergence and exposure. At a few localities 

 these tidal mud flats have been found to bear a sparse growth of 

 small forms, most of which are known only in such habitats, and all 

 but the first two of which are quite uncommon : 



Eleoch aris acicu laris 

 Lilaeopsis lineata 

 Sagittaria subulata 

 Elatine americana 

 Lopliotocarpus spongiosus 

 Sagittaria engelmanniana 

 Limosella tenuifolia 

 Micranthemum micranthemoides 

 Sagittaria graminea 

 Isoctes saccliarata. 



The Fresh Marshes which lie in the transition zone between the 

 broad areas of Salt Marsh and the upland in southern Dorchester 

 County present an extremely uniform aspect over thousands of acres, 

 as seen at Keene Ditch and at several localities near Bestpitch 

 Ferry. The soil of the Marshes at these places is in a constant 

 slate of saturation, is inundated at the time of the highest tides, 

 and is a black muck of the Galveston Clay type. The vegetation 

 is a pure stand of Scirpus olneyi in many localities, or in others a 

 mixture of it and Scirpus americanus. There is an extremely sparse 



