harper: PHYTOGEOGRAPHY of southern MARYLAND 587 



A comparison of the starred species in this and the preceding 

 list, in connection with chemical analyses of representative soils 

 of the two regions, should throw valuable light on the soil pref- 

 erences of the trees involved. In the abundance of chestnut 

 and poplar, and in a few other particulars, this region differs 

 from all other parts of the coastal plain and resembles the Pied- 

 mont region, particularly that part immediately north of the 

 District of Columbia. The chestnut is now badly blighted, 

 and this is said to have happened only in the last three or four 

 years. The undergrowth comprises a remarkable number of 

 herbs with compound leaves (such as Cimicifuga, Phegopteris 

 hexagonoptera, and Botrychium virginianum) or barbed fruits 

 (Cytioglossum, Circaea, Washingtonia, Meibomia), and others 

 that are more characteristic of hilly or even mountainous regions 

 (e.g., Oxalis violacea, Obolaria, Arabis canadensis, Hepatica). 

 Asimina triloba (pawpaw) is one of the commonest shrubs or 

 small trees. The Ericales are almost wanting. The various oaks 

 constitute only about 1 1 per cent of the forest : a very small figure 

 for this part of the world. 



4. THE BRANDYWINE PLATEAU 



This corresponds pretty closely with the area mapped by 

 Maryland geologists as occupied by the Lafayette or Brandy- 

 wine terrace (the latter name taken from the village of Brandy- 

 wine in Prince Georges County). Its northern extremity is 

 near the eastern corner of the District of Columbia, nearly 300 

 feet above sea-level, and it extends southward with gradually 

 decreasing altitude to the vicinity of LaPlata and Charlotte 

 Hall. It is perhaps the best example of a plateau in the whole 

 coastal plain. 



The general surface of the uplands is rather flat, but is deeply 

 dissected by several creeks, some of which cut do^\Ti into the 

 greensand and make fertile valleys a mile or more wide. These 

 valleys have proved a well-nigh insuperable obstacle to build- 

 ing railroads from Washington in the direction of Leonardtown, 



