INTRODUCTION 



In the Preface to Edward Tatnall's Catalogue of plants of New 

 Castle County, published in 1860, the author quotes the belief of 

 Dr. William Darlington, that "New Castle County possesses a 

 richer flora than any other county in the Union." While this 

 opinion, expressed more than eighty years ago, is hardly tenable in 

 the light of present-day knowledge, yet it is true that the Peninsula 

 of Delaware, Maryland and Virginia, of which New Castle County 

 is a part, is a natural geographic unit of exceptional interest botan- 

 ically, with a flora exceeding in variety most areas of like extent in 

 the eastern United States. This peninsula includes in its northern 

 portion a strip of upland, with rocky, wooded hillsides, and rich 

 alluvial soil of stream valleys. Farther south it presents a variety 

 of plant habitats characteristic of the coastal lowlands. 



The Peninsula of Delaware, Maryland and Virginia, as here 

 defined, is the region lying south of the southern boundary of 

 Pennsylvania, and bounded on the east by the Delaware River and 

 Bay and the Atlantic Ocean, and on the west by the Susquehanna 

 River and Chesapeake Bay. It thus includes the entire state of 

 Delaware, nine counties of Maryland (or about one-third of the 

 land area of that state), and two counties of Virginia. Its length, 

 north to south, is roughly 200 miles, and its greatest width 70 miles. 

 Its total land area is about 6057 square miles. 



Phytogeographic Regions or Provinces. Two very distinct 

 natural "provinces" are involved in the make-up of the Peninsula, 

 namely, the Coastal Plain and the Piedmont Plateau. Each of 

 these has a characteristic flora, differing in many interesting re- 

 spects from the other. 



The Coastal Plain of the Atlantic states is a low-lying strip of 

 land along the seacoast. which in recent geological time has been a 

 portion of the ocean floor. Its inner or landward limit is the line 

 marking the farthest encroachment of the sea during the periods of 

 submergence. Beyond the inner margin of the Coastal Plain the 

 ground rises somewhat abruptly to a height of several hundred feet 

 above sea-level, forming an area of more or less uniform altitude, 

 extending inward toward the mountains. This is the Piedmont 

 Plateau. As the name impUes, it may be regarded as a foot-hill 



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