THE ECOLOGICAL PLANT GEOGRAPHY 



OF MARYLAND, MIDLAND ZONE; 



LOWER MIDLAND DISTRICT 



FOEEEST SHEEVE 



Introductory. 



As contrasted with the Coastal Zone the Lower Midland District 

 is very uniform throughout in its physical conditions, and it is the 

 least diversified in its vegetation of any of the ecological districts 

 of the state. Whereas the topography of the Coastal Zone is such 

 as to present a number of types of Marshes and Swamps, to say 

 nothing of the sharp contrast in soils, the Lower Midland has been 

 eroded with such uniformity that differences of topography are re- 

 sponsible for only minor distinctions of habitat. By far the most 

 important differential factors in determining the local distribtition 

 and association of plant life in this District are those concerned in 

 the character of the soils. In the Introduction attention has already 

 been called to the types of soil which overlie the various geological 

 formations of the Piedmont Plateau, and to the fact that the chem- 

 ical as well as the physical characteristics of these soils play an 

 important role in relation to plant life. The influence of the topog- 

 raphy is not inconsiderable, but operates in a similar manner on 

 each of the major soil types. On the topland* the influence of the 

 soil character is most marked, while on the lower slopes the factors 

 determined by the topography exercise a predominant influence or 

 even offset completely that of the soil character. 



The two northernmost counties, Cecil and Harford, have been 

 mapped by the Bureau of soils in cooperation with the Maryland 



*Topland is a word here used (and perhaps invented) to indicate that level 

 or nearly level part ot the surface of a maturely dissected topography which 

 lies at or near the highest elevation, in contradistinction to the middle and 

 lower slopes of the valleys. 



