290 THE PLANT LIFE OF MARYLAND 



Bubus hispidus 

 Dryopteris spinulosa 

 Dryopteris cristata 

 Mimulus ririgens 

 Caltha palustris. 



The Swamp at Wolf Gap near Finzel is chiefly of second growth 

 and lias more deciduous trees in its make-up than the Cranesville and 

 Thayerville Swamps. All of the plants thus far named have been 

 seen at Finzel excepting the Tamarack and Taxus minor and Ihcl- 

 oides mucronata. Additional species to those named above are 

 Aronia atropurpurea, Aster acuminatus, Polemonium reptans, 

 Orontium aquaticum, Calf ha flabellifolia, Clintonia horealis. 



Bogs. 



The Bogs of the Mountain Zone are all situated near areas of 

 Swamp or Glade forest, or in places where these forests formerly 

 stood. At Finzel, Thayerville and Cranesville there are typical 

 Bogs, and others have been examined between Oakland and Crelliu 

 and between Oakland and Deer Park. All of the Bogs bear unmis- 

 takable evidence of formerly having been forested, presumably by 

 Spruce and White Fine, and the encroachment upon them of shrubs, 

 chiefly Alders and seedling trees, chiefly Red Maple, indicates that 

 they will rapidly return to forest if undisturbed. In the virgin 

 Swam]) forests there were probably narrow belts of Bog along the 

 streams which traversed them, or perhaps around their edges on the 

 transition line between the Swamp and the Upland. The clearing 

 of the Swamps would result in the occupation of the bare floor by a 

 continuous covering of Sphagnum, into which the characteristic Bog 

 plants would migrate from the area-; already present. 



The typical Bogs of the northern United States are usually found 

 around glacial lakes or in depressions formerly occupied by lakes 

 which have been filled by the accumulation of Sphagnum. Since the 

 topography of the Mountain Zone presents no such habitat favoring 

 the development of Bogs it is not surprising to find them limited in 

 occurrence and size. The species which are dominant in the northern 



