FORMATION OF LEAFMOLD COVILLE. 339 



of such hills are black jack oak {Quercus marilandica), trailing 

 arbutus, wild pansy (Viola pedata), azalea, and huckleberry, all 

 plants adapted to acute conditions of acidity. If one's front yard 

 happens to coincide with what was once such a spot, let him not 

 undertake the herculean task of growing roses and a bluegrass turf. 

 Let his lawn be of redtop and his shrubs be azaleas, laurel, and rhodo- 

 dendrons. 



Another factor that contributes to the suspension of leaf decom- 

 position is the acid leachings from each new deposit of autumn 

 leaves. Various acidity determinations show that after lying ex- 

 posed to the weather over winter, leaves ordinarily have only one- 

 fifth to one-tenth the acidity they possessed when they fell to the 

 ground. It has been found experimentally that the leachings from 

 fresh leaves will serve to acidulate an underlying soil of moderate 

 alkalinity. Unless, therefore, the conditions of a locality are such 

 as to effect the decomposition of one year's leaf fall before the next 

 year's deposit takes place, a permanent acid leaf cover is established. 

 In many of the oak forests on the sandy coastal plain eastward from 

 Washington there is a permanent accumulation of such material. 

 The roots of the trees and undershrubs bind the half-rotted leaves 

 into a dense mat. The principal trees are oaks. The principal 

 shrubs that make up the dense underbrush belong to the Ericaceae 

 and related families. There is no mellow leafmold nor any of the 

 leafmold plants. 



This kind of mat or turf is of such widespread occurrence, is so 

 distinct in its appearance, and so characteristic in the type of 

 vegetation it supports that it should have a name of its own, in order 

 that it may come to be recognized as one of the important pheno- 

 mena of nature. 



Because of its resemblance to bog peat in appearance, structure, 

 and chemical composition, and because it supports a type of vege- 

 tation similar to that of bog peat it has been proposed to adopt for 

 it the name upland peat. As defined in an earlier publication,^ 

 upland peat is " a nonpaludose deposit of organic matter, chiefly 

 leaves, in a condition of suspended and imperfect decomposition and 

 still showing its original leaf structure, the suspension of decompo- 

 sition being due to the development and maintenance of an acid con- 

 dition which is inimical to the growth of the microorganisms of 

 decay." 



Upland peat would have become leafmold had not the orderly 

 normal course of leaf decomposition been suspended and conditions 

 of acidity established which rendered the further progress of that 

 decomposition impossible. 



1 Coville. IDIO. p. 34, Esperimeuts in blueberry culture, Bulletin 193, Bureau of Plant 

 Industry, U. S. Department of Agriculture. 



