502 SOILS. 



In all these variations of the tree forms, there is also a con- 

 comitant variation in the forms and other characters of the 

 leaves. Thus in the compact forms of the black-jack oak, the 

 trilobate leaf is almost completely obliterated, the leaf being 

 simply rounded-cuneate, somewhat auriculate at base. In the 

 sparse-branched upland forms the leaves are deeply three- 

 lobed, and the ferruginous tomentum of the lower surface is 

 much less pronounced. The lobation of the post oak also 

 varies considerably both in the numbers of lobes and in their 

 obtuseness. Similar differences prevail in the case of the 

 black and Spanish oaks; thus in the latter, the long terminal, 

 falcate lobe is always most pronounced on " rich " soils, while 

 on poor ones the trilobate leaf predominates. 



Of course all these forms may be found bearing acorns, so 

 that they undoubtedly represent adult trees. 



Characteristic Forms of other Oaks. Similar general fea- 

 tures are repeated in the case of the other species of oaks, and 

 also more or less in other kinds of trees; though mostly less 

 pronouncedly than with the two species above described. 

 Among the more striking are the two forms of the willow oak 

 (Q. phellos), which on low, undrained ground assumes the 

 low, rounded, " apple-tree " form, while on well-drained up- 

 lands of good fertility it is a beautiful, slender tree producing 

 almost the effect of the acacia type; it is then a sign of first- 

 class land. The scarlet oak rather reverses these stypes; on 

 good, " brown-loam " upland it is of rounded form, not very 

 tall, with sturdy, rough-barked trunk ; while on poor hillside 

 lands its tall, smooth, white trunk stands out as a conspicuous 

 admonition to the landseeker to beware of a poor purchase. 

 The black and Spanish oaks also indicate, by tall thin trunks, 

 a deterioration of the land as compared with the lower and 

 more sturdy growth on areas relatively richer in lime. 



Sturdy Growth on Calcareous Lands. One feature invari- 

 ably repeated, not only in Mississippi but throughout the 

 United States, is that /;/ man\ strongly calcareous soils the 

 growth of all trees, as well as of shrubs and of many herbace- 

 ous plants, is of a more sturdy and thick-set habit than that 

 of the same species grown on thin, sandy, or generally on non- 

 calcareous land. This effect is quite as apparent in the arid 



