THE TBEE AND ITS FORMS. 25 



common in eastern Texas. The water hickory is common only along 

 the lower Mississippi and in eastern Texas, and nutmeg hickory, the 

 rarest of them all, grows mainly in southeastern Arkansas. 



SOIL AND MOISTURE REQUIREMENTS. 



In general, the hickories are exacting in their soil requirements, 

 though in this respect there is a wide variation within the genus. 

 Stunted mockernuts grow in Alabama and 'Mississippi upon the 

 sandy shortleaf and loblolly pine land; the drought-enduring pale- 

 loaf hickory grows on the dry hillsides of western Arkansas and 

 Missouri; pignut and mockernut grow in dry situations, such as west 

 and south slopes, or dry ridges in the Cumberlands, or the knobs of 

 southern Indiana. In all these drier situations, however, the trees 

 are likely to be stunted, defective, and usually badly bird pecked; 

 even the drought-enduring species requires for good development 

 soils that are moderately fresh and fertile. Most of the merchantable 

 mockernut and pignut grows on fairly fertile uplands with white oak, 

 black oak, scarlet oak, and post oak, and the very best development 

 is attained only on fresh, deep, fertile soil. Pignut in particular 

 responds readily to the increased fertility of the soil, and in the coves 

 of the Cumberland Mountains, associated with white oak, red oak, 

 yellow poplar, basswood, buckeye, white ash, beech, maple, and shag- 

 bark, it is the largest of the hickories. On the river bottoms of the 

 Mississippi it attains larger dimensions than -any other hickory, 

 except the pecan. 



At the other extreme, water hickory grows with cypress where the 

 ground is wet all the year round and water stands during most of the 

 year. Pecan and nutmeg hickory are only a little less moisture 

 loving. They grow usually on the overflow lands of the South, asso- 

 ciated with sweet gum, tupelo, white oak, cow oak, overcup oak, 

 white and blue ash, and but rarely grow in drier situations except 

 when planted there. Big shellbark and bitternut also are moisture- 

 loving species. The former grows usually in river bottoms or on the 

 banks of streams throughout its range, associated with elm, white 

 ash, white oak, cow oak, overcup oak, and shagbark hickory; the 

 latter, which has a more northern distribution, grows along streams, 

 on rich bottom lands, and on north and east slopes associated with 

 elm, white, red, and pin oak, white ash, shagbark and big shellbark 

 hickory. The widely distributed shagbark shows to a marked degree 

 the tendency to seek moister situations in its southern range and 

 drier ones to the north. In the Ohio Valley it grows chiefly on fertile 

 uplands on north and east slopes; in the Cumberlands it is con- 

 fined to the coves and to north and east slopes. At lower elevations 

 southward it seeks- moister situations, and in Arkansas, Mississippi, 

 and Louisiana grows only in the river bottoms. Throughout its 

 range shagbark is commonly associated with white oak and white ash, 

 517G2 Bull. SO 1( 



