20 



THE COMMERCIAL HICKORIES. 



leaf stocks, in many cases so numerous as to resemble " witches 

 broom." 



In habit the big shellbark is rather shorter and has heavier branches 

 than the shagbark. Generally it is a smaller tree, though in south- 

 eastern Missouri it attains a height of from 120 to 130 feet and a 

 diameter of 40 inches breast-high. 



PIGNUT. 



In botanies and tree manuals the name commonly given to Ilicoria 

 glabra is " pignut." A tremendous amount of confusion results from 

 this, because in common usage, throughout the whole range of the 



hickories, the term pignut is 

 applied to an entirely differ- 

 ent tree (Hicoria minima). 

 The names in common use in 

 the order of their frequency 

 are black hickory, tight 

 bark, switch-top, or simply 

 hickory. 



Of all the hickories none 

 is more important and none 

 offers more difficulties to the 

 botanist. It is exceedingly 

 variable and grows under 

 widely differing conditions 

 of soil and climate. Be- 

 tween four types or vari- 

 ants, which recently have 

 been segregated, there are 

 many intermediate forms. 



FIG. 7. -Pignut (Hicoria glabra). Twigs, natural size; leaf J n ^he typical qlobrCL the 

 and fruit, one-third natural size. . J * 



bark is generally dark gray 



in color, and is somewhat flaky or scaly, but never scales off in 

 long plates like the shagbark. In old trees it is strongly ridged, much 

 as that of white ash or elm. The leaflets, leaf stalks, twigs, and 

 buds are entirely free from hairs. The branchlets are slender and 

 the buds small. There are from 5 to 7 leaflets. The fruit is generally 

 pear-shaped and the husk splits less than halfway to the base. The 

 nut is smooth and round, with a thin shell. The kernel is likely to 

 be sweet, but is not easy to get out. 



The variety microcarpa, which is the common one of the Ohio 

 Valley and which many botanists now describe as a distinct species, 

 has rather coaser twigs than the typical glabra. The fruit is smaller 

 and is less frequently pear-shaped; the husk commonly splits freely 



