THE TREE AND ITS FORMS. 



21 



to the base and the bark is likely to scale off in flat scales, somewhat 

 like shagbark, though much less pronounced. Some botanists also 

 distinguish another variety, odorata, which differs in having larger 

 nuts, and a yellowish glandular pubescence in the buds, leaves, and 

 twigs. 



The pale-leaf hickory (Hicoria villosa) is a distinct species, but it 

 also may be placed in the pignut group. It is a xerophytic, or drought- 

 resistant, species, and grows mainly in Arkansas and Missouri. It 

 resembles the mockernut in many characteristics and particularly in 

 the bark, which is likely to be deeply fissured and rough, but not 

 shaggy, and has diamond-shaped checks, as in the Mississippi Valley 

 form of the mockernut. 

 The twigs are slender, and 

 twigs, buds, and leaves are 

 covered with a yellowish 

 pubescence. There are 

 from 7 to 9 leaflets, gener- 

 ally small, narrow, thick, 

 dark green, and shiny on 

 the upper side. The fruit 

 varies considerably both in 

 size and shape and often 

 resembles that of the mock- 

 ernut; but typically it is 

 spherical, with a moder- 

 ately thin husk, slightly 

 ridged at the sutures, and a 

 thick-shelled, rounded nut, 

 much like that of pignut 

 or mockernut. The tree is 

 rarely more than 60 or 70 

 feet high. Another species, 

 pallida, resembles the vil- 

 losa very closely. It, also, is a xerophytic species, and grows on 

 the hills of Tennessee, Kentucky, and North Carolina. It has the 

 same yellowish pubescence on twigs, buds, and leaves, except that 

 on the leaves the pubescence is rather more woolly. The fruit also 

 is similar, but is somewhat more winged. Frequently the bark is 

 broken into small cubes somewhat like those of the black gum. 



MOCKERNUT. 



The mockernut (Hicoria alba), known also as the "big bud," 

 "white heart/' "white hickory," and "hognut," is most easily recog- 

 nized by its coarse, hairy leaves and twigs. The leaves have gen- 



FIG. 8. Small pignut (Hicoria odorata). Twig, natural 

 size; leaf and fruit, one-half natural size. 



