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THE POPULAR SCIENCE MONTHLY. 



is the great variability in the shape of the nuts, a feature that is much 

 less marked in all the other sorts. 



The white shell-bark occupies a sort of intermediate position in the 

 genus. On one hand are the thick-shelled species already noted, form- 

 ing one line, and on another line are two species marked in other ways, 

 but mainly by a difference in the kernel. While in the three already 

 described this is sweet and palatable, in these other two it is bitter 

 and uneatable. These have, also, thin instead of thick husks, and 

 they separate only about half-way down instead of into four distinct 

 pieces. The shell is thin, so much so in some cases as to be easily 

 crushed in the fingers. In size, shape, and markings there is none of 

 the variability of the shell-bark. Of the two species the bitter-nut is 



Fig. 4.— Bitter-nut (Carya amara). 



the more common. The bark is close ; the tree grows to be forty or 

 fifty feet high, the shell is smooth, sharp-pointed, and marked with lines, 

 while the kernel is so bitter that it is rejected by squirrels and other 

 animals as long as other food can be obtained. The leaflets are small, 

 from seven to nine in number. Its distribution is limited to nearly the 

 same area as the mocker-nut, namely, the valleys of the Ohio and its 

 tributaries, Minnesota, Kansas, and "Western New York. 



Fia. 5.— Water-Hickory ( Carya aqitalica). 



Fio. 6.— Small-fruited Hickory (Carya micro- 

 curpa). 



The water-hickory has many of the same features, but the shell of 

 the nut is thinner still, and the kernel yet more bitter, while the tree 

 is confined to the swamps of Carolina and Georgia, where it is by no 

 means common. Its nut is of a reddish color, and more or less angular. 



On a third line running from the white shell-bark are three other 

 species. One of these is the small-fruited hickory, in which the husk 

 and the shell are both thin, and the kernel, though small, is eatable. 

 It is closely allied to the white shell-bark, and by some considered a 





