THE HICKORY-NUTS OF NORTH AMERICA. 



73 



rates into pieces, the flowers are alike, and the bark exfoliates in much 

 the same way in both. There are, however, often seven instead of five 

 leaflets, but they have a pointed apex and serrate edges. The tree is 

 not so widely distributed over the country, as it is found mainly in 

 the Mississippi Valley, north of the Ohio 

 River. The very heavy shell, requiring 

 severe blows with a hammer to crack, 

 makes the reason for this more limited 

 diffusion obvious. Depending almost 

 solely on rodents for its dispersal, the 

 size of the nuts preventing the wind 

 from carrying them to any distance, the 

 heavy shell makes it a most difficult task 

 for the gnawers to penetrate to the ker- 

 nel within. It will be readily understood 

 that the thinner and yet sweet-kerneled 

 nuts will be chosen in preference. And 

 while mice and woodchucks and chip- 

 munks and squirrels will lay up stores of the thin-shelled nuts, often 

 carrying them long distances, the heavy-shelled ones will seldom be 

 molested, but remain where they fell near the parent tree. The heavy 

 shell would, again, be an impediment to germination, and thus fewer 

 individuals would grow, and those which did sprout would have little 

 chance of attaining maturity while overshadowed by the older tree. 

 Thus we have a simple explanation of the fact of the limited distri- 

 bution and the small number of individuals in any given area. 



The near ally of this species is another heavy-shelled sort, the 

 mocker-nut, which has a much thinner husk and yet a thick shell. 



Fig. 2.— Thick Shell-babe. (Carya sul- 

 cata). 



Pig. 3.— Mocker-nut (Carya tomentosa). 



The nut is quite large, intermediate in size between the white and the 

 thick shell-bark, of a yellowish color and a sweet kernel. The bark 

 has not the scaling propensity, but the flowers and the leaves are quite 

 similar. Its distribution is wider than the thick shell-bark, but it is 

 still limited. One peculiarity is observed in all three species, and that 



