14 



THE COMMERCIAL HICKORIES. 



by an indigenous species (Hicoria mexicana) and by the pecan and 

 the nutmeg hickory. 



The fruit of the hickory is the most unmistakable characteristic 

 of the genus. In general it is much like that of the walnut a nut 

 with a single two-chambered kernel, each chamber partially sepa- 

 rated into two lobes. The shell, however, is smooth on the out- 

 side, and the husk, instead of being entire, splits into four segments, 

 usually from the apex to the base, and allows the nut to drop out. 

 In size and shape, and in other ways, the nuts vary greatly in the 



different species. The 

 nut of the big shellbark 

 is often an inch and a 

 half in diameter and has 

 a thick, hard shell, while 

 that of the bitternut 

 and the water hickory 

 is small, only about J 

 inch in diameter, with a 

 thin shell and thin husk. 

 The best known forms 

 are the pecans and the 

 shagbarks, which form 

 important articles of 

 commerce. The big 

 shellbark and the mock- 

 ernut also produce edi- 

 ble nuts, but those of 

 the bitternut and water 

 hickory are quite astrin- 



FIG. 1. Pecan (Hicoria pecan). Twig, natural size; leaf and 

 fruit, one-third natural size. 



compound, with three 

 to fifteen leaflets, ar- 

 ranged in opposite 

 pairs, with a single rather larger leaflet at the end. The leaves are 

 arranged alternately on the twigs. This feature offers a ready 

 means of distinguishing the hickories from the ashes, which have 

 opposite leaves. The pith is solid and not chambered as in the 

 walnuts. 



The hickories are characterized by a very strong taproot. In no 

 other genus in this country is the taproot developed to a greater 

 extent. (See PL III, fig. 1, p. 16.) The size of the taproot varies, 

 however, with the species and with the situation. It has its great- 

 est development in the drought-enduring species and in the drier 

 situations. In wet river bottoms the taproot is not so well developed. 



