66 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 51 



lar to that of the shellbark hickory except that the tips of the 

 bark plates remain flattened against the trunk. 



Bitternut, with its rounded, broad-topped crown and stout, 

 ascending branches, grows to a height of 40-65 feet, with a 

 branch spread of 25-30 feet. It grows along streams and on rich 

 bottomlands throughout Illinois. The 6- to 9-inch-long, compound, 

 alternate leaves are made up of seven to nine leaflets. The firm, 

 coarsely toothed leaflets are 4-6 inches long, 34-ll^ inches wide, 

 smooth and dark green above and paler with hairs on the midrib 

 beneath. They vary in shape from elliptical to lance shaped. The 

 flowers are similar to those of shellbark hickory. The oval to 

 oblong, reddish-gray to brown, thin, brittle-shelled nut with its 

 bitter kernel is encased in a thin, somewhat hairy, globose to ob- 

 long husk, ¥1.-114 inches long and % inch or less thick, which 

 bears four wings. The thin, light gray bark of bitternut remains 

 smooth for many years. However, on old trees it forms narrow, 

 firm, interlacing, flaked ridges separated by shallow fissures. 



Mockernut grows to a height of 50-80 feet, with a branch 

 spread of 25-30 feet. It develops a narrow, oblong crown of up- 

 right, rigid branches or a broad, round-topped crown of grace- 

 ful and somewhat drooping branches. It grows throughout most 

 of the state but is absent from northern and northeastern 

 counties. It is more common in the south and occurs more often 

 on dry slopes and ridges than on bottomlands. The 8- to 12-inch- 

 long, compound, alternate leaves are made up of five to seven or 

 sometimes nine leaflets. The lustrous, sharply pointed, toothed, 

 oblong to lance-shaped leaflets are 3-7 inches long. The flowers 

 are similar to those of shellbark hickory. The thick, hard-shelled, 

 light reddish-browm nut contains a small, dark brown, sweet 

 seed. It is covered by a strong-scented, reddish-brown. 14-inch 

 thick husk w^hich splits nearly to the base on ripening. T, e entire 

 fruit is oval to round or slightly pear shaped and 11/4-2 inches 

 long. The thin, gray bark has low, rounded ridges divided by 

 shallow, irregular furrows. 



Hickories are subject to damage from ice, wind, leaf spot 

 diseases, and insect pests, especially the hickory bark beetle. 

 Leaf spot diseases may cause rather severe dropping of leaves or 

 premature defoliation in some years. Usually, however, they 

 are not serious and cause very little noticeable permanent injury. 

 The hard, heavy, strong, close-grained wood of hickory is tough 

 and durable and is one of the most extensively used woods in 

 industry. 



