62 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 51 



Fig. 61. — Hackberry 

 is relatively free of dis- 

 eases and insect pests 

 except for witches'- 

 broom. The leaves (in- 

 set) are somewhat sim- 

 ilar in size and shape 

 to leaves of American 

 elm but are lighter 

 green in color. 



ing to 50 feet. Mississippi hackberry grows mostly on bottom- 

 lands in the southern third of the state. Hackberry is relatively 

 tolerant of city conditions, and both species are used for shade 

 and ornamental purposes. 



The long, thin, sharply pointed, light green, alternate leaves 

 (Fig, 61 inset) are 2-5 inches long and 1^2-2 inches wide. The 

 margins are sharply toothed on hackberry and smooth on Missis- 

 sippi hackberry. The small, cream-colored to greenish flowers 

 are inconspicuous, and male and female flowers are borne sep- 

 arately on the same tree, the female flowers singly and the male 

 flowers in small clusters. The small, round, berry-like fruit meas- 

 sures V^-Vs i^^ch in diameter. It is orange-red to yellow on Mis- 

 sissippi hackberry and orange-red, turning to dark purple, on 

 hackberry. The bark of hackberry (Fig. 28) is dark brown and 

 broken up into corky ridges, while the bark of Mississippi hack- 

 berry is pale gray and covered with corky warts. Hackberry 

 wood is used mainly for posts and cheap furniture. 



Hackberry is relatively free of diseases and insect pests ex- 

 cept for witches'-broom. The formation of witches'-broom is 

 associated with a powdery mildew fungus and a gall mite. The 



