68 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 51 



are borne on the same tree. The dark, reddish-brown fruit de- 

 velops as a flattened, twisted pod 10-18 inches long and 1-1 V2 

 inches wide. Each pod contains several hard, oval seeds embedded 

 in sweet, yellow pulp. Selections of the thornless honey locust 

 which grow very rapidly and do not produce seeds are available. 

 The 1/2- to %-inch-thick bark is divided into long, longitudinal 

 ridges by deep fissures and the surface is roughened by small 

 persistent scales. 



Thornless honey locust is relatively free of diseases. How- 

 ever, the foliage may be seriously damaged by bagworm, pod' 

 gall, mimosa webworm, and locust mite. The hard, strong, 

 reddish-brown, coarse-grained wood of the honey locust is very 

 durable in contact with the soil. It is used extensively for fence 

 posts and railroad ties and to a limited extent as lumber. 



Hop Hornbeam 



Hop hornbeam or ironwood {Ostrya virginicina) (Fig. 65) 

 is a small, native, slow-growing tree that reaches a height of 25- 

 30 feet with a branch spread of 20-30 feet. Mature trees usually 

 develop open, round-topped crowns of slender branches. It 



Figr. 65.— The small, 

 slow-g^rowing hop horn- 

 beam, with its elmlike 

 leaves (inset) and hop- 

 like fruit, is suitable as an 

 occasional tree in orna- 

 mental plantings. 



