ILLINOIS TREES: SELECTION. PLANTING, AND CARE 



67 



Honey Locust 



Honey locust {Gleditsia triacanthos) , which prefers an alka- 

 line soil, is widespread in the state, while water locust (G. aqua- 

 tica) grows only on the swampy bottomlands of the Mississippi, 

 Cache, Ohio, and Wabash rivers in southern Illinois. The typical 

 forms of both species are very thorny and unsuited for orna- 

 mental purposes. The thornless form (Fig. 64) of honey locus'^ 

 (G. triacanthos forma inermis) grows satisfactorily in variods 

 types of soil and is used widely in street and lawn plantings. It 

 grows rapidly, and may reach a height of 70-80 feet, with a 

 branch spread of 60-70 feet. 



The large, alternate, compound leaves (Fig. 64, left inset), 

 7-10 inches long, are composed of 18-28 small, shiny, dark green 

 leaflets which are about 1 inch long and Vi inch wide. Some 

 leaves are doubly compound (Fig. 64, right inset) and composed 

 of 8-14 singly compound leaves. The inconspicuous, yellowish- 

 green flow^ers appear in June when the leaves are nearly full 

 grown and are attractive to bees. The male flowers are short, 

 many-flowered, pubescent clusters. The female flowers are 

 slender, single- to few-flowered clusters. Male and female flowers 



Fig. 64.— Thorn- 

 less honey locust has 

 been used extensive- 

 ly where elms have 

 been killed by dis- 

 ease. Its compound 

 leaves (left inset), 

 composed of 18-28 

 small leaflets, pro- 

 duce light shade. 

 Some leaves are 

 doubly compound 

 (right inset) and 

 composed of 8-14 

 singly compound 

 leaves. 





