ILLINOIS TREES: SELECTION, PLANTING. AND CARE 



63 



broomlike growths are composed of clusters of dwarfed shoots 

 that grow from swollen or enlarged areas on branches. They are 

 more conspicuous during the winter when the trees are without 

 leaves. No effective cure is known for this trouble. When ob- 

 jectionable, the brooms may be removed by pruning. American 

 hackberry is more susceptible to witches'-broom than Mississippi 

 hackberry. 



Hawthorn 



Hawthorns, as illustrated opposite page 1 (cockspur thorn) 

 and in Fig. 62 (Washington thorn), are very hardy, small trees. 

 Some hawthorns are used extensively in ornamental plantings 

 because of their showy white, pink, or red flowers and attractive 

 red fruit. The alternate, simple leaves (Fig. 62 inset) are gen- 

 erally toothed and often more or less lobed. They vary on differ- 

 ent species from yellowish-green to dark green and shiny. The 

 perfect flowers are produced in small to large groups on the ends 

 of short, leafy, side branches. The round to oblong, dry, mealy 

 fleshed fruit is bright or orange-red in color and is called a 



Fig. 62. — Several spe- 

 cies of hawthorn are 

 prized as ornamental 

 trees, but in some years 

 they are severely defoli- 

 ated by the cedar rusts, 

 and individual plants 

 may be damaged or 

 killed by fire blight. In- 

 set shows a toothed and 

 lobed leaf of Washing- 

 ton thorn. 



