ILLINOIS TREES: SELECTION. PLANTING. AND CARE 



57 



down elm (opposite page 1) and globe elm (Fig. 2). Camper- 

 down elm (U. glabra camperdowni) has strong, crooked branches 

 that grow downward to give the tree a weeping appearance. 

 Globe elm {V . carpinifolia umbraculifera) has numerous slender 

 branches that grow upward to give the tree a globe appearance, 



American elm (opposite page 1 and Fig. 4 and 56) has been 

 extensively planted throughout the state for shade and orna- 

 mental purposes and occurs in abundance in woodlands. The 

 pointed-tipped, coarsely toothed, elliptical-shaped, alternate 

 leaves (Fig. 56 inset), 4-6 inches long and 1-3 inches wide, are 

 dark green, smooth and shiny or somewhat rough above but paler 

 and usually soft-hairy beneath. The small, reddish, perfect flow- 

 ers, borne on slender stalks up to 1 inch long, appear before the 

 leaves in early spring. The i/o-inch-long, light green, oval, winged 

 fruit contains a single seed. The thick, rough, ash-gray bark 

 (Fig. 23) is broken into broad ridges separated by deep fissures 

 and is corky white or gray in spots. 



The elms, especially American elm, are subject to attack by 

 various insect pests including cankerworms, aphids, scales, bark 

 beetles, leafhoppers, and mites. Of the diseases that affect elms. 



Fig. 56. — Ameri- 

 can elm, with its 

 coarsely toothed, el- 

 liptical leaves (in- 

 set), has been the 

 most universally 

 planted shade tree 

 in the midwestern 

 states for genera- 

 tions. However, it is 

 being decimated by 

 two diseases, elm 

 phloem necrosis and 

 Dutch elm disease. 



