CHAPTER XXVIII: THE ELMS AND THE 

 HACKBERRIES 



Family ULMACE/ii 



1. Genus ULMUS, Linn. 



Trees of horticultural and lumber value. Leaves alternate 

 serrate, unequal at base, with strong ribs and short petioles 

 Flowers greenish, inconspicuous, perfect. Fruit a dry nutlet 

 with thin encircling wing, bearing two hooks at apex. 



KEY TO SPECIES 



A. Blooming before the leaves in spring. 

 B. Twigs smooth. 



C. Branches corky winged. 



{U. alaia) wahoo or winged elm 

 CC. Branches not corky winged. 



{U. Americana) American or water elm 

 BB. Twigs pubescent. 



C. Branches corky. {U. Thomasi) cork elm 



CC. Branches not corky; leaves rough above; twigs and 

 buds with coarse, rusty hairs. 



{U. julva) slippery elm 

 AA. Blooming late in summer or autumn. 



B. Leaves over 2 inches long, thin. {U. seroiina) red elm 

 BB. Leaves i to 2 inches long, thick. 



{U. crassijolia) cedar elm 



2. Genus CELTIS, Linn. 



Valuable shade trees. Leaves simple, 3-nerved, serrate. 

 Flowers polygamo-monoecious, axillary, small. Fruit sweet, 

 succulent berry. 



A. Leaves coarsely and sharply serrate; fruit large. 



(C. occidenialis) hackberry 

 AA. Leaves entire or obscurely serrate; fruit small. 



(C. Mississippiensis) sugarberry 

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