CHAPTER XXVIII: THE ELMS AND THE 



HACKBERRIES 



Family Ulmace. 



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. alaid) 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. serotina) red elm 

 BB. Leaves i to 2 inches long, thick. 



{U. crassifolia) 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. occidentalis) hackberry 

 AA. Leaves entire or obscurely serrate; fruit small. 



(C Mississippiensis) sugarberry 



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