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ULMACEAE. 



ULMUS. Elm. 

 (Family Ulmaceae). 



Trees, usually of large size: de- 

 ciduous. Twigs rather slender, 

 zig-zag, terete: pith small, round- 

 ed, continuous! Buds solitary or 

 collaterally branching, variously 

 ovoid, obliquely sessile, the termi- 

 nal lacking: scales about half-a- 

 dozen, 2-ranked. Leaf-scars alter- 

 nate, 2-ranked, broadly crescent- 

 shaped or half round, scarcely 

 raised: bundle-traces 3 or com- 

 pounded in 3 usually distinct 

 groups: stipule-scars unequal. 

 References under Aphananthe. 



1. Buds small (1.5 mm.), globose: 



scales 4. (1). U. pumila. 



Buds distinctly larger or with 

 more visible scales. 2 



2. Twigs gray-buff, rough: buds 



red-hairy. (2). U. fulva. 



Twigs red-brown, or gray. 3. 

 Buds blackish-red. 4. 

 Buds brown. 7. 



Buds and twigs glabrous. U. laevis. 



Buds more or less hairy. 5. 

 Twigs glabrescent: bark rough. 6. 



Twigs hispid: bark of branches smooth. (3). U. glabra. 



Twigs not corky." U. campestris. 



Twigs often with corky ridges. 

 Twigs moderately slender. 8. 

 Twigs very slender, often corky-winged. 

 Twigs not corky. (White elm). 

 Twigs often with corky outgrowths. 



U. campestris suberosa. 



(4). U. alata. 



U. americana. 



(5). U, racemosa. 



