28o ULMACEAE 



1. Ulmus [Tourn.] L. 



At least some of the branches corky winged; samara faces pubescent. I. U. Thomasi. 

 None of the branches winged. 



Leaves smooth or somewhat roughened above; samara faces 



glabrous, the margins ciliate. 2. U. americana. 



Leaves very rough above; samara faces pubescent over the seed, 



the margins not ciliate. 3. U.fuha. 



1. U. Thomasi Sargent ( U. racemosa Thomas). On hillsides and 



slopes: Que. and Ont. to Mich, and Wise, south to N. J., Ky., 

 Ohio, Mo. and E. Neb. 



Known in our range only from Woodruff's Gap, Sussex Co., 

 N.J. 



2. U. americana L. In various situations: Newf. to Fla., west 



to Sask., S. Dak., south to Kan. and Tex. 



Throughout the range except in the pine-barrens of N. J. and 

 east and south of them; not known as a wild tree on L. I. 



3. U. fulva Michx. Rocky hillsides and banks of streams: Que. 



to Fla., west to N. Dak., Neb. and Tex. 



Conn. Local over most of the state, increasing northward. 



N. Y. Frequent north of the moraine on L. I.; S. I., thence in- 

 creasing and common northward, particularly in the Catskills. 



N. J. Burlington, Mercer and Monmouth counties, north and west 

 of the pine-barrens, rare; thence increasing and common north- 

 ward. 



Pa. Monroe, Northampton, Delaware and Chester counties, 

 presumably in the intervening territory. 

 Tertiary, o: Cretaceous, rare and local. Older Formations, 



common northward. 117-204 days. Sea level-1,933 ft. 



The English elm, Ulmus campestris L., and the wahoo, U. alata Michx., have both 

 been reported as established escapes. 



2. Celtis [Tourn.] L. 



Pedicels long, mostly twice as long as the drupe or longer. 

 Leaves smooth or nearly so above. 



Leaves acute or short acuminate. I. C. occidental is. 



Leaves long-acuminate. 2. C. canina. 



Leaves rough above; drupe subglobose. 3. C. crussifolia. 



Pedicels short, less than twice as long as the drupe. 4. C. georgiana. 



i. C. occidentalis L. In rocky places, often on hillsides; Que. to 

 N. Car., westward to Man., Neb. and Okl. 



Throughout the range but not very common, decreasing in the 

 pine-barrens of L. I. and wanting in those of N. J. 



