Tkkks ok thk Xorthkkn United States 91 



I he largest trunks usually hollow, sometimes as much as il 

 tl. in circumference. Autumn leaves brown. Wood rather 

 hard, compact, coarse-grained, difficult to split, toug'h, and of 

 a light-brown color; used for tobacco boxes, cooperage, cab- 

 inet-work, and finishing lumber. Along the banks of streams 

 and in moist ground imt grow\s well in ordinary mesophytic 

 conditions. Me. to Ont. and Minn.. Fla., Kan. and Tex. 



■_'. i'ldldinis oricntalis L. Oriental Planetree. A large 

 tree much like the preceding, but usually with a comparatively 

 shiu't, massixe lrun]< and a broad round cmwn. Lea\'es more 

 cut and becoming smooth earlier. ( )ccasionall\ planted. 

 I'rom Western .\sia and J^!astern Europe. 



Order. L'rtkai.ks. 



/ luuiccac. Elm j-amily. 



4S. Ulmus ('iOurn.) L. Elm. 



Trees with alternate, 2-ranked, pinnately straight-veined. 

 ine(]uilateral, doubly serrate leaves and sessile axillary buds. 



l-'lowers bisporangiate or imperfectl>' bisporangiate. in 

 clusters or racemes: fruit a samara; trees of rapid growth. 



1. Leaves very rough al)ove ; twigs not corky-winged 

 and not self-pruned, but large numbers of lateral 

 I)uds cut ofif: inner l)ark sometimes mucilagious. 2. 



1. Lea\es smooth or sometimes somewhat rough 

 ab,;ve. :J. 



1. Imier bark \ery nnicilaginous. l)uds rusty-downy, 

 samara much Ic.ss than I in. long. / . Iiiii'n. 



■_'. Inner bark not nnicilaginous, buds not do\\n\, .samaras 

 I in. lung. r. iiiontana. 



■'!. Xi'ue of the branches corky-winged; twigs smooth. 

 self-i)runed by basal joints and by cleavage planes 

 in the nodes of anmial growth ; samara faces 

 gIa])rous. U. amcricana. 



■ t. .\dne of the branches with corky ridges; twigs glab- 

 rous or nearly so, not self-pruned; samara glab- 

 rous or nearly so, deeply notched. l\ camf^csiris. 

 1. .Soim- or all of the branches corky-winged, or twigs 

 pnlxrnlent. scIf-pruned: s.amara- faces pubescent. 1. 



