. Stipule-scars present, 

 j. Bud-scale only i visible; twigs brittle.. 



>SAUX, p. 34. 



jj. Bud-scales 2 or more; twigs not brittle, 

 k. Bark smooth, close, warty or peeling 

 into papery layers^ but not flaky nor 

 rough-ridged. 



I. Tip of bud appressed; fruit berry- 

 like. CELTIS, p. 131. 



II. Tip of bud not appressed; fruit not 

 berry-like. 



m. Trunk fluted ; catkins not present 

 in winter; lenticels not elongated 

 horizontally ; low tree . or bushy 



shrub CARPINUS, p. 83. 



mm. Trunk not fluted; catkins usually 

 present in winter; lenticels elong- 

 ated horizontally; large trees.... 



BETULA, p. 85. 



kk. Bark flaky or rough-ridged, not warty 

 nor peeling off in papery layers. 



I. Bundle-scars depressed, conspicuous; 

 bark thick, more or less deeply fur- 

 rowed ULMUS, p. 123. 



II. Bundle-scars not depressed, incon- 

 spicuous ; bark thin, broken into nar- 

 row, flattish strips, loose at the ends 

 OSTRYiA, p. 81. 



i. Stipule-scars absent. 



j. Buds silky-pubescent, depressed; twigs 

 stout, clumsy, blunt, with conspicuous 



leaf-scars GYMNOCLADUS, p. 163. 



jj. Buds glabrous, not depressed; twigs slen- 

 der, with inconspicuous leaf-scars, 

 k. Buds l /& inch long, obtuse, somewhat 

 flattened and appressed; pith with red- 

 dish longitudinal streaks 



CERCIS, p. 167. 



kk. Buds y^~y\ inch long, acute, not flat- 

 tened nor appressed; pith without red- 

 dish streaks PRUN'US, p. 153- 



XXX 



