A Bud and Twig Key 19 



hs. Pith round, buds broadly ovate, one- 

 fourth inch long light brown glabrous, 

 flattened against twig, twig glabrous light 

 brown. * Morns rubra Linn. 



f4. Buds ovate acute, more than four scales 

 visible. 



gi. Bundle-scars about six to ten scattered, bud 



appressed, not more than five scales visible. 



Morus rubra (see above). 



g2. Bundle-scars three to six arranged in a 

 lunate line. 



In. Pith five-angled, terminal bud ovate long 

 pointed, leaf-scar broad, outermost bud- 

 scale directly above leaf-scar, middle one 

 of the three bundle-scars often double, 

 branchlet roughened by elevated leaf- 

 scars. Populus Linn. 



ii. Terminal bud one-half to three-fourths 

 inch long, resinous. 



//. Buds fragrant very resinous, three- 

 fourths inch long and one-fourth 

 inch broad, lateral buds often flat- 

 tened against twig, twigs stout light 

 or dark orange color lustrous, bud 

 scales slightly pubescent at base, 

 scarious margins. 



P. trichocarpa Torr. & Gr. 



J2. Buds not fragrant, one-half inch 

 long, resinous, flattened, slightly 

 pubescent at base, leaf-scar three- 

 lobed truncate or emarginate above, 

 twigs stout often with ridge extend- 

 ing downward from each side of leaf 

 scar. P. deltoides Marsh. 



Compare Ccltis orcidcntalis. 



