20 A Bud and Twig Key 



12. Terminal buds about one-fourth inch 



long slightly or not at all resinous. 

 ji. Stipule-scars very faint lines or 

 usually none, bud not resinous, axil- 

 lary buds a'bout one-fourth inch 

 long, terminal bud a little longer, 

 scales slightly pubescent, leaf-scars 

 rounded triangular, twig and bud 

 brown, buds spread wide from twig, 

 not flattened. Plate VI. 



P. grandidentata Michx. 

 J2. Stipule-scars distinct, buds slightly 



resinous. 



ki. Pith orange color, buds broadly 

 ovate, scales slightly pubescent to- 

 wards base, leaf-buds one-fourth 

 inch, flower-buds one-half inch 

 long, bright red brown, twigs light 

 yellowish stout becoming darker in 

 second year rough with large 

 leaf -scars. P. hetcrophylla Linn. 

 1?2. Pith white, buds narrow conical 

 sharp-pointed, scales glabrous 

 shiny, scarious margin, leaf-scars 

 lunate, terminal buds usually about 

 one-fourth inch, lateral buds about 

 one-eighth inch long, twigs and 

 buds red-brown lustrous, outermost 

 bud-scale emarginate, twigs slen- 

 "er. Plate VI. 



P. tremuloides Michx. 



h2. Pith round, terminal bud one-eighth inch 

 long, twig has bitter aromatic taste, leaf- 

 scars lunate five ranked on twig, bundle- 

 scars three, many bud-scales glabrous, 

 first pair lateral, stipule-scars distinct 

 but small. * Prunns serotina Ehrh. 



* Compare Ulryits amcricana and Ulnius racemosa. 



