A Bud and Twig Key 



bj. Twigs without thorns or prickles. 



ci. Pith salmon colored, twigs very large, buds small two 

 superposed covered with brown hairs, no terminal 

 bud, tip-scar prominent, no stipule-scars, leaf-scar 

 large shield-shaped with three to five large protruding 

 bundle-scars in a U-line, twig reddish brown or light 

 gray. Plate II. 



Gytnnocladns dioicus (Linn.) Koch. 

 C2. Pith white to yellow. 



di. Twigs very large, bundle-scars six to eight. 



ei. Pith large cream color, twig greenish brown 



smooth with slight bloom, bud reddish silky half 



surrounded by large shield-shaped leaf-scar, no 



terminal bud, tip-scar prominent, no stipule-scars. 



Ailanthus glandulosa Desf. 



e2. Pith large yellow, twig hairy, bud densely silky 

 grayish nearly surrounded by U-shaped leaf-sear, 

 juice milky resinous, no stipule-scars, no term- 

 inal bud, tip-scar or dead tip of twig prominent. 

 Plate II. *Rhus hirta (Linn.) Sudworth. 



d2. Twigs small and glabrous, bundle-scars three or 

 rarely five. 



ei. One bud in axil of each leaf, only white silky 

 top visible, nearly surrounded by U-shaped leaf- 

 scar, no stipule-scars, no terminal bud, tip-scar 

 prominent, twig dark red brown. Plate II. 



Ptelea trifoliata Linn. 



e2. Several superposed buds in axil of each leaf, 

 glabrous, hidden beneath leaf-scar; twig light 

 yellow brown, glabrous. 



Gleditsia triacanthos (see above, page 7). 



0,2. Bud at end of twig not sunk in bark. 



bi. Bud at end of twig irregular in outline, unsymmetrical 

 in form, scales felty. 



* Rhus glabra differs from Rhus hirta only in having smooth instead 

 of densely hairy twigs. 



