Proceedings of the Ohio State Academy of Science 93 



i6. Leaf scar not surrounding the axillary bud, terminal 

 bud not self-pruned ; buds enclosed in the large con- 

 nate stipules. 17. 



17. Buds glabrous; twigs brown; pith diaphragmed ; leaf 

 scars oval or circular ; bark spicy-aromatic. 



Liriodendron. (33)- 



17. Buds downy, or if glabrous then the twigs red ; pith 



with or without diaphragms ; leaf scars U-shaped, oval, 

 or circular; bark usually aromatic. Magnolia. (32). 



18. With thorns, prickles, or spines ; or with spur-like 



branches ending in thorns. 19. 



18. Without thorns, prickles or spines, but some may have 



thorn-like stunted branches. 26. 



19. W^th stipular spines, a pair for each leaf scar. 20. 



19. Twigs with typical lateral thorns, without terminal 



thorns. 21. 

 19. AMth thorns at the ends of branches or with spur-like 



branches ending in thorns, and in addition axillary 



thorns may be present. 22. 



19. Stems or twigs with prickles; leaf scar extending nearly 



arotuul the stern, with about 20 bundle scars; pith 

 large. Aralia. (74). 



20. Leaf scar covering the two or more superposed axillary 



buds. Robinia. (48). 



20. Leaf scar below the axillary buds; buds reddish, pubes- 



cent. Xanthoxylum. (49). 



21. \\'^ith thorns beside the axillary buds; normally one for 



each leaf axil, becoming gradually smaller toward the 

 tip of the twig, terminal bud absent. Toxylon. (27). 



21. Thorns axillary, large, rarely branched except on the 

 main trunk; usually with two lateral buds at the base 

 which may develop as twigs ; numerous axils without 

 thorns. Crataegus. (41). 



21. Thorns commonly branched, situated above the axil of 

 the leaf ; leaf scar covering the two or more super- 

 posed axilLary buds ; twigs polished, often zigzag. 



Gleditsia. (45). 



