Proceedings of the Ohio State Academy of Science 107 



12. Leaves opposite or whorled. 13. 



12. Leaves alternate. 14. 



13. Trees or shrubs with pinnate leaves and fruit a samara 



with I wing ; or leaves simple and fruit a drupe. Olea- 



CEAE. 



a. Leaves compound ; fruit a samara ; flowers mostly 



dioecious. Fraxinus. (69). 

 a. Leaves simple ; fruit a drupe ; flowers dioecious, 



from catkin-like scaly buds. Adelia. (70). 



13. Fruit a 2-winged, 2-seeded samara; leaves palmately veined 



or if pinnately compound then the petioles covering the 

 axillary buds. Aceraceae. 



* a. Acer. (57). 



14. Base of petiole covering the axillary bud ; the flowers in 



dense spherical heads, the carpellate on a long slender 

 peduncle; twigs with stipular rings. Platanaceae. 



a. Platanus. (31). 



14. Base of petiole not covering the axillary bud, and inflores- 



cence and twigs not as above. 15. 



15. Trees or shrubs with compound punctate leaves. Rutaceae. 



a. Xanthoxylum. (49). 



15, Trees usually with serrate pinnately-veined sometimes palm- 

 ately-veined leaves with fugaceous stipules ; ovulary uni- 

 locular, i-2-ovuled ; fruit a samara, drupe or nut. Ulma- 

 ceae. 

 a. Flowers in clusters on twigs of the previous season ; 

 fruit a samara or nut-like. b. 



a. Flowers on twigs of the season, fruit a drupe. 



Celtis. (25). 



b. Flowers expanding before the leaves ; fruit a 



samara. Ulmus. (23). 

 b. Flowers expanding with the leaves; fruit nut-like. 

 Planera, ( 24 ) . 

 15. Trees with milky sap; stipules fugaceous; fruit aggregate. 

 Moraceae. 



