Trees of the Northern United States 131 



17 Fruit green or yellowish-green,. 3-5 in. in diameter. 



Toxylon. (52). 



17. Fruit an aggregate of red drupes projecting beyond 



the persistent perianths. Papyrius. (58). 



18. Fruit very jucy. consisting of a catkin-like aggregate 



of small fleshy flowers. Morus. (51). 



18. Fruit an aggregate of carpels, the ripe follicles 



dehiscent, and the seeds pendant from slender 

 threads. Magnolia. (12). 

 \S. Fruit a small blue berry-like cone. Juniperus. (11). 



19. Catkin composed of capsules with numerous seeds having 



tufts of cottony hairs. 20. 

 1!). Catkin containing 1-seeded nutlets, achenes, or samara- 

 like nutlets. 21. 



20. Capsule with a little cup at the base. Populus. (64). 



20. No cup at the base of the capsule but 1 or 2 little 



glands may be present. Salix. (65). 



21. Fruiting catkin wnth leaf-like bracts; nutlets with 



ridges, somewhat compressed. Carpinus. (57). 



21. Fruiting catkin hop-like, with bladder-like bracts; 

 nutlets somewhat compressed, ridges inconspicu- 

 ous. Ostrya. (58). 



21. Fruiting catkin woody and cone-like,- nutlets small 

 compressed, winged or wingless. Alnus. (60). 



21. Fruiting catkin compact with rather thin scale-like 



bracts, cone-like; nutlets compressed, membranous- 

 winged; samara-like. Betula. (5D). 



—22— 



22. Fruit a dry or nearly dry samara, nut, achene. bean, 



or capsule, or a dry drupe. 23. 



22. Fruit fleshy, indehiscent. 55. 



23. Fruit or the peduncle prominently winged. 24. 



23. Fruit and peduncle not with wings. 30. 



24. Peduncle of the fruit cluster with a large wing; fruit 



a dry drupe. Tilia. (20). 



24. Peduncle not winged ; fruit a true samara, or with 1 or 



more prominent wings. 25. 



25. Fruit with a prominent spine-like beak at the lip and 



with 2 or 4 wings, large. Halesia. (72). 

 25. Fruit not with a prominent spine-like point. 26. 



