April, 1912.] Key to the Fruits of the Genera of Trees. 507 



11. Cone without subulate leaf-scales at the base, cylindric or 



long ovoid, usually 1-G in. long, scales often with erose 

 or emarginatc tips. Picea. 



12. Carpels spirally arranged. 13. 



12. Carpels opposite. 14. 



13. Cone globose, the scales closely compressed on the outside, 



seeds not winged. Taxodium. 



13. Cone ovoid, with subulate leaf-scales at the base, the car- 



pellate scales loose and open; seeds somewhat winged. 



Larix. 



14. Cone oblong or ovoid; the scales not peltate, each with 



2, winged seeds. Thuja. 



14. Cone globular or spherical, the scales peltate. 15. 



15. Carpellate scales with many narrowly-winged seeds. 



Cupressus. 



15. Carpellate scales with 2-3 more or less winged seeds. 



Chamaecyparis. 



16. Fruit globose, over 2 in. in diameter. 17. 



16. Fruit elongated, ovoid or cylindrical. IS. 



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



17. Fruit an aggregate of red drapes projecting beyond the per- 



sistent perianths. Broussonetia. 



18. Fruit very juicy, consisting of a catkin-like aggregate of 



small fleshy flowers. Morus. 

 18. Fruit an aggregate of carpels, the ripe follicles dehiscent, 

 and the seeds pendant from slender threads. Magnolia. 



18. Frait a small blue berry-like cone. Juniperus. 



19. Catkin composed of capsules with numerous seeds having 



tufts of cottony hairs. 20. 



19. Catkin containing 1-seeded nutlets, achenes, or samara-like 



nutlets. 21. 



20. Capsule with a little cup at the base. Populus. 



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



may be present. Salix. 



21. Fruiting catkin with leaf -like bracts; nutlets with ridges, 



somewhat compressed. Carpinus. 



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

 somewhat compressed, ridges inconspicuous. Ostrya. 



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

 pressed, winged or wingless. Alnus. 



21. Fruiting catkin compact with rather thin scale-like bracts, 



cone-like; nutlets compressed, membranous-winged; sa- 

 mara-like. Betula. 



— 22 — 



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



capsule, or a dry drupe. 23. 

 22. Fruit fleshy, indehiscent. 00. 



