130 ROSACEAE. 



9. Buds round-ovoid, spreading. P. Mahaleb. 



Buds oblong, appressed, glabrous. P. Padus. 



^10. Buds dull brown, ovoid: scales rough. (3). P. virginiana. 

 Buds clear brown or glossy. 11. 



11. Buds conical, light brown. P. Maackii. 

 Buds ovoid. 12. 



12. Buds small (2X4 mm.), glossy: scales rather fleshy. 



(Wild black cherry). P. serotina. 

 Buds large (3X5-7 mm.). 13. 



13. Buds glossy, ovoid-fusiform. 



(Sweet cherry). (4). P. avium. 

 Buds duller or darker, round-ovoid. 



(Sour cherry). P. Cerasus. 



14. Buds scarcely longer than thick. 15. 

 Buds elongated. 16. 



15. Buds half-covered by the ciliate leaf-cushion, twigs slen- 



der, red. (Southern plum). (5). P. angustifolia. 



Buds protruding: twigs velvety, very spiny. P. spinosa. 



16. Buds broadly .ovoid. 17. 

 Buds ovoid-fusiform. 19. 



17. Buds dark: scales ciliate. (Apricot). P. Armeniaca. 

 Buds light brown, puberulent. (European plums). 18. 



18. Twigs glabrous. P. domestica. 

 Twigs velvety. P. insititia. 



19. Twigs velvety. 20. 

 Twigs glabrous. 21. 



20. Low and spreading: buds velvety. P. maritraia. 

 Tall. P. americana mollis. 



21. Buds velvety: twigs slender. " (7). P. cerasifera. 

 Buds glabrous: twigs stouter or stiff. (Wild plums). 22. 



22. Buds red-brown, short (3-4 mm.). (6). P. americana. 

 Buds black or gray, large (4-5 mm.) and subconical. 



P. nigra. 



