ROSACEAE. 95 



4. 8. laevigata. Schneider, f. 133. 8. media. Schneider, f. 



176. 8. prunifolia. Bosemann, 76; Shirasawa, 247. 8. sali- 

 cifolia. Bosemann, 76; Willkomm, 37, f. 57. 



1. Buds with 2 valvate scales. 2. 



Buds with several exposed scales when mature. 3. 



2. Buds short. S. canescens. 

 Buds long and slender. S. longigemmis. 



3. Buds conical: twigs terete, slender. (1). X S. Vanhouttei. 

 Buds ovoid, or else shrubs low. 4. 



4. Buds often collaterally multiplied. (2). S. prunifolia. 

 Buds solitary. 5. 



5. Twigs glabrous. 6. 

 Twigs pubescent. 10. 



6. Twigs terete. 7. 



Twigs more or less distinctly angled. 8. 



7. Twigs dark: buds elongated. (3). x S. cantoniensis. 

 Twigs bright red-brown. S. corymbosa. 



8. Angles evanescent: rather low and simple. 9. 



Angles pronounced: tall and bushy. S. chamaedryfolia. 



9. Vestiges of inflorescence corymbose. S. betulaefolia. 

 Vestiges of inflorescence paniculate. (4). S. latifolia. 



10. Pubescence gray or merely dingy, usually velvety. 11. 

 Pubescence often rusty and woolly. (5). S. tomentosa. 



11. Twigs more or less distinctly angled. 12. 



Twigs terete: inflorescence corymbose. S. japonica. 



12. Twigs neither excessively slender nor numerous. 13. 

 Twigs filiform. (6). S. Thunbergii. 



13. Inflorescence corymbose. 14. 

 Inflorescence paniculate. 15. 



14. Stems slightly glaucous. S. virginiana pubescens. 

 Stems not glaucous. X s - Bumalda. 



15. Pubescence abundant. S. Douglasii. 

 Pubescence scanty. S. alba. 



