PLATE III 



Amelanchier alnifolia (7a, 7b, and 7c*) 



Vessels present, solitary or in pairs; annual ring not initiated 

 by band of large vessels; vessels grade into smaller sizes as 

 the growing season progresses without an abrupt change in 

 size; vessel walls giving a smooth, rounded outline to vessel 

 in cross section; vessel perforation plate simple; axial paren- 

 chyma numerous, diffuse; rays one to two cells in width (rarely 

 three). 



Cercocarpus ledifolius (8a and 8b) 



Vessels present, solitary, in pairs or various aggregates; 

 annual ring not initiated by a band of large vessels; vessels 

 grade into smaller sizes as the growing season progresses 

 without an abrupt change in size; early wood with a few large 

 vessels; vessel size decreases greatly from early to late wood, 

 but spacing of vessels remains similar; perforation plate sim- 

 ple; axial parenchyma absent or sparse and diffuse; rays one 

 or two cells in width (rarely three) . 



