PLATE XXVI.— TANGENTIAL SECTIONS. 



J-C and F, Pi.vr.s iiKTi;K(iriiYi.i..v. D, Pinus echisata. E, Pinus glauka. 

 A--C, sections of medullary rays; tr., tracbeids; ]>., parenchyma; C is a "double" ray. 



In D-F, histological details are omitted; they are camera drawings showing number and distributicm of nicduUary 

 rays, and also the jiroportiou of the tracheids to parenchyma in each ray, the former being indicated by dots; 

 r. (I., transverse resin ducts; m. r., meiluUary rays, 

 Magnilii-atiou of originals: A-C, '■^'l" ; D-F,^; of illustrations : A-C, ii','" ; D~F, ^. 

 1.54 



