H. Doc. 181. 



PLATE XXII. 



tr.-{ 



l-m.r. 



RADIAL SECTIONS OF PINUS ECHINATA AND HETEROPHYLLA. 



'..parenchyma of same; tr., transverse tracheids of rays; s. p., simple pits; 6. p., bordered 

 1 ; other letters as in A. 



