PLATE 3. EXOGENOUS STRUCTURE IN WOOD. 

 Medullary or Pith Ray. 



T 



'W«l!«il.V(M, 



iPii'iii iiiiii.i, 



iiiiiiiii.; ! Iiiii i 



Artii:il api""-:iranCL-'S of pith ray, PP. 







WW 



iia 



:4S 



Microscopic c-nlargcment of a tangential section of Wlilte Oak 

 sliuwing large pith ray, pji. 



