28 



OF WOOD IN GENERAL. 



part in the transfer of formative material from one part of the 

 stem to another. 



FIG. 19. Transverse section of Oak, photographed direct from nature. 



When we examine the stem of a broad-leaved tree, such as an 

 oak, we find, with the same general exogenous arrangement of 



M 



FIG. 20. Part of transverse section through a branch of Cork Oak (Qv.Ki-cux 

 Suiter), 4 years old. After Le Maout and Decaisne, from The Elements of 

 Botany, by permission of Mr. Francis Darwin and the Syndicate of the 

 Cambridge University Press. 



M, pith ; PC, phloem and cortex; S, cork; ], primary pith-ray, running 

 from pith to cortex ; 2, 3, and 4, secondary pith-rays formed in successive 

 years. 



pith, bark, heart-wood, sap-wood, and annual rings, considerably 

 greater complexity in the variety and grouping of the elements 

 of which the tissues are built up (Fig. 18). The pith presents 



