THE OAK. 



Fio 1 ' Transverse section of young stem, showing primary vaseukr 

 bundles, etc., highly magnified. and 6, the pith ; , primary cortex: 

 t', epidermis ; A, peridcnn (cork); ff, collcnchyma. Two complete 

 primary vascular bundles, and parts of two others, are shown, sepa- 

 rated by the primary medullary rays, r, spiral vessels (protoxylem); 

 t, bast-fibers (protophloem) ; , m, cambium, separating the phloem 

 from the xylem; p, wood-parenchyma. Secondary medullary rays 

 urc seen in the bundles, as also are pitted vessels of different sixes. 

 (Th- Hartig.) 



