FIG. IT. Transverse section of cortex and phlegm of oak (highly magni- 

 fied). , the periderm (cork), which has replaced the epidermis ; c, 

 collenchyma ; </, cells of cortex containing crystals of oxalate of lime ; 

 , schlerenchyma cells. All these belong to the cortex proper. Be- 

 low these come the phloem : 5, J, groups of hard bast fibers ; bp, 

 phloem-parenchyma ; Js, medullary ray ; e, cells containing crystals 

 of oxalate of lime. (Luerssen.) 



