CELL-CONTENTS AND FORMS OF CELLS. 293 



-r, o T^ 1 ^^„f r.( rnrlf A in eoidermal cells of stem of Oleander; B, 



cork cells.— After Dippel in "Das Mikroskop.' 



BoRK —The cork cambium or phellogen develops before ma- 

 turity in the green stems of woody plants belonging to the dico- 

 tyledons. It mav develop in the primary or secondary tissues 



