PLATE I. 



A. 1 i. FLAX Linum usitatissinmm. x 150. 

 Transverse section of stem. 

 Beginning at periphery : 

 Layer of cuticular cells. 

 Intermediate cortical parenchyma. 

 Bast fibres in groups flax fibres proper. Note secondary 



thickening of cell walls. 

 Cambium region. 

 Wood. 



1 These letters refer to the grouping of the table, page 311. 



