THE VASCULAE TISSUES. 



61 



characterised by the presence in their walls of small bordered- 

 pits (for the structure of bordered-pits see pp. 67 and 68 on 



H O +3 



thexylem), and are known as transfusion-cells (see Figs. 41a, 416). 

 The tissue lies outside the bundles, internal to the endodermis,. 

 and its communication with the phloem of each bundle may be 



