78 



PLANT LIFE 



vessels, the wood always contains some com- 

 paratively undifferentiated tissue cells, such 



'J 



(0 



T 



<0 



Fig. 12. Diagram to show the bordered pits and how the 

 tracheids in the wood of a pine are connected with each 

 other. LT, lower tracheid ; UT, UT, two upper tracheids ; 

 BP, bordered pits. At the top a bordered pit is shown 

 in section (very highly magnified). 



as are of common occurrence throughout 

 the plant body; these, from their ordinary 



