666 



A TEXTBOOK OF THEORETICAL BOTANY 



I 



pit, which is in striking contrast with the bordered pits that connect the I 

 tracheids with each other. 



The secondary wood is also made up of tracheids which are about 4 mm. 



Cortex 



f 



Cambium 



w:^ V:^ f^^^.i • /. X -^%:*^';^ : f ?■ 





^. ^^ '*'^^ Res/n cano/ 



Fig. 664. — -Finiis syivestris. Transverse section of a 

 branch showing secondary wood containing resin 

 canals. 



)^y\em tracheid 



Ray tracheid 



Medullary ray 



Bordered pit 



Fig. 665. — Finns syivestris. Longitudinal tangential 

 section of the secondan,^ wood showing medullary 

 rays and bordered pits on the radial walls only of 

 the tracheids. 



