PRACTICAL HINTS 



6. Wood fibres, rays of two kinds ; no pores, but vertical resin- 

 canals. 



7. Wood fibres, rays of two kinds, but no pores (vessels) or 

 resin-canals. 



The first class may be neglected as being rare, but the others 

 are very constant, and the presence or absence of one or more of 

 these tissue-systems may serve as a foundation upon which to 

 build a Key. 



xl 



