III.] THE CLASSIFICATION OF TIMBERS 45 



trees. Examples of timbers which show no annual 

 rings on the transverse section are common among 

 Indian timbers, eg, iron wood, mango, ebony, &c. 

 In the vast majority of common timbers, however, 

 including many tropical forms, the transverse section 

 always shows more or less concentric zones or rings : in 

 many cases, as in oak, ash, teak, toon, &c., these are 

 obviously the " annual rings," but in other cases, as in 

 the figs, Casuarinay Pongamia, &c. the apparent rings 

 are found to be of a different character, and due to 

 concentric or excentric partial or complete zones of 

 soft tissues, especially wood-parenchyma. I shall term 

 these " false rings : '* a little practice will enable the 

 student to recognise them in most cases. It may be 

 noted that in Calophyllum, and many Sapotaceca and 

 AnonacecBy and others, these partial zones are made up 

 of wavy, pale, bar-like markings between the 

 medullary rays. 



As to the timbers with undoubted rings, two chief 

 types may be readily distinguished if the student 

 understands the meaning of the line of demarcation 

 between the annual rings 



In the one type the vessels in the spring-wood are 

 so large or so numerous (or both), as contrasted with 

 those in the autumn-wood of the same annual ring, 

 that the boundary between any two rings is par- 



