FURTHER NOTES ON INTERCELLULAR CANALS IN 

 DICOTYLEDONOUS WOODS 



(Contribution from the Yale School of Forestry, No. 11) 



By Samuel J. Record 

 Professor of Forest Products, Yale University 



The identification of woods is purely a matter of elimination. Every- 

 one interested in the subject is on the alert for features and combina- 

 tions of them which will demarcate the smallest possible groups. Two 

 such characters, which have proved very helpful to the writer in nar- 

 rowing the field in the identification of tropical woods, are "ripple 

 marks"' or striations resulting from the storied structure of the ele- 

 ments, and intercellular canals, variously known as resin ducts, gum 

 ducts, gum cysts, gum veins, etc. These ducts are as characteristic 

 of the dipterocarps, for example, as they are of pine and afford one 

 of the most reliable means for distinguishing some of the so-called 

 "mahoganies" from the genuine. 



For several years the writer has been collecting data on the nature 

 and scope of occurrence of these canals and their dependability for 

 diagnostic purposes. They are of two general kinds, vertical or axial 

 and horizontal or radial, the latter being found in the rays. The two 

 kinds are very rarely, if ever, found in the same wood, therein differ- 

 ing from the condition in the ductiferous woods of the conifers. The 

 vertical canals are of two types, the normal, and the traumatic or 

 pathological. The latter are of sporadic occurrence and are, of course, 

 likely to be absent in any given specimen, particularly if it is small. 



The results of the first observations were embodied in a paper ^ pub- 

 lished in 1918. Since then many additional woods have been studied 

 and valuable new sources of information have become available. The 

 present paper consists mainly of notes which have been made from 

 time to time during the past three years. It is hoped that they will 

 stimulate further interest on the part of other investigators. 



Anacardiacecv. — A specimen of "malabog" from the Philippine 

 Islands (Yale No. 2201), Parishia malabog, and two specimens of 



^ Intercellular canals in dicotyledonous woods. Journal of Forestry, 1G :4 :42S 

 441, April, 1918. 



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