436 JOURNAL OF FORESTRY 



malwgany and of Cedrela sp. In Cedrela they are rather large and 

 conspicuous, arranged in close tangential series with the usual anas- 

 tomes, and filled with dark-red gum. They are evidently lysigenous — 

 at least in the later stage of their development. In Swietenia the ducts 

 are smaller and less conspicuous because of the contents being amber- 

 colored. They are frequently in a double row. 



Resin cavities are said to arise in Carapa guianensis through disor- 

 ganization of groups of cells (2, p. iioi ; 4, p. 197). 



Anacardiacece 



Trecul (3) found in Rhus viminaUs that branches of the resin canals 

 in the bast penetrated the medullary rays of the wood, and ended 

 blindly. The present writer has found no other reference to secretory 

 canals in the woods of this family, but has observed vertical canals only 

 in Drimycarpus racemosa and radial canals only in the following: As- 

 tronium sp., Buchanania latifolia, Garuya ahilo, Gluta tavoyana, Kood- 

 ersiodendron pinnatum, Odina zvodier, Rhus laiirina, R. metopium, R. 

 rhododanthema, Schinopsis lorentsii, S. halansce, Schinns ivienmanm- 

 folins, Spoiidias mangifera, S. lutea, Tapirira sp. 



Bombace(r 



Vertical traumat*ic ducts have been noted by the writer in a specimen 

 of wood of Pachira sp. from Colombia. In size, appearance, and ar- 

 rangement these canals closely resemble those in Cedrela. 



Dipterocarpacecu 



The writer has observed vertical canals in various representatives of 

 this family, but radial canals are apparently absent. Vertical canals are 

 said to be present in all genera except Lophira, Ancistrocladus, and 

 Monetes. The interxylary resin ducts ard mostly surrounded by wood 

 parenchyma, but sometimes by prosenchyma, and they are often ar- 

 ranged in concentric circles. They may not appear until late in the sec- 

 ondary growth of the wood, and may become filled with tyloses. They 

 have been reported upon by various writers, among whom may be men- 

 tioned Van Tieghem (10). Guerin (11), and Solereder (2, pp. 139-40; 

 840-1). 



In addition to the vertical ducts normally present, others may be 

 induced to form, as in Piiius, by wounding, as demonstrated by Tschirch 

 (4. pp. 1203-4). 



Schneider (12, p. 162) says: "The most characteristic feature of the 

 family is the presence of numerous resin ducts, partly scattered, but 



