ROWI.es : SYNOPSIS OF THE GKNUS OCHROMA 157 



times be useful to distinguish the different types. Even though 

 none of the prefixes proposed be thought worthy of general 

 adoption by crystallographers, it is hoped that the desirability 

 of some method of distinction of the several types will not be 

 forgotten, and that in future descriptions of mimetic crystals it 

 will rarely be considered sufficient to refer to them only by the 

 prefix "pseudo." 



BQT ANY .—Syiwpsis of the genus Ochroma, with descriptions of 

 new species. W. W. RowivEE, Cornell University. (Com- 

 municated by Frederick V. Covillc.) 



The utilization of the wood of Ochroma has brought that 

 genus into prominence during the last few years. The manu- 

 facture of buoyancy and insulation products, such as life rafts, 

 refrigerators, and parts of lifeboats and aeroplanes, especially in 

 connection with the war, has become very extensive. Eighty 

 thousand floats made of balsa wood were used in constructing 

 the 250-mile submarine mine barrage in the North Sea; war 

 vessels as well as transports were in so far as possible equipped 

 with balsa life rafts and lifeboats; and special refrigerating trucks 

 with balsa as the insulating material were used in France. The 

 characteristics of the wood were investigated by the late Pro- 

 fessor R. C. Carpenter in a very thorough manner and the re- 

 sults were published in a paper entitled The properties of balsa 

 wood^ The importance of obtaining first-hand information re- 

 garding the quantity of wood available, and of discriminating 

 between the usable and unusable wood, led the American Balsa 

 Corporation to commission the writer and his son in April, 191 8, 

 to explore Central America with a view to finding out the amount 

 of timber available and to investigate as to the quality of the 

 wood and the kinds that grow in different regions. For this 

 purpose we spent seven months in Panama, Costa Rica, Nica- 

 ragua, and Guatemala. The taxonomic results of the survey 

 are given briefly in this paper. 



The wood of the trees of the genus Ochroma is the most notable 

 among lightweight woods. It is generally known in vSpanish 



* Trans. Amer. Soc. Civ. Eng. 81: 125. 1917. 



