ELASTIC^ GUMS 



2Si 



much too small to he of iiuy economic KJgnificance. The 

 use of this juice to the plant is not altogether clear; but from 

 the fact that it flows readily from a cut and after a little while 

 hardens upon exposure to the aii-, the conclusion seems war- 

 ranted that it serves in jiart at least as a rearly means (jf 



Fig. 270. — Brazilian Rubl)er-trec (Heuea ouyaaensis. Spurge Familj-, 

 Euphorbiacem) . A, flowering branch. B, part of fiower-fluster. ( ', 

 staminate flower. D, same with calyx removed. E, pistillate flower, 

 with caly.x removed. (Berg and Sclimidt.) — Tree growing 20 m. tail; 

 lea-ves thin: flowers inconspicuous; fruit somewhat fleshy. Native 

 home, J-irazii. 



covering wounds promptly with a waterproof ]5r()tection 

 against agencies of decay. 



One of the most important American sources of awutcJwuc 

 is the Brazilian rubber-tree (Fig. 270). Long before the 

 coming of Europeans the South American Indians made use 



