BUESERACEAE. 



171 



Bursera. West Indian Birch. 

 (Family Burseraceae). 



Tender resinous trees with pa- 

 pery-flaking red or brown bark 

 and extremely light, soft and ut- 

 terly worthless wood: subdecidu- 

 ous. Twigs glabrous, moderate, 

 terete: pith round, continuous, 

 light brown. Buds solitary, ses- 

 sile, small, depressed globose, with 

 about 3 more or less short-pointed 

 scales. Leaf-scars alternate, half- 

 round, low: bundle-traces 3: sti- 

 pule-scars lacking. Leaves, if 

 present, like the twigs closely re- 

 semble those of mahogany, from 

 which in bark, wood and habit it 

 greatly differs, as it does in the 

 technical characters of flowers and 

 fruit. 



An effective contrast of the bark 

 of Bursera and Swietenia is af- 

 forded in figures 9 and 10 of the 

 text accompanying part 13 of Hough's American Woods, of 

 which thus far 325 species have been distributed in cross sec- 

 tion, and tangential and radial longitudinal sections. 

 Twigs light brown, warty. (Gumbo limbo). B. Simaruba. 



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