592 TREES OF NORTH AMERICA 



The generic name is in honor of Joachim Bnrscr (1593-1049), a German botanist 

 and physician. 



1. Bursera Siraaruba, Sarg. Gumbo Limbo. West Indian Birch. 



Leaves confined to the ends of the branchlets, 6'-8' long, 4'-8' broad, with long 

 slender petioles, and nsually 5, rarely 3 or 7 leaflets, coriaceous at maturity, oblong- 

 ovate, oblique at the base, contracted at the apex into a long or short point, 2^'-3' long, 

 li'-2' broad, with stout petiolules often ^' long, deciduous in early winter or occa- 

 sionally persistent until the following spring. FloTvers about ^\' in diameter, appear- 

 ing before the leaves or as they unfold, on slender pedicels ^'-^ long, in slender 

 raceme-like panicles, those of the staminate plant 4'-5' long or nearly twice as long 

 as those of the pistillate plant; sepals and petals 5; petals ovate-lanceolate, acute, 

 revolute on the margins, and nearly four times as long as the slender acute calyx-lobes; 



stamens of the staminate flower as long as the petals and in the pistillate flower not 

 more than half as long, with smaller often effete anthers. Fruit in short raceme- 

 like clusters, \'-^' long, 3-angled, with a thick dark red outer coat, separating read- 

 ily into 3 broad ovate valves, and containing 1 or rarely 2 bony triangular nutlets 

 rounded at the base, pointed at the apex, and covered with a thin membranaceous 

 light pink coat; seeds 1 or 2, triangular, rose color, 



A glabrous tree, 50-60 high, with a trunk 21-3 in diameter, massive primary 

 branches spreading nearly at right angles, and stout terete branchlets light gray 

 during their flrst season, becoming reddish brown during the second year, covered 

 with lenticular spots and conspicuously marked by large elevated obcordate yellow 

 leaf-scars. Winter-buds short, rounded, obtuse, with broadly ovate dark red scales 

 slightly scarious on the margins. Bark of the trunk and large branches 1' thick, 

 glandular dotted, separating freely into thin papery bright red-brown scales exposing 

 in falling the dark red-brown or gray inner bark. Wood spongy, very light, ex- 

 ceedingly soft and weak, light brown, with thick sapwood, soon becoming discolored 

 by decay. Pieces of the trunk and large branches set in the ground soon produce 

 roots and grow rapidly into large trees. The aromatic resin obtained by incisions cut 

 in the trunk was formerly used in the treatment of gout, and in the West Indies is 

 manufactured into varnish. An infusion of the leaves is sometimes used in Florida 

 as a substitute for tea. 



