LEGUMINOS.E 



599 



short-petiolulate, pale bright green, l'-\' long. Flowers sessile, fragrant, in heads |' in 

 diameter, appearing in succession as the branches grow from early spring to midsummer, 

 on slender peduncles l'-l|' long and fascicled in the axils of upper leaves; calyx one 

 fourth as long as the acute petals and like them pilose on the outer surface; stamens twice 

 as long as the petals; ovary coated with long pale hairs. Fruit conspicuously thick- 

 margined, 4 '-14' long, long-stalked, tipped with a short straight or recurved point, usually 

 in pairs on a peduncle thickened at apex; seeds T 5 (T ' long. 



A tree, 50-60 high, with a straight trunk 18'-20' in diameter, separating 20-30 

 from the ground into slender spreading branches forming a loose round head, and branch- 

 lets at first more or less striately grooved and thickly coated with pulverulent caducous 

 tomentum, becoming at the end of a few weeks terete, pale cinnamon-brown and puberu- 

 lous. Bark about }' thick, bright cinnamon-brown, and roughened by thick persistent 



Fig. 549 



scales. Wood heavy, hard, very close-grained, rich dark brown, with thin clear yellow 

 sap wood of 2 or 3 layers of annual growth; considered valuable, and sometimes manufac- 

 tured into lumber. 



Distribution. Rich moist soil of river banks and the borders of lagoons and small 

 streams; valley of the lower Rio Grande; in Texas only for a few miles near its mouth; 

 more abundant from Matamoras to Monterey in Nuevo Leon; and southward to the 

 neighborhood of the City of Mexico. 



Occasionally planted as a shade and ornamental tree in the towns of the lower Rio 

 Grande valley and in New Orleans, Louisiana. 



5. PROSOPIS L. Mesquite. 







Trees or shrubs, with branches without a terminal bud and armed with geminate supra- 

 axillary persistent spines, and small obtuse axillary buds covered with acute apiculate 

 dark brown scales. Leaves alternate on branches of the year and fascicled in earlier 

 axils, deciduous, usually 2 rarely 3-4-pinnate, with many-foliolate pinnae; petioles 

 glandular at apex with a minute gland, and tipped with the small spinescent rachis; 

 stipules linear, membranaceous or spinescent, deciduous. Flowers greenish white, nearly 

 sessile, in axillary pedunculate spikes; calyx campanulate, 5-toothed, or slightly 5-lobed, 

 deciduous; petals 5, connate below the middle or ultimately free, glabrous or tomentose 

 on the inner surface toward the apex, sometimes puberulous on the outer surface; stamens 

 10, free, inserted with the petals on the margin of a minute disk adnate to the calyx-tube, 

 those opposite the lobes of the calyx rather longer than the others; filaments filiform; an- 

 thers oblong, versatile, their connective tipped with a minute deciduous gland, the cells 



