550 



TREES OF NORTH AMERICA 



Prosopis juliflora, var. velutina, Sarg. 



Leaves 5'-6' long, often fascicled, cinereo-pubescent, with short petioles and 12- 

 22 pairs of oblong or linear-oblong obtuse or acute crowded pale green leaflets \'-^' 

 long. Flowers in densely-flowered spikes 2'-3' long; calyx villose. 





''if 



A tree, often 50 high, with a trunk 2 in diameter, covered with rough dark 

 brown bark, and heavy irregularly arranged usually crooked branches. 

 Distribution. Hot valleys of southern Arizona and Sonora. 



2. Prosopis pubesoens, Benth. Screvr Bean. Screw Pod Mesquite. 



Leaves canescently pubescent, 2'-3' long, with slender petioles ^-f in length, 

 and pinnae l^'-2' long and 10-16-f oliolate ; stipules spinescent, deciduous; leaflets 



5IS^ 



oblong or somewhat falcate, acute, sessile or short-petiolulate, often apiculate, con- 

 spicuously reticulate-veined, ^-f long, ^' wide. Flowers beginning to open in 

 early spring, and produced in successive crops from the axils of minute scarious 

 bracts, in dense or interrupted cylindrical spikes 2'-3' long ; calyx obscurely 5-lobed, 

 pubescent on the outer surface, one third to one fourth as long as the narrow 

 acute petals coated on the inner surface near the apex with thick white tomentum, 



