172 



ground forests'^— and furuislies a cheap and valuable fael. The tim- 

 ber is heavy, very hard, and possesses remarkable durability. It is 

 employed chiefly for fuel, tie-timber, and fencing, but somewhat for 

 heavy wheel stock and in the manufacture of charcoal. 



Descrijytion. — Leaves compound, twice iiinuate, single or in clusters, with a pair of 

 stiff, straight, yellowish thorns i to i inch long at the base of each leaf stalk or 

 cluster : leaflets J to If inches long, by ^^ to I of an inch wide, elliptic-ohlong to lance- 

 linear. A cup-shaped gland at the end of the main leaf-stem, (where the usually 

 single pair of smaller stems (pinnne) with leaflets is given off). Pods somewhat flat- 

 tened, straigbtish or curved, 3 to 7^ inches long, J to -I an inch wide ; composed of 12 

 to 25 lobe-like joints (containing as many seeds), and terminating in an awl-point ; 

 young pods covered with a dense velvety down, yellowish-white when mature. They 

 have a sweet taste, and are often used for fodder. 



40. — Screw Bean. Sorew-pod. Mesquit. Tornilla. {Prosopis 



pudescens, Benth.) 



A small tree or shrub growing on gravelly or sandy bottom-land, 

 through 'New Mexico (in western Texas, through Arizona to California; 

 southward into Mexico) ; said to attain its largest size within the 

 United States in the valleys of the lower Colorado and Gila Elvers — 

 20 to 25 feet in height, and 6 to 12 inches in diameter. The wood is 

 heavy, very hard, and brittle, but exceedingly dui^ble, and is used for 

 fencing and fuel. Pods sweet, sometimes used for fodder, and for flour 

 by Indians. 



Description. — Leaves essentially as in Prosopis juliflora (No. 39), Avith a pair of 

 straight pearly- white thorns at base of each leaf or cluster; leaflets elliptic-oblong, 

 often with a short fine point (probably less variable in size than those of the preced- 

 ing species), i to ^ an inch long, and -jV to -J- of an inch wide. Pods cylindrical, 1 

 to 2^ inches long, ^ to i of an inch in diameter, straightish or crooked, closely coiled 

 in a spiral; clothed with a fine velvety down ; light brown at maturity. Branchlets 

 with white longitudinal (decurreut) lines proceeding from the bases of the thorns. 



41. — Cat's Claw. {Acacia Greggii, Gray.) 



Often a shrub, or a low much-branched tree, 20 to 25 feet in height and 

 sometimes 10 inches in diameter, growing abundantly on the dry table- 

 lands and in the low canyons of southern Utah (Dr. Palmer), ^e^w Mex- 

 ico and Arizona (extending to California j also in northern Mexico and 

 western Texas). The wood is heavy, very hard and strong, furnishing 

 good fuel. Large trees often hollow. 



Descrijytioti.— 'Leaf-stems short, giving oif 2 to 3 pairs of smaller stems (pinna?) which 

 bear 3 to G pairs of very small (i to ^ of an inch long) oblong-ovate (broader above) 

 unequal-sided leaflets, with a rounded or abrupt apex, downy. Pods smooth, flat, 

 curved, 3 to 6 inches long, and ^ to f of an inch broad; usually with constrictions 

 between the seeds; the latter flat, obicular, and dark brown. Branches sparingly 

 armed with short hooked prickles, or occasionally unarmed, sometimes with whitish 

 lines. 



