530 



The Mesquites 



bush or a mere straggling shrub; the large tap root is remarkable for the great 

 depth to which it will extend for water in arid soils. It is found from Kansas to 

 Nevada, Texas and California, and southward into Mexico. Its maximum height 

 is about ID meters, with a trunk diameter of 4 dm. This species has been con- 

 fused with the Jamaican Prosopis jidiflora (Swartz) de Candolle, which forms of 

 it much resemble. 



The bark is rather thick, shallowly fissured, with thick, reddish brown scales. 



The twigs are smooth or nearly so, yellowish 

 green, becoming darker, mostly zigzag, and 

 usually spiny. The winter buds are short and 

 blunt. The leaves are evenly bipinnate with 

 I pair of pinnae (rarely 2), with round stalks 

 5 to 10 cm, long, thickened and glandular at 

 the base, with a small gland and spine at the 

 junction of the pinnae; these are 7 to 14 cm. 

 long, with short stalks; they have 6 to 25 rela- 

 tively close or widely separated pairs of leaf- 

 lets, which are linear or nearly so, 1.5 to 4 cm. 

 long, blunt or sharp-pointed, leathery and 

 bright green. The fragrant flowers appear 

 from April until August, in cyhndric spikes 4 

 to 8 cm. long, on slender nearly smooth pe- 

 duncles 5 to ID mm. long; calyx short- 

 stalked, bell-shaped, i mm. long, smooth, 5-lobed; corolla of 5 nearly erect, Unear, 

 sharp-pointed petals, 4 to 5 times the length of the calyx; stamens 10, nearly twice 

 the length of the petals; ovary short-stalked and hairy. The pod is linear, round 

 or nearly so when ripe, i to 2 dm. long, about i cm. thick, straight or nearly so, 

 constricted between the seeds, abiaiptly contracted at each end and short-stalked, 

 yellow, longitudinally veined, the thin outer coat enclosing a sweet pulp, which sur- 

 rounds the obHquely transverse seeds, which are enclosed in thin sacs; seeds flat- 

 tened, oblong, light brown and shining. 



The wood is rather weak, hard, close-grained, dark red to brown, with yellow 

 sapwood, its specific gravity about 0.76. It is much used and highly esteemed for 

 fence posts and paving blocks, and appHed to various other local uses, valued for 

 fuel, and often made into charcoal. The wood of the root, which is often dug up 

 for fuel, is much heavier, having a specific gravity of about 0.84. 



The ripe pods are an important article of food for both man and beast in the 

 desert regions. 



Fig. 490. Mesquite. 



2. ARIZONA MESQUITE Prosopis velutina Wooton 



This, the largest of the Mesquites, occurs in the hot dry valleys of the desert 

 region of southern Arizona, southern Cahfomia and Sonora, often becoming a 



