Screw Pod Mesquite 



531 



tree, with numerous irregular thick and crooked branches, attaining a height of 

 15 meters, and a trunk diameter of 6 dm. 



The bark is rough, fissured, dark brown and scaly. The slender sometimes 

 zizgag, often spiny twigs are velvety, grayish brown to yellowish brown. The 

 winter buds are short, bluntish and hairy. 

 The leaves, which are often clustered, are 

 evenly bipinnate, with i, or often 2, pairs of 

 pinnae, on very hairy stalks 4 to 6 cm. long 

 and terminated by a small spine between the 

 bases of the end pinnae; the pinnae are hairy- 

 stalked with 12 to 20 pairs of leaflets, which 

 are oblong or linear-oblong, 7 to 10 mm. long, 

 blunt or pointed, leathery, light green, promi- 

 nently veined and persistently hairy or becom- 

 ing smooth. The flowers are in i to 3, 

 clustered axillary dense cyhndric spikes 5 to 

 7.5 cm. long, on stout, hairy peduncles about 

 2 cm. long; the bell-shaped calyx, with trian- 

 gular lobes, is very velvety; petals 5, oblong, 

 blunt-pointed and hairy on the inner surface; 

 stamens 10, distinct and exserted ; ovary nearly 

 sessile and very hairy. The fruit is linear, 

 slightly flattened, sometimes curved, 10 to 18 ^'''- 49i-- Arizona Mesquite. 



cm. long, 8 mm. wide, somewhat constricted between the seeds, abruptly pointed at 

 both ends, short-stalked, indehiscent, pale yellow, shghtly veined lengthwise, vel- 

 vety when young, somewhat hairy when ripe. 



The wood and fruit are put to the same uses as those of the preceding species, 

 of which this tree is often regarded as a variety. 



X. SCREW POD MESQUITE 



GENUS STROMBOOARPA A. GRAY 



Species Strombocaipa odorata (Torrey) A. Gray 



Prosopis odorata Torrey. Prosopis pubescens Bentham 



HIS small tree or shrub is also called Tomillo, and Screw bean. It is 

 common in sandy or gravelly bottom lands, from western Texas to 

 California; its maximum height is 10.5 meters, with a trunk diameter 

 of 3 dm. 



The bark is rather thick, Ught brown, and separates into long thin shaggy 

 flakes; the twigs are round, finely hairy at first, becoming smooth, light reddish 

 brown; they are armed with stiff stipular spines 8 to 20 mm. long. The leaves 

 are deciduous, evenly bipinnate, usually with i pair of pinnae, sometimes 2 pairs. 



