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, lissured, dark brown and scaly. The slender sometimes 

 zizgag, often spiny twigs are velvety, grayish brown to }'cllowish brown. The 

 winter buds are short, bluntish and hair)-. 

 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 cylindric 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, 

 sHghtly flattened, sometimes curved, 10 to 18 

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

 both ends, short-stalked, indehiscent, pale yellow, slightly 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 vaiiety. 



Fig. 491. Arizona Mesquite. 



X. SCREW POD MESQUITE 



GENUS STROMBOCARPA A. GRAY 



Species Strombocarpa odorata (Torrey) A. Gray 



Prosopis odorata Torrey. Prosopis piibescens 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 

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

 of 3 dm. 



The bark is rather thick, hght 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 lo 20 mm. long. The leaves 

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



