556 



The Locusts 



The slender branches are spreading, forming a roundish head. The bark is 

 about 3 mm. thick, roughish and dark gray or brown. , The twigs are viscid, red- 

 dish brown and covered with glandular hairs. The leaves are 1.5 to 3 dm. long, 

 consisting of 11 to 27 leaflets and a stout nearly round petiole which is often 

 glandular and viscid, and slightly enlarged at the base; the leaflets are rather thick 

 and firm, ovate, oblong or elliptic, 2.5 to 4 cm. long, rounded or pointed and 

 bristle tipped at the apex, rounded or tapering at the short-stalked base, entire 

 on the margin, dark green and smooth above, pale and somewhat hairy, especially 

 along the yellowish venation beneath; the stipules are slender, rarely developing 

 into slender spines. The flowers, appearing in May and June and often again 

 in the autumn, are odorless, in dense racemes 5 to 8 cm. long; the slender pedun- 

 cle and pedicels are covered with long glandular hairs. The calyx is red • and 

 hairy, its lobes awl-shaped; the corolla is pink or flesh colored; the standard narrow 

 and marked with yellow blotches; the wing petals are broad. The fruit is linear, 

 flat, 5 to 10 cm. long, somewhat glandular, hispid and viscid, sunken between the 

 seeds, tapering at each end and tipped with the remnants of the style; seeds about 

 4 mm. long, reddish brown, mottled. 



The wood is hard, close-grained and brownish; its specific gravity is about 0.81. 



It is well known in cultivation as a handsome flowering tree; there are several 

 varieties, some of which are probably hybrids with the common locust. 



3. NEW MEXICO LOCUST — Robinia neo-mexicana A. Gray 



A small tree of mountain sides near 

 streams in New Mexico, Arizona and 

 southern Colorado, at altitudes of 1200 to 

 3000 meters. It attains a height of 7.5 

 meters, with a trunk diameter of 3.5 dm. 

 in Colorado, but is usually a shrub and 

 commonly called Locust. 



The trunk has a thin, nearly smooth 



bark of a light brown color, breaking into 



small scales. The twigs are covered with 



brown glandular hairs which persist for at 



least one season, after which they become 



reddish brown and often glaucous. The 



leaves are 1.5 to 3 dm. long, consisting of 



13 to 21 leaflets and a stout hairy petiole 



which is grooved on the upper side. The 



_7 y Z' ^s^ leaflets are thin, oblong to ovate, about 4 



Fig. 514. — New Mexico Locust. cm. long, roimded, sometimes notched and 



bristle-pointed, wedge-shaped or rounded at the base, entire on the margin, hairy 



when unfolding, soon becoming smooth and bluish green above, paler with con- 



