242 



LEGUMINOSAE 



are thus presented to the eye of the traveler in the early part of the rainless season long streamers 

 of bright yellow winding amongst the low hills, bands of color which are in striking contrast to 

 the general graynoss of the desert. 



Locs. — Wagon Wash near Sentenac Canon, e. San Diego Co., Jepson; Yaqui Well, w, Colo- 

 rado Desert, Jcpsnn 12,519; Borrego Spr. ; Santa Rosa Mts. (canons on desert side), Clary 812; 

 Chuckwalla Mts., Schcllcnger ; Beals Well, 11 mi. e. of Niland; Canon Sprs., Hall 5843; Orocopia 

 Mts.: Pleasant Valley, n. of Indio, Jepson; Pinto Basin, nw. of Cottonwood Spr., Jepson; War- 

 rens Well, Parish ; Needles; Sheephole Mts.; Ludlow, Jepson 5500; Barstow, Jepson 4775, 5897; 

 Randsburg; Red Rock Canon; Haloran Spr., e. Mohave Desert, Jepson 15,796; Salt Well, Inyo Co. 



Refs. — Cassia armata Wats. Proc. Am. Acad. 11:136 (1876), type loc. Mohave Desert be- 

 tween Ft. Mohave, Ariz., and Cajon Pass, Cal., Cooper; Jepson, Man. 512, fig. 511 (1925). 

 Xerocassia armata Britt. & Rose, N. Am. Fl. 23:246 (1930). 



2. C. covesii Gray. Bush 1 to 2 feet high ; leaf-rachis short, bearing 3 pairs of 

 leaflets ; leaflets elliptic, 6 to 12 lines long ; racemes few-flowered, corymbose, 1 to 2 

 inches long; petals oblong-obovate, veined, 6 lines long; pods straight or nearly so, 

 1 inch long. 



Sandy washes, 1600 to 1800 feet : Colorado Desert. East to Arizona, south to 

 Lower California. May-June. 



Locs. — Corn Sprs., Chuckwalla Mts., Mum 4' J^ech 4862 ; Martinez Canon, Santa Rosa Mts. 

 (Bull. S. Cal. Acad. 22:9) ; Wagon Wash near Sentenac Canon, e. San Diego Co., Jepson 12,499; 

 Sentenac Valley, Jepson 8779; Box Canon, Mason Valley, Jepson 8665. San Gregorio, L. Cal. 

 (Proc. Cal. Acad. eer. 2, 2:152,-1889). 



Refs. — Cassia covesii Gray, Proc, Am. Acad. 7:399 (1868), type loc. Camp Grant, a. of 

 Prescott, Ariz., Coues, Palmer; Jepson, Man. 512 (1925). 



6. CERCIDIUM Tul. 



Shrubs or small trees, armed with short axillary thorns. Leaves bipinnate 

 with very short petiole bearing one pair of pinnae, each pinna with 2 or 3 equal 

 pairs of leaflets. Flowers on jointed pedicels in 

 axillary racemes. Petals yellow, clawed, the up- 

 per one broader than the rest, a little auricled at 

 base of blade, and with longer claw. Stamens 

 10, distinct, the filaments hairy at base. Pod 

 linear or oblong, flattish. — Species 6, southwest- 

 ern North America and south along the Andes to 

 Chile. (Greek kerkidion, a weaver's shuttle, in 

 reference to the fruit.) 



1. C. torreyanum Sarg. Palo Verde. (Fig. 

 176.) Tree 15 to 20 feet high, with short trunk 

 and smooth green bark, leafless for most of the 

 year; leaflets obovate or elliptic, 2 to 4 lines long; 

 flowers 6 to 9 lines broad; pods II/2 to 4 inches 

 long, often conspicuously constricted between the 

 flat seeds; seeds quadrate, 3 to 5 lines long. 



Sandy washes, sandhills or depressions in the 

 deserts, sometimes on mesas, 100 to 500 feet : Colo- 

 rado Desert. Southern Arizona to Sonora and 

 Lower California. Apr.-May. 



Habit. — A remarkable tree, especially as found in the 

 desert washes, when young often extremely symmetrical, 

 in age with highly irregular or broken crown, it is in 

 either case a striking object in the desert landscape when 

 covered by its drooping flower masses of a fresh and sensi- 

 tive yellow. The long vegetative branches are usually 

 very thorny. The scanty foliage is dropped early or held 

 in whole or in part through the dry season. In either case the bark gives a marked color to the 

 crown which thus makes light-green spots on the arid hills which, along the lower Colorado Eiver, 



h:i 



Fig. 176. 

 ANUM Sarg, 

 &, pod, X 1/2 



Cercidium toeeey- 

 o, fl. branchlet, X % ; 

 ; c, seed, X %. 



