LEGUMINOS^ 551 



and slightly puberulous on the outer surface; ovary and young fruit hoary-tomen- 

 tose. Fruit ripening throughout the summer and falling in the autumn, in dense 

 racemes, sessile, twisted with from 12-20 turns into a narrow straight spiral l'-2' 

 long; seeds -^q' long. 



A tree, 25-30 high, with a slender trunk sometimes a foot in diameter, and 

 terete branches canescently pubescent or glabrate when they first appear, becoming 

 glabrous and light red-brown in their third year, and armed with stout spines ^'-^' 

 long. Bark of the trunk thick, light brown tinged with red, separating in long 

 thin persistent ribbon-like scales. Wood heavy, exceedingly hard, close-grained, 

 not strong, light brown, with thin lighter colored sapwood of 6 or 7 layers of annual 

 growth; used as fuel and occasionally for fencing. The sweet, nutritious legumes 

 are used for fodder. 



Distribution. Sandy or gravelly bottom-lands; valley of the Rio Grande in 



western Texas, and through New Mexico and Arizona to southern Utah and Nevada, 



and to San Diego County, California, and northern Mexico; attaining its largest 



size in the United States in the valleys of the lower Colorado and Gila rivers, 



Arizona. 



6. CERCIS, L. 



Trees or shrubs, with scaly bark, slender unarmed branchlets prolonged by an 

 upper axillary bud, marked by numerous minute pale lenticels, and in their first 

 winter by small elevated horizontal leaf-scars showing the ends of two large fibro- 

 vascular bundles, and small scaly obtuse axillary buds covered by imbricated ovate 

 chestnut-brown scales. Leaves simple, entire, 5-7-nerved, with prominent nerves, 

 long-petiolate, deciduous; their petioles slender, terete, abruptly enlarged at the 

 apex; stipules ovate, acute, small, membranaceous, caducous. Flowers appearing 

 in early spring before or with the leaves on thin jointed pedicels, in simple fascicles 

 or racemose clusters produced on branches of the previous or earlier years, or on 

 the trunk, with small scale-like bracts often imbricated at the base of the inflores- 

 cence, and minute bractlets; calyx disciferous, shortly turbinate, purplish, persistent, 

 the tube oblique at the base, campanulate, enlarged on the lower side, 5-toothed, 

 the short broad teeth imbricated in the bud; corolla subpapilionaceous ; petals 

 nearly equal, rose color, oblong-ovate, rounded at the apex, unguiculate, slightly 

 auricled on one side of the base of the blade, the upper one slightly smaller and 

 inclosed in the bud by the wings encircled by the broader slightly imbricated keel- 

 petals; stamens 10, inserted in 2 rows on the margin of the thin disk, free, decli- 

 nate, those of the inner row opposite the petals and rather shorter than the others; 

 filaments enlarged and pilose below the middle, persistent until the fruit is grown; 

 anthers uniform, oblong, attached on the back near the base; ovary short-stalked, 

 inserted obliquely in the bottom of the calyx-tube; style filiform, fleshy, incurved, 

 with a stca: obtuse terminal stigma; ovules 2-ranked, attached to the inner angle 

 of the c-^'ary. Legume stalked, oblong or broadly linear, straight on the upper, 

 curveo on the lower edge, acute at the ends, compressed, tipped with the thickened 

 remuants of the style, many-seeded, 2-valved, the valves coriaceo-membranaceous, 

 Fir4,ny-veiued, tardily dehiscent by the dorsal and often by the wing-margined ventral 

 ^juture, dark red-purple and lustrous at maturity. Seeds suspended transversely on 

 ^ slender f unicles, ovate or oblong, compressed, the small depressed hilum near the 

 apex; seed-coat crustaceous, bright reddish brown; embryo surrounded by a thin 

 layer of horny albumen, compressed ; cotyledons oval, flat, the radicle short, straight 

 or obliquely incurved, slightly exserted. 



