LEGUMIXOS^ 577 



and slender branchlets thickly coated at first with hoary-canescent pubescence dis- 

 appearing early in their second year, and then pale green and more or less spotted 

 and streaked with red, becoming pale brown in their third season, their spines 

 straight or slightly curved, very sharp and rigid, ^'-\' long, and persistent at least 

 during two years. Bark of the trunk thin, exfoliating in long longitudinal dark red- 

 brown scales. Wood very heavy, hard and strong, although brittle, rich dark 

 brown striped with red, with thin clear yellow sap wood; valued as fuel and some- 

 times manufactured into canes and other small objects. 



Distribution. Sides of low depressions and arroyos in the desert; valley of the 

 Colorado River south of the Mohave Mountains, California, to southwestern Arizona, 

 and to Sonora and Lower California; most abundant and of its largest size in Sonora. 



17. ICTHYOMETHIA, P. Br. 



A tree, with thin scaly bark, stout terete branchlets without terminal buds, coated 

 at first with thick rufous pubescence disappearing during the first summer, becom- 

 ing glabrous or glabrate, bright reddish brown, conspicuously marked by oblong longi- 

 tudinal lenticels and large elevated horizontal slightly obcordate leaf-scars marked 

 by the ends of numerous small scattered fibro-vascular bundles, and obtuse axillary 

 buds with tliin scales clothed with silky rufous hairs. Leaves unequally pinnate, 

 long-petiolate, 5-11-foliolate, deciduous ; leaflets opposite, oval, obovate or broadly 

 oblong, obtuse or shortly acuminate at the apex, rounded or wedge-shaped at the 

 base, with thick pubescent petiolules, at first coated like the petioles with rufous 

 hairs, at maturity coriaceous, glabrous and dark green above, pale and more or less 

 clothed below with rufous or canescent pubescence along the elevated conspicuous 

 midribs and numerous thin primary veins arching and united at the entire undulate 

 thickened margins, or sometimes covered with soft silky pubescence below. Flowers 

 papilionaceous, on slender pedicels enlarged at the ends, bibracteolate, in canescent 

 ovate densely flowered or elongated thyrsoidal panicles with short 3-12-flowered 

 branches, from axils of the fallen leaves of the previous year; bracts and bractlets 

 minute, scarious, coriaceous; calyx campanulate, canescent, 5-lobed, persistent, the 

 lobes imbricated in the bud, short and broad, the two upper subconnate, the lower 

 broadly triangular; petals inserted on an annular glandular disk adnate to the inte- 

 rior of the calyx-tube, unguiculate, white tinged with red; standard nearly orbicular, 

 emarginate, hoary-canescent on the outer, marked with a green blotch on the inner 

 surface, its claw as long as the calyx; wings oblong- falcate, auriculate at the base of 

 the blade on the upper side; keel-petals broadly falcate, the claws connate; stamens 

 10, the filament of the upper one free at the base only, united above with the others 

 into a long tube; anthers oblong, uniform, versatile; ovary sessile, sericeous, con- 

 tracted into a filiform incurved style, with a capitate stigma; ovules numerous, sus- 

 pended from the inner angle of the ovary, 2-ranked. Legume linear-compressed, 

 raised on a stalk longer than the calvx, sligfhtlv contracted between the numerous 

 seeds, tomentose-canescent or glabrate, thin-walled, indehiscent, longitudinally 

 4-winged, the wings developed from the dorsal and ventral sutures, and broad, contin- 

 uous or interrupted by the abortion of some of the ovules, membranaceous, softly 

 pubescent, their margins undulate or irregularly cut. Seeds oval, compressed, with- 

 out albumen, laterally attached by short thick funicles; seed-coat thin, crustaceous, 

 red-brown, not lustrous; embryo filling the cavity of the seed; cotyledons plano- 

 convex, oval, fleshy; radicle short, iuflexed. 



