LEGUMINOS^ 627 



brown, very glandular, fully grown at midsummer, ripening before the end of August. 

 2'-2i' long.' 



A tree, sometimes 25-30 high, with a short trunk occasionally 18' in diameter and 

 usually divided 4-6 above the ground into a number of stout upright branches, and 

 slender branchlets thickly coated at first with hoary-canescent pubescence disappearing 

 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, |'-j' long, and persistent at least during two years. Bark of the 



Fig. 572 



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 sometimes 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. ERYTHRINA L. 



Trees or shrubs with erect terete stems and branches, often armed with recurved prickles, 

 or rarely herbaceous. Leaves alternate, pinnately ST-foliolate; stipules small, the stipels 

 gland-like. Flowers papilionaceous, showy, in pairs or fascicled on the rachis of axillary 

 leafless racemes, or in terminal racemes furnished at base with leaf-like bracts; calyx ob- 

 lique, truncate or 5-toothed; corolla usually scarlet; petals free; standard broad or elon- 

 gated, erect or spreading, nearly sessile or raised on a long stalk; wing-petals small or 

 wanting, longer or shorter than the keel-petals; stamens 10, united into a tube split on 

 the upper side, the tenth and upper stamen separate or all 10 united; anthers uniform; 

 ovary stipitate, 1-celled; styles subulate, incurved, naked; stigmas small, terminal; ovules 

 numerous, amphitropous, the micropyle superior. Fruit a stipitate linear-falcate pod nar- 

 rowed at ends, compressed or subterete, constricted or undulate between the seeds, 

 2-valved; seeds reniform, attached by an oblong basal hilum, exalbuminous. 



From twenty-five to thirty species are recognized, all inhabitants of tropical and semi- 

 tropical regions. In the gardens of warm countries several of the species are cultivated 

 for the beauty of their large and brilliant flowers. 



The name is from tpv0p6s, in allusion to the color of the flowers. 



