478 CAESALPINIACEAE 



1. Prosopis chilensis subsp. glandulosa (Torr.) Standley. Mesquite. 



Fig. 2546. 



Prosopis glandulosa Torr. Ann. Lye. N.Y. 2: 192. 1828. 



Prosopis julifiora var. glandulosa Cockerell, Bull. N. Mex. Agr. Sta. 15: 58. 1895. 



Prosopis chilensis subsp. glandulosa Standley, Contr. U.S. Nat. Herb. 23: 1658. 1926. 



Much branched shrub or small tree, the widely spreading branches armed with axillary 

 spines. Leaves glabrous or sparsely puberulent on the petioles and the margins of the leaflets ; 

 leaflets 8-12 pairs, linear, 12-15 mm. long; spikes 5-8 cm. long, usually densely flowered; pedicels 

 2 mm. long; pods straight or slightly falcate, usually only 1-3 developing, 10-15 cm. long, 10-12 

 mm. wide, longitudinally veiny, narrowed to a short stipe, straw-colored, sweetish when ripe. 



River bottoms and washes, Lower Sonoran Zone; interior valleys and desert regions of southern California 

 to Texas and southern Mexico. Type locality: New Mexico. April-June. 



Prosopis chilensis subsp. velutina (Wooton) Standley, Contr. U.S. Nat. Herb. 23: 1658. 1926. (Prosopis 



velutina Wooton, Bull. Torrey Club 25: 456. 1898.) Leaflets smaller than the preceding and distinctly pubes- 

 cent. Southern California to Arizona and Mexico. 



2. Prosopis pubescens Benth. Tornillo or Screw-bean. Fig. 2547. 



Prosopis pubescens Benth. Lond. Journ. Bot. 5: 82. 1846. 



Prosopis Emoryi Torr. in Emory, Notes Mil. Rec. 139. 1848. 



Strombocarpa pubescens A. Gray, PI. Wright. 1: 60. 1852. 



Prosopis odorata Torr. & Frem. in Frem. Second Rep. 313, in part. 1845. 



Shrub or small tree, attaining 10 m. in height, the trunk 1-3 dm. in diameter, the bark brown, 



separating into thin flakes, the branchlets armed with stout whitish spines. Leaves deciduous; 



leaflets 3-7 pairs on each pinna, oblong-linear, 1 cm. long or less, pubescent ; spikes 5-8 cm. long ; 



pods tightly coiled into a spiral 3-5 cm. long. 



River bottoms and washes, Lower Sonoran Zone; deserts of southern California to western Texas, Lower 

 California, Sonora, and Chihuahua. Type locality: not definitely known. May-Aug. 



Family 68. CAESALPINIACEAE. 



Senna Family. 



Herbs, shrubs, or trees with alternate, simple, or compound mostly stipulate 

 leaves. Flowers usually perfect, sometimes polygamous, monoecious or dioecious, 

 irregular or nearly regular. Calyx with 5 distinct sepals, or merely 5-toothed. Petals 

 usually 5, imbricated, the lower pair outermost, the upper odd ones enclosed by the 

 lateral pair. Stamens 10 or fewer, distinct or the filaments more or less united. 

 Ovary 1-celled, with one to many ovules. Fruit a legume, usually dehiscent into 2 

 valves; seeds with or without endosperm. 



About 90 genera and 1,000 species, mostly of tropical distribution. 



Leaves simple; flowers purple, very irregular and papilionaceous-like. 1. Cercis. 

 Leaves pinnate or bipinnate; flowers yellow, only slightly irregular. 



Leaves pinnate; sepals distinct. 2. Cassia. 

 Leaves bipinnate; sepals united into toothed or lobed calyx. 



Trees or arborescent shrubs, spinose. 3. Cercidium. 



Herbs or low shrubs, without spines. 4. Hoffmanseggia. 



1. CERCIS L. Sp. PL 374. 1753. 



Small trees or arborescent shrubs with simple leaves, and reddish-purple flowers borne 

 in lateral fascicles on the twigs of the preceding year. Calyx broadly campanulate, 

 slightly oblique, 5-toothed. Corolla irregular and simulating the papilionaceous ; petals 5, 

 the standard innermost and smallest, the keel petals larger than the wings. Stamens 10, 

 distinct, declined; anthers all alike. Ovary short-stipitate ; ovules many. Pod oblong or 

 linear-oblong, flat, the upper suture margined; valves thin, reticulate-veined; seeds com- 

 pressed, obovate, with endosperm. [The ancient name.] 



About 7 species, natives of North America, Europe, and Asia. Type species, Cercis Siliquastrum L. 



1. Cercis occidentalis Torr. Western Red-bud or Judas-tree. Fig. 2548. 



Cercis occidentalis Torr. ex A. Gray, Bost. Journ. Nat. Hist. 6: 177. 1850. 

 Siliquastrum occidentale Greene, Man. Bot. Bay Reg. 84. 1894. 

 Cercis latissima Greene, Rep. Spec. Nov. 11: 111. 1912. 

 Cercis nephrophylla Greene, Rep. Spec. Nov. 11: 111. 1912. 



Arborescent shrub or small tree, 2.5-5 m. high, twigs glabrous, bud scales more or less finely 

 ciliate on the margins.^ Leaves round or round-reniform, 4-6 cm. broad, more or less deeply cor- 

 date with a narrow sinus, rounded at apex, glabrous and glossy on both surfaces, rather pale 



