378 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Glabrate unarmed shrub ; pinnae 2 to 4 pairs, the leaflets narrowly elliptic, 

 puberulent ; spikes 2.5 to 5 cm. long ; fruit flat, 7.5 to 15 cm. long, 8 mm, wide. 



31. Acacia coulteri Benth. ; A. Gray, PI. Wright. 1: 66. 1852. 

 Sonora to Tamaulipas and Hidalgo ; type from ZimapS^n, Hidalgo. 



Slender shrub or tree, 3 to 10 meters high, unarmed or nearly so, the trunk 

 sometimes 60 cm. in diameter ; leaflets 4 to 6 mm. long ; flowers whitish, in long 

 slender spikes ; fruit about 15 cm. long and 2 cm. wide, flat. " Tepeguaje " 

 (Durango) ; "palo de arco," "huajillo" (Tamaulipas). 



Wood very hard ; used for tool handles, general construction, and fuel. 



32. Acacia acatlensis Benth. Lond. Journ. Bot. 1 : 513. 1842. 

 Acacia sericea Mart. & Gal. Bull. Acad. Brux. 10^: 309. 1843. 

 Acacia pueblensis T. S. Brandeg. Univ. Calif. Publ. Bot. 4: 85. 1910. 

 Jalisco to Oaxaca, Veracruz, and Yucatan ; type from Acatlan. 



Tree, 3 to 8 meters high, armed with short stout spines, or sometimes un- 

 armed; leaflets oblong-linear, 2 to 5 mm. long; flowers white, in long spikes. 

 " Guayolote " ( Michoacan ) . 



33. Acacia glandulifera S. Wats. Proc. Amer. Acad. 25:147. 1890. 

 Coahuila ; type from Carneros Pass. 



Shrub, about 60 cm. high ; spines stout, about 1 cm. long ; leaflets few, 2 to 3 

 mm. long ; flower heads 5 to 7 mm. in diameter ; fruit 6 to 8 cm. long, about 7 

 mm. wide, very rough. 



34. Acacia biaciculata S. Wats. Proc. Amer. Acad. 21:452. 1886. 

 Chihuahua ; type from sandy plains near the city of Chihuahua. 



Shrub, the prostrate branches a meter long or shorter ; spines very slender, 1 

 to 1.5 cm. long; leaflets few, 3 to 4 mm. long; flowers orange, in small long- 

 pedunculate heads; fruit 3 to 4 cm. long, 4 mm. wide, compressed, falcate, 

 pubescent. 



35. Acacia constricta Benth.; A. Gray, PI. Wright. 1:66. 1852. 



Sonora to Tamaulipas, Puebla, and Zaeatecas, on dry plains and hillsides, 

 often forming extensive thickets. Western Texas (type locality) to soutliern 

 Arizona. 



Shrub, 1 to 6 meters high, with reddish brown branches ; spines 1 to 2.5 cm. 

 long; leaflets mostly 2 to 3 mm. long; flowers yellow, sweet-scented; fruit 6 to 

 12 cm. long, 3 to 4 mm. wide, constricted between the seeds. " Huisache " 

 (Zaeatecas, Coahuila, etc.); " gigantillo," "vara prieta," " chaparro prieto " 

 (Durango, Patoni) ; " largoncillo " (Chihuahua). 



36. Acacia vernicosa Standi. Contr. U. S. Nat. Herb. 20: 187. 1919. 



Sonora and Chihuahua to Zaeatecas and Queretaro; type from Santa Rosalia, 

 Chihuahua. Western Texas to southern Arizona. 



Shrub, 1 to 2 meters high, similar to the preceding species. 



37. Acacia famesiana (L.) Willd. Sp. PI. 4:1083. 1806. 

 Mimosa famesiana L. Sp. PI. 521. 1753. 



Vachellia lamesiana Wight & Am. Prodr. Fl. Ind. Orient. 272. 1834. 



Nearly throughout Mexico. Widely distributed in tropical and subtropical 

 regions of both hemispheres ; probably adventive in the Old World ; type from 

 Santo Domingo. 



Shrub or tree, 1 to 9 meters high, the short trunk sometimes 45 cm. in diameter, 

 the branches spreading or drooping; bark thin, peeling ofE in long, reddish 

 brown scales ; spines 1 to 2.5 cm. long ; leaflets 2 to 6 mm. long ; flowers bright 

 yellow, very sweet-scented; fruit dark brown or purplish; wood hard, close- 

 grained, brownish red to yellow, its specific gravity about 0.83. " Binorama " or 

 "vinorama" (Sonora, Baja California, Sinaloa) ; "huisache" or "huizache" 



