712 CONTEIBUTIONS FROM THE NATIONAL HERBARIUM. 



dried and powdered stems are employed in making dentifrices, liaving been 

 exported to Europe for ttiis purpose. The stems are bitter, and they were 

 formerly used in Jamaica as a substitute for hops in brewing beer. The 

 leaves have been employed for dropsy and affections of the stomach. The 

 flowers are much frequented by bees. 



3. Gouania mexicana Rose, Contr. U. S. Nat. Herb. 3: 314. 1895. 

 Sonora and Sinaloa ; type from CuliacS^n, Sinaloa. 



Slender scandent shrub with tomentulose branchlets ; leaves slender-petiolate, 

 ovate-oblong to oblong-elliptic or broadly ovate, 6 to 9 cm. long, acute, rounded 

 or subcordate at base, densely pubescent on both surfaces, irregularly serrate ; 

 fruit 4 to 6 mm. broad, densely tomentose. 



4. Gouania polygama ( Jacq.) Urban, Symb. Antill. 4: 378. 1910. 

 Rhamnus polygama Jacq. Enum. PI. Carib. 17. 1760. 

 Gouania tomentosa Jacq. Stirp. Amer. 263. 1763. 



San Luis Potosf, Veracruz, Oaxaca, and Chiapas. West Indies, Central 

 America, and northern South America. 



Stems densely tomentulose ; leaves elliptic, broadly ovate, or ovate-elliptic, 

 5.5 to 11 cm. long, obtuse and abruptly short-acuminate, usually subcordate 

 at base, coarsely crenate or serrate, thinly or densely tomentose beneath ; fruit 

 10 to 12 mm. broad, tomentose or in age glabrate. " Jaboncillo " (Panama). 



The bark is said to contain saponin. 



5. Gouania conzattii Greenm. Field Mus. Bot. 2: 257. 1907. 



Guerrero to Oaxaca and Puebla ; type from Cerro de San Felipe, Oaxaca, 

 altitude 1,700 meters. 



Stems tomentulose or glabrate; leaves short-petiolate, ovate-elliptic, 5 to 9 

 cm. long, acute or short-acuminate, subcordate at base, thinly tomentulose be- 

 neath, irregularly crenate ; fruit 8 to 13 mm. wide, glabrate. " Espumilla " 

 (Guatemala) ; " enredadera " (Oaxaca, Conzatti). 



Perhaps only a form of O. polygama. 



2. ZIZYPHUS Adans. Fam. PI. 2: 304. 1763. 



Trees or shrubs ; stipules often developing into spines ; leaves alternate or 

 opposite, 3-nerved, deciduous ; flowers in axillary cymes ; calyx 5-lobate ; petals 

 5, cucuUate ; stamens 5 ; fruit drupaceous, the stone 1 to 3-celled. 



Zizyphus saliva Gaertn. is cultivated in southern Europe for its edible fruit. 

 Z. juixiba Lam., the jujube, also is cultivated for its fruit, from which is 

 obtained the jujube paste used in confectionery. 



Leaves cuspidate-acuminate ^ 4. Z. acuminata. 



Leaves rounded or very obtuse at apex. 



Inflorescence pubescent ; leaf blades cordate or rounded at base ; branches 



green 1. Z. sonorensis. 



Inflorescence glabrous ; leaf blades often cuneate at base ; branches brown. 



Leaves 3 to 7 cm. long 2. Z. mexicana. 



Leaves 1 to 3 cm. long 3. Z. pedunculata. 



1. Zizyphus sonorensis S. Wats. Proc. Amer. Acad. 24: 44. 1889. 



Zizyphus seleri Loesener, Verb. Bot. Ver. Brand. 51: 29. 1909. 



Zisyphus endlichii Loesener, Repert. Sp. Nov. Fedde 8: 296. 1910. 



Baja California and Sonora to Jalisco and Oaxaca ; type from Guaymas, 

 Sonora. 



Shrub or small tree, 2 to 12 meters high, the younger branches green and 

 often geniculate, armed with long stout spines ; trunk bark grayish ; leaves 



