1202 CONTRIBUTIONS FROM THE NATIONAL HEEBAKIUM. 



Glabrous woody vine; leaves broadly cordate, 6 to 8 cm. long, long-acumi- 

 nate, entire or coarsely dentate ; corolla 10 to 14 cm. long, the limb 8 to 10 

 cm. broad ; seeds finely pubescent. 



6. EXOGONIUM Choisy, M6m. Soc. Phys. Hist. Nat. Geneve 6: 443. 1833. 



Reference: House, The genus Exogonium, Bull. Torrey Club 35: 97-107. pi. 



1, 2. 1908. 



Woody vines; leaves usually entire; flowers solitary or in axillary cymes 

 or racemes, the bracts often large and colored ; sepals equal or unequal ; co- 

 rolla subtubular, red, white, or j'ellow, the tube long, the limb very narrow; 

 stamens and style protruding ; ovary 2-celled, 4-ovulate ; stigma capitate, bi- 

 lobate; seeds usually hairy. 



Corolla yellow. Bracts inconspicuous 1. E. luteum. 



Corolla red or pink. 



Bracts cordate, purple or pink 2. E. bracteatum. 



Bracts never cordate, green or minute and caducous. 



Flowers sessile in the upper axils 3. E. velutifolium. 



Flowers pedicellate, in cymes. 



Corolla glabrous outside 4. E, argentifolium. 



Corolla pubescent outside 5. E. conzattii. 



N 1. Exogonium luteum House, Bull. Torrey Club 35: 103. pi- 2, f. c. 1908. 

 Type from Cuesta de Chiqulhuetlan, Oaxaca, altitude 990 meters. 

 Stems minutely pubescent ; leaves deltoid-ovate, 5 to 8 cm. long, acuminate, 

 pubescent ; cymes long-pedunculate, many-flowered ; corolla 3 to 5 cm. long. 



2. Exogonium bracteatum (Cav.) Choisy; Don, Hist. Dichl. PI. 4: 264. 1838. 

 Ipomoea bracteata Cav. Icon. PI. 5: 51. pi. 4^7. 1799. 



Ipomoea spicata H. B. K. Nov Gen. & Sp. 3: 112. 1819. 



Ipomoea cincta Roem. & Schult. Syst. Veg. 4: 254. 1819. 



Convolvulus obvallatus Spreng. Syst. Veg. 1: 595. 1825. 



Exogonium olivae Barcena, Viaje Cav. Cacahuam. 29. 1874. 



Convolvulus bractiflorus Sess6 & Moc. PI. Nov. Hisp. 23. 1887. 



Baja California to Chihuahua, Morelos, and Oaxaca ; type from Mazatlftn 

 (Guerrero ?). 



Woody vine, glabrous throughout ; leaves ovate-cordate, 6 to 9 cm. long, long- 

 acuminate ; flowers racemose, the bracts reniform, 2 to 3.5 cm. long, imbricate, 

 obtuse or acute, prominently veined ; corolla 3 to 3.5 cm. long. " Jlcama " 

 (Sonora) ; " bejuco bianco" (Sinaloa) ; "azalea de la barranca" (Jalisco); 

 " carnestolenda " (Guerrero, Langlass6) ; " gallinitas del cerro," " empada- 

 nilla " (Oaxaca, Reko) ; " flor de candelaria " (Guerrero). 



When in flower the plant is very showy, rivaling Bougoinvillea, which it 

 strongly suggests. The leaves are usually but not always absent at the time 

 of flowering. The roots are large, watery, and sweet, and they are often 

 eaten along the Pacific coast, either raw or cooked. The plant is illustrated 

 by Hernandez.* 



Exogonium bracteatum pubescens (Robins. & Greenm.) House,* described 

 from Guadalajara, is a pubescent form. 



' Thesaurus 388. 1651. 



*Bull. Torrey Club 35: 101. 1908. Ipomoea bracteata pubescens Robins. & 

 Greenm. Amer. Journ. Sci. 50: 160. 1895. 



