144 House: NortH AMERICAN CONVOLVULACEAE 
Type species: Calycobolus emarginatus Willd. 7. c. = Dufourea 
sericea H.B.K. = Prevostea sericea Choisy. 
Dufourea H.B.K. Nov. Gen. & Sp. 3: 113. 1818. Not Du- 
fourea Bory, 1810. 
Prevostea Choisy, Ann. Sci. Nat. 4: 497. 1825.—  Mém. Soc. 
Phys. Genev.6: 492. 1833.—In DC. Prodr.g: 437. 1845. 
Reinwardia Spreng. Syst. 1: 527. 1825. Not Reinwardtia 
‘Dum. 1822. 
Wilberforcia Hook. f.; Planchon, in Hook. Ic. p/. 796. 1848. 
At least eight species are known, two in Mexico and six in 
South America. Of the South American ones, the type of the 
genus, C. sericeus, may extend into Central America, and is in- 
cluded in the following enumeration : 
Key to the North American species 
Foliage densely pubescent. 
Inflorescence few-flowered on short peduncles. Mexican. 1. C, velutinus. 
Inflorescence many-flowered on long leafy peduncles. South 
i 2. C. sericeus. 
Foliage glabrous or nearly so. Mexican, 3. C. Pringlet. 
1. Calycobolus velutinus (Mart. & Gal.) 
Prevostea velutina Mart. & Gal. Bull. Acad. Brux. 122: 259. 
1845. 
Breweria mexicana Hemsley, Biol. Cent. Am. Bot. 2: 400. 1882. 
Porana velutina Hallier f. Bot. Jahrb. 16: 538. 1893. 
Softly pubescent, more or less erect and slender ; leaf-blades 
oblong-lanceolate, thick, 5-7 cm. long, acute, the base obtuse or 
rounded ; petioles 8-10 mm. long ; peduncles about 2 cm. long, 
few-flowered: the three outer sepals about 15 mm. long, ovate, . 
obtuse, glabrous at maturity, the two inner sepals subscarious and 
much smaller; corolla 2-2.5 cm. long, sparingly hirsute without ; 
anthers oblong ; ovary villous. 
TYPE LOCALITY: “In Mexico inter Tehuacan et Oaxacan prope 
la Venta de Argon.” 
DIsTRIBUTION: Southern Mexico, 
2. Calycobolus sericeus ( H.B.K.) 
Dufourea sericea H.B.K. Nov. Gen. & Sp. 3: 114. pl. rzg. 1818. 
Calycobolus emarginatus Willd.; R. & S. Syst. 5:4. 1816. 
