220 BOTANICAL GAZETTE [MARCH 
nomenclature. In 1837 DeCandolle published C. mexicana, based 
upon Berlandier’s nos. 430 and 1750, collected between Bexar and the 
Trinity River, Texas. Later, C. mexicana was shown to be identical 
with C. americana Nutt. 
A careful study of a large suite of specimens in the Gray Herba- 
rium shows very clearly that we have at least two indigenous species 
of this genus in the southwest, one of which is new to science, and is 
readily separated from the older species on the involucral characters 
alone; its distribution, moreover, is more western and southern, and 
it grows at a higher altitude. C. americana has been so well described 
and illustrated that it is unnecessary to present here more than the 
literature and the citation of specimens. Of its congener, however, a 
description is given below. The two indigenous North American 
species as here recognized by the writer are as follows: 
*Involucral bracts stramineous or the inner ones slightly purplish, pectinate with 
3-8 pairs of lateral firm teeth. 
C. Americana Nutt. Jour. Acad. Phil. 2: 117. 1821; Bart. Fl. 
Am. Sept. 2: 4/50. 1822; Colla, Hort. Ripul. App.i. 119. p/.6. 1827; 
Reichb. Ic. Exot. 2: p/. 772. 1828; DC. Prodr. 6:575. 1837; Torr. & 
Gray, Fl. N. Am. 2; 453. 1843; Engelm. & Gray, Pl. Lindl. 14. 1845; 
Fl. Serres 4: f/. 327. 1848; Gray, Pl. Wright. 1: 125. 1852; Young, 
Fl. Texas 361. 1873; Meehan’s Nat. Fls. II. 2://. 77. 1880; Hemsl. 
Biol. Cent. Am. Bot. 2: 253. 1881 in part, 7. ¢., excl. pl. Rothrock; 
Gray, Syn. Fl. 17: 407. 1886; Coulter, Contrib. U. S. Nat. Herb. 
2: 244. 1891-94; Small, Fl. Southeastern U. S. 1308. 1903.— C. (Vut- 
tallii Spreng Syst. 4:(Suppl.) 298. 1827.—C. mexicana DC. Prodr. 
6:575. 1837.—Plectocephalus americanus Don in Sweet’s Brit. Fl. 
Gard. 2: f/. 57. 1831; Spach, Hist. Veg. 10: 63. 
UniTED States. Arkansas: specimen ex 4d. Durand. Louisiana: 
Dr. Leavenworth. Texas: Pope; Lindheimer, nos. 114, 343 dry prairies, 
near Dallas, Ha//, no. 373, Reverchon; Drummond, no. 169; between 
Bexar and the Trinity River, Berlandier, nos. 430, 1750; Kerr- 
ville, altitude 490 to 615™, Heller, no. 1774; Weatherford, 7racy, no. 
7896. New Mexico: Jornado del Muesto, Dr. Wislizenus; exp. from 
western Texas to El Paso, Wright, no. 405; White Mountains, alti- 
tude 1850", Wooton, no. 195. Mexico. Coahuila: Saltillo, Dr. 
Edward Palmer, nos. 766 (coll. of 1880), 294 (coll. of 1898) white- 
flowered form. Chihuahua: Bachimbo Cafon, Pringle; Rio Sta 
Maria, 7huréder, no. 748. 
