30 PROCEEDINGS OF THE AMERICAN ACADEMY. 



glabrous above, pilose on the nerves beneath : heads pedicellate in 

 lanceolate-bracted corymbs : scales of the involucre biseriate, ovate, 

 striate : rays 4 or 5, oblong ; disk-flowers externally pubescent : chaff 

 ovate, scarious, obscurely dentate at the apex : scales of the pappus 

 linear-lanceolate, laciniate at the apex, shorter than the tetragonal hirsute 

 achene. — Leopoldina, xxiii. 6. Tetrachyron Orizabaeiisis, Schz. Bip.^rfe 

 Klatt, 1. c. — Peak of Orizaba, altitude 8,000 to 10,000 feet, Liebmann, 

 no. 390. Not seen by the writers. Description translated and condensed 

 fi'om the original characterization. 



Subgenus 5. Tephrocalea, Gray. Heads few or solitary, rather 

 large for the genus : scales of the pappus 4 to 5 : leaves ovate, entire, 

 j}.brupt at the base and slender-petioled, cauescent-tomentose or -tomentu- 

 lose beneath. — Proc. Am. Acad. xv. 38. 



26. C. discolor, Gray, 1. c. Leaves ovate-oblong, obtusish, mu- 

 cronulate, glabrous above, very finely tomentulose beneath : heads about 

 5 at the summits of the branches, 9 lines in diameter including the 

 spreading rays : pedicels long, an inch or more in length, very finely 

 puberulent or nearly smooth. — Mexico without locality, Th. Coulter, no. 

 351. A very distinct species apparently never rediscovered. 



27. C. tomentosa. Gray, 1. c. Leaves ovate, subcordate, rounded 

 at the apex, densely tomentose and canescent upon both surfaces when 

 young but glabrate above : heads solitary, terminal : peduncles very 

 tomentose, rather stout and somewhat thickened upward. — Between San 

 Luis Potosi and Tampico, Palmer, no. 1108. Not since collected. 



Species of uncertain affinities. 



28. C. sessiliflora, Less. Shrub: leaves very obtuse or subcor- 

 date at the base: heads discoid, about 10-flowered: involucre cylindrical: 

 chaff broad, obovate, muticous at the apex. — Linnaea, v. 158. — Mexico, 

 Hnmholdt. A species as yet wholly obscure ; the characters are drawn 

 from Lessing's scanty descri^Dtion. 



