528 PROCEEDINGS OF THE AMERICAN ACADEMY. 



opposite branches : leaves linear-oblong, entire, acute at each end, green 

 on both sides, revolute at the margins, 3-nerved, thickish, scabrous, 1.4 

 to 1.7 cm. long, 2 to 4 mm. broad, puberulent under a lens: heads scat- 

 tered, borne in the forks of the branches and terminally on short branch- 

 lets : pedicels about 7 mm. long, appressed gray-pubescent : scales of the 

 involucre ovate, narrowed to an obtusish or sometimes exjjanded and 

 obtuse tip : rays about 6, light yellow, oblong, 8 mm. in length. — Du- 

 rango, Mexico, 13 August, 1897, Dr. J. N. Hose, no. 2252. 



b. Leaves ovate. 



22. P. Mendezii, DC. Shrub, scabrous : leaves ovate-lanceolate, 

 short-petioled, serrulate or nearly entire : heads numerous, on erect stiff- 

 ish fastigiate pedicels: invokicral scales in about 3 rows, the outer ovate, 

 the inner oblong: rays "3 to 4" to 8. — Prodr. v. 608; Hemsl. 1. c, 

 182. — South Mexico at Villalpanda, Mendez. Type in herb. DC. ; 

 fragment in herb. Gray. To this species may be referred E. W. Nel- 

 son's no, 3433 from Chiapas, and Pringle's no. 7610 from Hidalgo. 



Var. cylindrocephalum. Leaves lanceolate: involucre more cylin- 

 drical ; scales in 4 rows. — Mountain side near Cuernavaca, Morelos, 

 altitute 2,500 m., C. G. Pringle, 22 May, 1898, no. 7658. Type in 

 herb. Gray. 



++ +♦ Leaves and heads large, the latter rather crowded at the ends of the branches : 

 inner scales of the involucre 8 to 12 mm. long. 



== Pubescence on branches and petioles fine, appressed : petioles not over 1 cm. 



in length. 



23. P. Berlandieri, DC. Leaves ovate, serrate or subentire, acute, 

 rounded or scarcely cuneate at the base, 5 to 9 cm. long, obscurely pubes- 

 cent : brauchlets slender, nearly glabrous : rays 1 cm. long. — Prodr. v. 

 608; Herasl. 1. c. 181. — South Mexico, Guichilapa, Berlandier, no. 

 1040; also Valley of Mexico, Bourgeau, no. 964, and Mexico without 

 locality, Schmitz. 



24. P. Klattii. Tall shrub (4 m. high) with spreading branches ; 

 brauchlets thickish, silky-pubescent with appressed hairs : leaves ovate- 

 lanceolate, acuminate at each end, finely gray-pubescent on both surfaces, 

 crenate-serrate or subentire, large for the genus, 1.5 to 1.9 dm. long, 

 6 to 7 cm. broad: scales of the large involucre very broad and rounded 

 at the summit; rays 12, oblong-lanceolate, 1.8 cm. long. — P. grande, 

 Ivlatt in Engl. Jahrb. viii. 43, not Hemsl. — On the Rio Risasalda, Cauca, 

 U. S. Colombia, altitude 1,400 to 1,800 m., 24 November, 1883, F. C. 

 Lehmann, no. 3282. Type in herb. Gray. 



