ROBINSON. — MEXICAN PLANTS. 827 



altitude 2,350 m., 28 January, 1899, no. 8057, and earlier in woods afc 

 base of mountains in the Valley of Mexico, Federal District, G November, 



189 6, no. 7328. 



S. neurophylla, Robinson & Greenman, n. sp. Erect strict 

 slender somewhat rigid herb, 3 to G dm. high : stem terete, puberulent, 

 simple or sparingly branched : leaves strictly opposite, thick, rigid, ap- 

 pressed, linear-oblong, longitudinally ribbed with many close parallel 

 nerves, 2 to 5 cm. long, 3 to 5 mm. broad, sessile by a subclaspiug base, 

 coneolorous, green and nearly glabrous upon each surface ; the lowest 

 shorter, the upper also much reduced and distant : heads capitately 

 aggregated at the summit of the stem ; bracts of the involucre rather 

 rigid, glandular-puberulent, acute, 5 to 7 mm. long: corolla white, 

 nearly glabrous : achene dark nearly black, hispid both between and 

 upon the lighter colored angles ; pappus of 4 to G long almost plumose 

 awns and as many oblong intermediate scales. — Collected by E. W. 

 Nelson between Ayusinapa and Petatlan, Guerrero, Mexico, altitude 

 1,500 to 2,100 m., 14 December, 1894, no. 2133. Types in herb. Gray 

 and herb. U. S. Nat. Museum. 



S. Rosei. Herbaceous smoothish perennial herb with tough dark 

 fibrous roots: stems single, erect or slightly decumbent, 3 to 5 dm. high, 

 usually branched from the middle, puberulent (under a lens) with 

 crisped white hairs or quite glabrate ; branches opposite, ascending: 

 leaves opposite, sessile, oblong or lance-oblong, subcoriaceous, veiny, 

 crenate-serrate or nearly entire, usually obtuse, with 3 to 5 more or less 

 anastomosing nerves: heads in several small dense somewhat leafy- 

 involucrate capitate corymbs, these together forming a very loose leafy 

 corymb; involucral bracts green, linear, attenuate, very acute, 8 to 10 

 mm. long, almost glabrous, not much surpassed by the white or pale 

 purplish corollas : achenes black, glabrous ; pappus of 3 or more oblong 

 obtuse scales with or without 2 or 3 naked awns. — Collected by Dr. 

 J. N. Rose on the Sierra Madre, west of Balafios, Jalisco, 15 to 17 

 September, 1897, no. 2994; also in the state of Durango, 13 August, 



1897, no. 2258. This species is evidently related to S. Pringlei, but 

 differs in its short-pedicelled glomerate heads, larger leaves, etc. It is 

 also related to »S. venosa, Gray, and S. Plummerae, Gray, but differs 

 from both in inflorescence and character of its involucral bracts. 



S. Seleriana. Stems stoutish, lignescent, terete, white-lauate upon 

 the younger internodes, soon arachnoid, glabrate, and at length verrucose 

 with prominulous lenticels : leaves all opposite, decussate, petiolate, 

 oblong, crenate at the sides, subentire at the acutish apex ; entire at the 



