154 PROCEEDINGS OF THE AMERICAN ACADEMY. 



the disk ; disk-corollas considerably longer than the involucre : awns 

 of the disk-achenes 2, longer than the body of the achene, much exceed- 

 ing the involucre ; ray-achenes slightly margined, with 2 tooth-like awns 

 and one slender and bristle-like. — ■ Contrib. U. S. Nat. Herb. i. 103 

 (1891). — Western Mexico. Specimens examined, — Sonora : Alamos, 

 Palmer, no. 645, coll. of 1890 (co-type, in herb. Gray). 



-t- -i- Heads numerous ; peduncles fasciculate, terminal and subterminal. 



++ Involucral bracts 2 mm. or more broad, imbricated in several series, commonly 

 appressed ; beads small ; involucre generally less than 5 mm. broad. 



= Achenes 4 to 5 mm. long, those of the ray-flowers 3-awned, the awns on the 

 outer angles short, tooth-like, on the inner long and bristle-formed ; achenes 

 of the disk-flowers with 2 awns as long as the body. 



1. Some of the outer bracts of the involucre reflexed : petioles generally over 



1 cm. long. 



19. Z. gracilis, n. sp. Shrub with long very slender branches : leaves 

 ovate to lanceolate, 5 to 10 cm. long, 2 to 4 cm. wide, acuminate to 

 rounded at the base, very acute or acuminate at the apex, serrate except 

 near the ends, strigose above, the hairs with swollen bases, the lower 

 surface sparsely short-strigose ; petioles 5 to 15 mm. loDg : peduncles 4 

 to 8 cm. long, slender, commonly in 3 or 4 of the upper axils, superposed ; 

 heads 1 to 1.5 cm. high ; involucre 4 to 7 mm. broad, cylindrical, 2-3- 

 seriate ; outer bracts considerably the shortest, generally reflexed, ciliate : 

 ligules orange-yellow: achenes as in the preceding species. — Western 

 Mexico. Specimens examined, — Colima : Colima, Palmer, no. 1G3, 

 coll. of 1897 (type, in herb. U. S. Nat. Mus.). 



2. Outer bracts of the involucre not recurved or reflexed : petioles less than 1 cm. 



long. 



20. Z. ceanothifolia, Sch. Bip. Shrub 2 to 3 m. high ; branches 

 striate, roughened by lenticels ; branchlets pubescent : leaves from 

 broadly ovate to narrowly oblong-lanceolate, usually ovate-lanceolate, 

 acute or acuminate at the apex, acute to rounded at the base, serrulate, 

 reticulate-veiny, sparsely scabrous-pubescent to densely strigose above, 

 strigose to coarsely and densely pubescent beneath ; petioles 5 to 10 mm. 

 long : peduncles 1 to 3 cm. long, in terminal or subterminal fascicles ; 

 heads 5 to (occasionally) 10 mm. high; involucre 3-5-seriate, 4 to 5 mm. 

 broad ; outer bracts ovate, very obtuse to abruptly acuminate, much 

 shorter than the inner: ligules 5 to 7, oblong, emarginate, orange-yellow ; 

 disk-flowers numerous: ray-achenes 4 mm. long, about 1 mm. wide, 

 linear-ovate, with narrow margins, their pappus of 2 short teeth and one 



