148 PEOCEEDINGS OF THE AMERICAN ACADEMY. 



(1842). — Southern Mexico. Specimens examined, — Morelos : near 

 Cueruavaca, 1520 tn. alt., Pringle, no. G225 ; Ghiesbregkt, no. 379 (type, 

 in herb. Gray). 



*+ ++ Awns of the disk-achenes usually about half as long as the body. 



G. Z. Greggii, Gray. Shrub or lignescent herb, 2 to 3 m. high : 

 leaves large on the lower part of the stem, 1.5 dm. long, 8 cm. wide, 

 smaller above, sessile or nearly so, ovate to lanceolate, serrate, obtuse to 

 acuminate, cordate or subcordate, reticulate-veiny, scabrous : peduncles 

 2 to 25 cm. long, stout, naked or bearing 1 or 2 scale-like bractlets ; heads 

 about 15 mm. high; involucre 1.5 to 2.5 cm. broad, its bracts 3-seriate, 

 ovate or lanceolate, the outer attenuate, appressed, several-nerved, the 

 inner rounded and chartaceous at the summit : ligules rather small, com- 

 monly not exceeding the disk ; disk-corollas with long slender tubes, gener- 

 ally surpassing the involucre : achenes 5 to 6 mm. long, narrowly fusiform, 

 the angles only slightly margined ; squamellae about 1 mm. in length. 



— PI. Wright, i. 113 (1852); Hemsl. Biol. Cent.- Am. Bot. ii. 172. — 

 Southern Mexico. Specimens examined, — Jalisco : near Guadalajara, 

 Pringle, no. 1769; Tequila, Palmer, no. 356, coll. of 1886; between the 

 city of Mexico and Mazatlan, Gregg, no. 1003 (type, in herb. Gray). 



* * Squamellae minute (less than 0.5 mm. long or entirely wanting). 



«- Heads few, in terminal 3-headed cymes or solitary (in Z. frutieosa, the pe- 

 duncles commonly in several of the upper axils). 



++ Herbs, 3 to 9 dm. high, from tuberiform roots or thickened lignescent base. 



= Peduncles very long, usually not less than 1 dm. in length. 



7. Z. 1'Odocephala, Gray. Herbaceous, to 9 dm. high, somewhat 

 branched from a lignescent base; roots much thickened, fusiform; stems 

 spreading-hirsute, bearing about 5 pairs of leaves and 1 to 3 long-pedun- 

 cled heads : leaves subsessile, ovate-oblong to oblong-lanceolate, acute at 

 the apex, subcordate, rounded or abruptly narrowed to a subcuneate base, 

 serrate, (! to 8 cm. long, 15 to 32 mm. wide, coarsely pubescent on both 

 sides : heads ah >ut 1 cm. high ; involucre cylindrical or campanulate, about 

 1 cm. broad, 2-seriate; outer bracts oblong-ovate, subacute, hirsute: ray- 

 flowers about 12; ligules 13 mm. long; disk-corollas scarcely exceeding 

 the involucre: achenes 3 mm. long, widest at or near the summit; awns 

 shorter than the body, widened at the base, those of the ray-achenes 

 usually reduced to strong teeth ; minute squamellae sometimes present. 



— Syn. Fl. i. pt. 2. 286 (1884); Rose, Contrib. U. S. Nat. Herb. i. 

 103; Britton & Kearney, Trans. N. Y. Acad. Sci. xiv. 44. Verbesina 



