152 PROCEEDINGS OF THE AMERICAN ACADEMY. 



volucre: achenes 6 to 7 mm. long, narrowly margined on the inner edge ; 

 squamellae minute or none. — Mexico. Specimens examined, — Guer- 

 rero: mountains near Iguala, alt. 1230 m., Pringle, no. 8411 (type, in 

 herb. Gray)." 



2. Scales of the involucre not recurved at the apex. 



14. Z. Ghiesbreghtii, Gray. Shrubby or arborescent: leaves 

 ovate-lanceolate, acuminate, reticulate, submembrauaceous, hirtellous- 

 scabrous, subcordate : peduncles terminal, solitary or in cymes of 3, 

 frequently thickened upward, several times longer than the upper leaves ; 

 heads about 15 mm. high ; involucre hemispherical, 1 to 2 cm. in diam- 

 eter, 3-seriate ; outer bracts orbicular-ovate, appressed, considerably 

 shorter than the others ; the inner long, narrower, membranaceous at the 

 tip: ligules orange-yellow, only slightly exceeding the disk; disk-flowers 

 numerous, generally exceeding the involucre: achenes somewhat mar- 

 gined, about 5 mm. long, 1 to 2 mm. wide ; awns, in the disk-achenes, 

 more than half as long as the body, in the ray-achenes shorter ; squamellae 

 minute. — PI. Wright, i. 113 (1852), as Ghiesbrechtii ; Hemsl. Biol. 

 Cent. -Am. Bot. ii. 172. — Mexico. Specimens examined, — Without 

 precise locality, Ghiesbreght, no. 385 (type, in herb. Gray). Colima: 

 Palmer, no. 1241, coll. of 1891. Guerrero: Acapulco, Palmer, no. 

 491, coll. of 1895; between Juchitango and Omelepec, Nelson, no. 2312. 

 Tepic : Palmer, Jan. 5 to Feb. 6, 1892. Some of these specimens have 

 been distributed as Z. Greggii, a species which should be readily distin- 

 guished by its prominent squamellae, very narrowly fusiform achenes, 

 and sessile leaves. 



15. Z. macrocephala, Hemsl. Suffruticose or fruticose, densely 

 pubescent above; leaves firm, subsessile, lanceolate to elliptical, attenu- 

 ate, serrate, short-pilose and more or less scabrous with tuberculate hairs 

 above, strongly reticulate-veiny and densely hirsute beneath ; peduncles 

 longer than the upper leaves, terminal, usually in cymes of 3 ; heads 1 

 to 2 cm. high; involucre 10 to 15 mm. broad; bracts somewhat decus- 

 sately arranged, ovate, from acute to rounded at the apex, outer pair 

 quite small : achenes rather long and slender (as in Z. Greggii), those 

 of the disk with slender awns less than half as long as the body, those of 

 the ray with tooth-like awns ; squamellae none. — Biol. Cent.- Am. Bot. 

 ii. 173 (1881). Lipochaeta macrocephala, Hook. & Arn. Bot. Beech. 

 Voy. 43G. — Southern Mexico. Specimens examined, — Guerrero: 

 Acapulco, Hinds, no. 1841 (a portion of the type material sent from 

 herb. Kew). 



