16 PROCEEDINGS OF THE AMERICAN ACADEMY. 



§ 2. Erect or procumbent herbs, sometimes a little woody at the base ; 

 stems and branches loosely spreading ; leaves linear, lance-linear, or ellip- 

 tic-oblong : rays rather short, suborbicular or quadrate to oblong, 2 to 6 

 lines in length, white or sulphur yellow. 



* Achenes with interrupted callous margins and somewhat tufted ciliation : 



slender erect annual with small heads and very pale or bright white rays. 



6. Z. -icolor, Hemsl. Becoming a foot or so in height: leaves 

 linear to lance-oblong, an inch to inch and half long, 1 to 4 lines broad, 

 obtuse. —Biol. Cent.-Am. Bot. ii. 153, as to syn., but not as to specimens 

 cited, except that of Mendez. Z. maritima, Gray, Proc. Am. Acad. xxii. 

 423, in part. Mendezia bicolor, DC. Prodr. v. 533 ; Deless. Icon. iv. t. 29. 



— West of Guanajuato, Mendez; San Luis Potosi, Scliaffner^ no. 337; 

 Jalisco, at Tequila, Palmer, no. 355, and on slopes of canons near Guada- 

 lajara, P/7«^^e, no. 2313. The last two distHbuted as Z. maritima, from 

 which this erect white-rayed plant of the inland is amply distinct. 



* * Achenes evenly margined and regularly ciliated ; rays yellow or orange. 



7. Z. Greggii. Slender pubescent herb, becoming scabrous, erect 

 or decumbent merely at the base : leaves linear or nearly so, 1-3-nerved, 

 sessile : heads slender-peduncled, terminating the spreading nearly naked 

 branches, these bearing mostly only a single pair of linear leaves : rays 

 varying from very short-oblong to half inch in length : disk-flowers 

 orange ; ray-flowers pale yellow ; ray-achenes about a line in length : 

 disk-achenes bearing a single slender awn. — Z. bicolor, Hemsl. 1. c. as 

 to plants of Coulter and of Seemann, but not as to syn. Z. maritima, 

 Gray, Proc. Am. Acad. xxii. 423, as to narrow-leaved form, not HBK. 



— Mexico, without locality, Gregg, 1848-1849, no. 1082; also Baites ; 

 W. Mexico, Seemann ; none of these specimens show the base perfectly, 

 but a plant apparently identical, collected by F. H. Lamb on plains at 

 Zopelote, Tepic, 9 February, 1895, no. 555, has a thickish perennial root. 



8. Z. littoralis. Procumbent spreading herb, probably of biennial 

 or perennial duration : stems leafy, branched, striate, puberulent : leaves 

 elliptic-oblong or elliptic-lanceolate, obtuse or obtusish at both ends, 3 (or 

 obscurely 5)-uerved and reticulated, green on both sides, 4 to 10 lines 

 long, a third to half as broad : heads scarcely peduncled, borne at the 

 ends of leafy branches: rays orbicular or nearly so, pale yellow, striate 

 and greenish toward the ends beneath : disk-flowers bright orange- 

 colored ; chaff oblong, very obtuse or truncate : achenes with a very 

 narrow cartilaginous margin, ciliated : pappus of a single awn with or 

 without a shorter second one : achenes of the ray-flowers about li lines 

 long, tuberculate. — Collected at Mazatlan by Th. Coulter, and redis- 



