ROBINSON AND GREENMAN, —- GENUS TRIDAX. 9 
Galeotti, no. 2472. A species not seen by the writers. The description 
is translated and condensed from the original characterization. 
+ + Leaves very narrow, linear or lance-linear, or deeply cleft into narrow di- 
visions : heads rather small, 4 to 6 lines broad: rays small, bilabiate, the 
external lip trifid. 
/ 17. T. coronopifolia, Hemsl. Low, much branched and spreading, 
pubescent or hirsute; leaves lance-linear, denticulate, lacinately toothed 
or pinnatifid with narrow linear unequal acute segments: peduncles 
slender, toward the summit finely strigillose with appressed white hairs, 
and lacking the glandular-tipped hairs so common in the genus: rays 
yellow (or white) : pappus scales unequal, some of them subulate and 
ciliated, others plumose with scarcely dilated base. — Biol. Cent.-Am. 
Bot. ii. 207. Prilostephium coronopifolium, HBK. Nov. Gen. & Spec. 
iv. 255, t. 387. e have little hesitation in including in this species 
also Tridax trifida, Gray, Proc. Am. Acad. xv. 39 (Ptilostephium tri- 
Jidum, ABK. 1. ¢. 255, t. 388), notwithstanding the considerable differ- 
ence in the pappus represented by Kunth. After the examination of a 
number of Specimens we doubt the specific significance of the difference in 
length of the pappus, and as to the difference in the breadth of the scales 
that is often considerable upon the same achene.— Mexico without lo- 
ality, 7h. Coulter, nos. 348, 430, and Berlandier; State of Mexico, 
Bilimek, no, 491, also Bourgeau, nos. 164, 705; Tacubaya, Schaffner ; 
Mt. Orizaba, altitude 9,000 feet, Seaton, no. 273; Oaxaca, Soledad de 
Etla, altitude 5,300 feet, LZ. C. Smith, no. 361, and by same collector at 
elixtlahuaca, no. 866; also by H#. W. Nelson, in Valley of Oaxaca, 
altitude 5,100 to 9,800 feet, no. 1229. The formal variety ALBORADIATA 
- trifida, var. alboradiata, Gray, Proc. Am. Acad. xv. 39), with white 
Tays, but apparently without other significant or constant differences, has 
® somewhat more northerly distribution, having been collected at San 
Luis Potosi, Schaffner, no. 239, Parry § Palmer, no. 511; in Jalisco, 
Pringle, no. 2902; and in Guanajuato, Dugeés, no. 438. 
18. T, lanceolata, Klatt. “Lower leaves broadly lanceolate and 
"pper lance-linear, entire: chaff obovate.” — Leopoldina, xxiii. 6. — 
“Tehuacan, Liebmann, no. 205; Cuernavaca, Berlandier, no. 1063.” A 
Species not seen by the writers and (as to description) distinguished from 
the Preceding species chiefly by the characters quoted. of 
9. T. imbricata, Schz. Bip. “Leaves linear-lanceolate, entire, 
ot 1-3-toothed, pilose, ciliated on the margins: external scales of the 
nvolucre obtuse, Striate, dorsally puberulent.” — Schz. Bip. in Klatt, 
ra, 1885, 202. — « Real del Monte, Ehrenberg, no. 355.” We suspect 
to be merely a form of 7. coronopifolia. 
