ROBINSON AND GREENMAN.— GENUS TRIDAX. 5 
ous showy heads 10 lines to an inch in diameter, with dark purple 
involucre and broad bright orange-yellow rays. — Galinsoga trilobata, 
Cav. Icon. iii. 42, t. 282; Bot. Mag. t. 1895; Sweet, Brit. Fl. Gard. 
t. 56. Sogalgina trilobata, Cass. Dict. Sci. Nat. xlix. 597. — Valley of 
Mexico, Bourgeau, no. 846; near Chapultepec, Schaffner ; and on calca- 
reous bluffs, Flor de Maria, Pringle, no, 3148; also in Michoacan in 
fields near Patzcuaro, Pringle, n . The form without any trace 
of pappus does not appear to differ in any other particular. A specimen 
cultivated in the Botanic Garden of Harvard University has leaves 
oblong, subentire. 
= = Pappus about equalling or somewhat exceeding the achenes. 
a Bs balbisioides, Gray. Annual, much branched, pubescent: 
branches divaricate or the lowest decumbent: leaves from lanceolate and 
irregularly toothed to deeply ternately cleft or pinnately parted: heads 
rather numerous, nearly or quite an inch in diameter, with convex or 
conical disk and spreading showy rays: ligules (exclusive of tube) 2} to 
4 lines long, as broad or broader. — Proc. Am. Acad. xv. 39. 7’. coro- 
nopifolia, Gray, 1. c., not Hemsl. Galinsogea balbisioides, HBK. Nov. 
Gen. & Spee. iv. 253, t. 386. Sogalgina balbisioides, Cass. 1. c. xlix. 
398. — Originally collected in Guanajuato between the Valley of San- 
ago and Lake Palangeo, at 5,500 feet altitude, by Humboldt 3 Bonpland. 
It is described and figured by Kunth, l. c.,.as having entire or repan 
ligules of suborbicular contour. No plants with this character have 
Since been observed, and we follow Dr. Gray in referring to the species 
the following, which differ only in their more or less distinctly 3-toothed 
"ays: Schaffner’s no. 238, and Parry & Palmer’s no. 509, both from San 
Luis Potosi. Nor does 7. leptophylla, Gray (1. c. xxi. 391), from Chihua- 
hua (Palmer’s no. 425, and Pringle’s no. 769), appear to differ by any 
constant or satisfactory character. A form from San Luis Potosi, repre- 
sented by Pi arry & Palmer’s no. 508, has the ligules sometimes 3-toothed 
and sometimes divided nearly to the base into 3 oblong lgbes. This 
plant was rather confidently referred by Dr. Gray (1. c. xv. 39) to f. 
“oronopifolia, but it differs from that species decidedly in its much imbri- 
cated inolucre, with very unequal and rounded scales, and in its attenuate 
chaff. Nor is the ligule strap-like. In stating it to be so Dr. Gray had 
cepa observed only one of the long oblong lobes of a very deeply 
Id ray, : 
8. T. petrophila. Distinctly perennial from a lignescent base: 
Stems several, very slender, erect or nearly so: branches ascending: leaves 
very narrow, linear, entire, toothed, or with 2 or 3 short linear lobes: _ 
