OF ARTS AND SCIENCES. 177 



fibres : the base of the plant covered with brown wool, as in some 

 species of Cacalia : leaves including petioles a foot in length, pin- 

 nate, glabrous ; leaflets 4-6 pairs and an odd one, elliptic-lanceo- 

 late, acute at each end; the terminal one much larger, 8-10 lines 

 long, obscurely crenate, with minute glands in the sinuses of the 

 crenation; scapes a foot high, simple or branched, bearing one or 

 more linear bracts : involucre double, the outer bracts narrowly ob- 

 long, exceeding the broader inner ones, all obtuse : heads solitary, 

 exclusive of the rays \ inch in diameter: rays white, 4-5 lines 

 long, fertile : disk flowers yellow, their corollas destitute of an 

 annulus at the junction of the tube and throat: achenes slightly 

 ciliate on or near the summit, but without a distinct pappus. — 

 Wet meadows, Del Rio, State of Mexico, August, 1890 (n. 3668). 

 This plant approaches most nearly the genus Leptosyne, differing 

 from it, as heretofore limited, chiefly in its white rays and in the 

 absence of an annulus on the disk corollas. The neighboring 

 genera, Dahlia and Bidens, show, however, what variation is to be 

 expected in the color of the rays, and in L. Mexicana, Gray, which 

 Dr. Gray pronounces a good Leptosyne, there is scarcely a trace of 

 an annulus. Mr. Pringle's plant is certainly very distinct in its 

 habit from any known species of the genus. 



GEISSOLEPIS, n. gen. of the Compositse (Galinsogese). 

 Heads heterogamous, radiate. Flowers all fertile, rays white, disk 

 yellow. Involucre turbinate-campanulate ; scales ovate, obtuse, 

 closely imbricated in 4-5 rows, the outer regularly shorter. Re- 

 ceptacle chaffy in all parts, but not alveolate; chaff obovate, ob- 

 tuse, ciliate. Disk flowers regularly 5-toothed, throat not enlarged. 

 Anthers entire below. Style divided nearly to the middle; the 

 branches flattened, bearing short conical appendages. Achenes 4- 

 angled, pubescent, crowned with 7-8 very acute awl-shaped, mi- 

 nutely and retrorsely ciliated scales. — A prostrate, somewhat 

 succulent herb, with alternate entire linear leaves: heads small, 

 solitary on lateral peduncles arising opposite the leaves. This 

 genus is perhaps best placed just before Blepharipappus. The 

 generic name, derived from yda-aov and \enls, has reference to the 

 well imbricated scales of the involucre, one of the distinctive char- 

 acters of the genus. 



G. su^edjefolia. Stems prostrate, giving off numerous sub- 

 simple branches : branches 4-6 lines in length, finely pubescent, 

 especially at the nodes: leaves glabrous, fleshy, 6-8 lines long, 

 half a line in breadth, sessile: heads including rays 8 lines in 



VOL. XXVII. (n. s. xix ) 12 



