264 PROCEEDINGS OF THE AMERICAN ACADEMY. 



natisect, 2 to 6 cm. long, 1 to 4 cm. broad, glabrous ; divisions linear, 

 acute : peduncles long, slender, 1.5 dm. or less in length, naked, sub- 

 anpressed-canescent-pubescent : heads few, including the fully expanded 

 rays 2.5 to 3 cm. in diameter : involucre campanulate, 5 to 6 mm. high ; 

 outer bracts of the involucre about 15, linear, acute, equalling or slightly 

 exceeding the inner ones, canous-pubescent, the inner bracts oblong- 

 lanceolate, obtuse, pubescent along the median line, scarious-margined : 

 ray-flowers 8 to 10, neutral; rays whitish or roseate: disk-flowers 

 yellow, numerous, 45 to 50 ; mature achenes linear, about 1 cm. long, 

 hirsute-hispid above, bearing 2 or 3 rather short retrorsely barbed awns 

 2 mm. or less in length, — Mexico. State of Michoacan : fields near 

 Uruapan, altitude 1525 m., 8 October, 1904, 0. G. Pringle, no. 8814 

 (hb. Gr.). 



Bidens rosea, Schz. Bip. in Seem. Bot. Herald, 308 (1852-57). 

 Cosmos pilosus, HBK. Nov. Gen. & Sp. iv. 241 (1824); Hemsl. Biol. 

 Cent.-Am. Bot. ii. 200 (1884). Although the Humboldt and Bon- 

 pland specimen on which this species was based has not been examined 

 by the writer, yet there are in the Gray Herbarium several specimens 

 which correspond fairly well with the original description. The mature 

 achenes in the material at hand are elongated, as in many species of 

 Bidens, but not attenuated above into a beak as in Cosmos, hence the 

 disposition of the plant as made by Schultz Bipoutinus is here main- 

 tained. The following collections are taken to represent the above 

 species : Mexico. State of San Luis Potosi : Alvarez, 28 September 

 to 3 October, 1902, Palmer, no. 192 (hb Gr.). State of Michoacan : 

 Los Reyes, 8 to 12 February, 1903, E. W. Nelson, no. 6868 (hb. Gr., 

 and hb. TJ. S. Nat. Mus.). Guatemala, Department of Santa Rosa : 

 Cuijiniquilapa, altitude 800 m., Heyde fy Lux, no. 6172 (hb. Gr.). 



Var. oalcicola, n. var. Leaves more divided ; divisions lanceolate : 

 involucre rather densely canous-pubescent. — Mexico. State of More- 

 los : on limestone hills, Yautepec, near Cuernavaca, altitude 1220 m., 

 21 October, 1902, C. G. Pr ingle, no. 11,340 (hb. Gr.). 



Bidens sarrnentosa, n. sp. A low almost prostrate herbaceous 

 perennial: stems freely branched, 1.5 dm. or less in length, glabrous 

 or bearing a few scattered hairs: leaves petiolate, bipinnate, 1 to 1.5 cm. 

 long, two-thirds as broad, glabrous on both surfaces ; segments obtuse 

 or obtusish : heads small, 5 to 7 mm. high, about 1 cm. in diameter in- 

 cluding the rays, borne on glabrous or essentially glabrous peduncles 

 4.5 cm. or less in length : involucre double, the outer bracts usually 5, 

 linear or liuear-spatulate, obtusish, glabrous, sometimes ciliate-margined, 



