704 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
KEY TO THE SPECIES, 
Leaves simple. 
Outer bracts about equaling the inner; achenes not corky on 
the angles.......... 2... cee eee eee eee eee cece cee 1.°B. prionophylla. 
Outer bracts as long as the rays or longer; achenes corky on 
the angles. ... 2.2.22... 22 eee eee ee eee e nese eeseeeeees 2. B. glaucescens. 
Leaves pinnate or pinnatifid. 
Achenes flat, obovate or cuneate.............---0-002202.--- 3. B, frondosa, 
Achenes linear, tetragonal. 
Divisions of the leaves lanceolate, oblong, or ovate. 
Leaves once pinnate, the divisions sometimes pin- 
natifid into large divisions, thick and firm..... 4, B. anthriscoides . 
Leaves thrice parted or more into small divisions, 
thin... 2.0.0... eee cee eee e eee 5. B. bigelovit. 
Divisions of the leaves linear or linear-filiform, 
Divisions of the leaves linear-filiform............... 6. B. heterosperma., 
Divisions of the leaves linear. 
Heads of achenes narrow, 8 mm. wide or less; 
bracts nearly glabrous, the outer much 
shorter than the inner..............2.... 7. B, cognata. 
Heads of achenes broad, 10 mm. wide or more; 
bracts strongly villous, the outer about 
equaling the inner...................... 8. B. tenwisecta. 
1. Bidens prionophylla Greene, Pittonia 4: 256. 1901. 
Type Locauiry: ‘River Moira, Ontario.”’ 
Rance: British America to New Mexico and Illinois. 
New Mexico: Lower Plaza (Wooton). Wet ground. 
2. Bidens glaucescens (ireene, Pittonia 4: 258. 1901. 
Type Locauity: “Peculiar to the western mountain districts and the plains adja- 
cent, but beginning in Kansas, perhaps in Missouri.’’ 
Rance: British America to Kansas and New Mexico. 
New Mexico: Farmington; west of Clayton. Wet ground, in the Upper Sonoran 
Zone. 
3. Bidens frondosa L. Sp. Pl. 832. 1753. 
Tyre Locauity: “Habitat in America septentrionali,”’ 
Range: British America to Florida, Texas, and New Mexico. 
New Mexico: Farmington; Albuquerque. Wet ground, in the Upper Sonoran 
Zone, 
4. Bidens anthriscoides DC. Prodr. 5: 600. 1836. 
Type Locauity: ‘In Mexici Cordillera de Guachilaqua,”? 
Rance: Southern New Mexico, south into Mexico, 
New Mexico: Mesilla Valley (Wooton). Lower Sonoran Zone. 
As nearly as we can judge from the description and from the Mexican specimens 
examined, this collection belongs here. It exactly matches specimens collected by 
‘almer near Durango. The plant is closely related to Bidens pilosa L., a species of 
Mexico and the West Indies found in California, but has different leaves, pubescence, 
and achenes. 
5. Bidens bigelovii A. Gray in Torr. U. S. & Mex. Bound. Bot. 91. 1859. 
Type Locauiry: Banks of the Rio Limpio, Texas. 
Rance: Western Texas to southern Arizona and southward. 
New Mexico: Mangas Springs; Kingston; West Fork of the Gila; Organ Mountains, 
Canyons, in the Upper Sonoran Zone. 
