WiECiAND: Some Species of Bidexs 405 



in its characters, and although some cases of retrorsc awns have 

 been reported "^ none have been observed by the writer. Its 

 only close relative is B, melanocarpa from which it is often very 

 difficult to distinguish some of the smaller forms. The smaller, 

 more acuminate leaves, and smaller achcnes with upwardly barbed 

 awns arc the only reliable distinguishing characters. Some of the 

 western specimens are often quite robust The flowering period is 

 September and October. 



Stem Sc^/o 



3, Bidens melanocarpa sp. nov. 



rorr. FL N. Y.: Darl FL Cest Not L. 



branches mostly spreading : leaves pinnatcly 3-5-foliolate, glabrous 

 or nearly so except the scabrous margins, petioles very slender, 

 scarcely margined (3-4 cm. long); terminal leaflet (4-8 cm. long) 

 lanceolate to oblong-lanceolate, acuminate, tapering into a long 

 stalk (10-15 mm.), occasionally 3-lobed at base, sharply and sali- 

 ently serrate wath either medium or coarse teeth;" lateral leaflets 



about Vx shorter, less acuminate, more truncate and often very 



oblique at the base: heads on slender ascending peduncles of 

 medium length, rather small (largest about 15 mm. diameter), hem- 

 ispherical or globular ; outer involucral bracts 6-8, spatulate-linear, 

 mucronate, entire, sparsely ciliate, equaling the disk or sometimes 

 twice as long (10-15 mm.); inner bracts brownish, 8-12, oblong, 

 scarcely acute (8 mm. long), apex slightly pubescent ; chaff often 

 reddish-tipped: ray flowers usually present, ligule broadly oval, 

 equaling the disk, golden yellow, caducous, the ovaries narrowly 

 and evenly cuneate, hairy, hairs on the margins in clusters and 

 directed upward, summit convex, awns 2, divergent, scarcely longer 

 than the breadth of the ovary, downwardly barbed : corolla of the 

 disk flowers small (2.5-3 mm.), shorter than the awns, 5-toothed, 

 orange, campanulate-oblong, slightly contracted below, basal por- 

 tion shorter than the upper : stamens exscrted : achencs in fruit 

 (6 X 3.25 mm.) cuneate, slightly contracted at the summit, flattish, 

 costate, nearly black, tuberculate, sparsely hairy, margins upwardly 



hairy to base of awns, summit truncate : awns short O^-^/ length 

 of achene), slender, slightly divergent, strongly downwardly barbed 

 (rarely barbs erect). 



New Brunswick to Florida, westward to Texas and Nebraska. 



Specimens examined from : — New Brunswick : Chalmers {ex 



Macoun). Maine : Parlin ; M. E. Hill, no. 93. New Hampshire : 



*BriUon, Bull. Torr. Bot. Club, 20: 280. 1S93. 



