GENUS 71. 



THISTLE FAMILY. 



497 



6. Bidens discoidea (T. & G.) Britton. 

 Small Beggar-ticks. Fig. 4510. 



Coreopsis discoidea T. & G. Fl. N. A. 2 : 339. 1842. 

 B. discoidea Britton, Bull. Torr. Club 20: 281. 1893. 



Annual, glabrous, slender, branching, erect, 2 r -6 

 high. Leaves membranous, very slender-petioled, 

 all the lower ones divided into 3 lanceolate or 

 oblong-lanceolate, dentate, acuminate segments 

 which are i'-3' long; uppermost leaves commonly 

 rhombic-lanceolate and undivided; heads usually 

 numerous, slender-peduncled, 2"-4" broad and 

 about as high; involucre broadly campanulate or 

 hemispheric, its outer bracts mostly 4, usually 

 foliaceous and obtuse, usually much surpassing 

 the inner ones ; rays apparently always wanting ; 

 achenes flat, narrowly cuneate, upwardly strigose, 

 about 2" long; pappus of 2 short, upwardly his- 

 pid, rarely downwardly barbed awns. 



In swamps and wet places, Massachusetts to Vir- 

 ginia, Ohio, Michigan, Louisiana and Texas. July- 

 Sept. 



I \ 1 ^71 



7. Bidens frondosa L. Beggar-ticks. 

 Stick-tight. Fig. 4511. 



Bidens frondosa L. Sp. PI. 832. 1753. 

 B. melanocarpa VViegand, Bull. Torr. Club 26: 405. 

 1899. 



Annual ; stem erect, branched, glabrous, or 

 nearly so, often purplish, 2-3 high. Leaves thin, 

 but not membranous, slender-petioled, pinnately 

 3-5-divided or the uppermost undivided, the seg- 

 ments lanceolate or oblong-lanceolate, sharply 

 serrate, acuminate at the apex, narrowed at the 

 base, usually slightly pubescent beneath, stalked, 

 2'-4' long, i'-i' wide ; heads usually numerous, 

 long-peduncled, about 6" high, s"-io" broad; in- 

 volucre campanulate, becoming hemispheric, its 

 outer bracts 4-8, more or less foliaceous, often 

 much exceeding the ovate-lanceolate, scarious- 

 margined inner ones ; rays none or rudimentary 

 and inconspicuous; disk-corollas orange; achenes 

 flat, narrowly cuneate, nearly black, 3" -5" long, 

 ciliate, the two slender awns downwardly barbed, 

 or sometimes upwardly hispid. 



In moist soil, often a weed in fields, Nova Scotia to Florida, British Columbia, Texas, Colorado 

 and California. Introduced as a weed into southern Europe. Rayless marigold. Beggar-lice. 

 Devil's-pitchfork. Stick-seed. Common bur-marigold. 

 Old-ladies clothes-pins. Cuckles. July-Oct. 



8. Bidens vulgata Greene. Tall Beggar-ticks. 

 Fig. 4512. 



Bidens vulgata Greene, Pittonia 4: 72. 1899. 

 B. frondosa puberula Wiegand, Bull. Torr. Club 26 : 408. 

 1899. 



Taller, sometimes 9 high, glabrous or nearly so, 

 or crisp-pubescent above. Leaves pinnately 3-5- 

 divided, the veins straight and prominent ; heads 

 larger, 7"-i2" broad, stout-peduncled ; outer invo- 

 lucral bracts linear to linear-spatulate, ciliate, the 

 inner mostly ovate or narrowly triangular, pubescent 

 at apex ; ray-flowers usually present, small, yellow ; 

 achenes very flat, 3"-4$" long, 2"-2i" wide, brown 

 or greenish brown, the margins downwardly barbed 

 above, upwardly hairy below ; awns 2, half as long 

 as the achene or more, downwardly barbed. 



In moist soil, Quebec to British Columbia, New York, 

 North Carolina, Missouri, Colorado and California. 

 Aug.-Sept. Included in the preceding species in our 

 first edition. 



32 



