Genus 71. 



THISTLE FAMILY 



Beggar-ticks. 



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

 Small Beggar-ticks. Fig. 4510. 



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

 B. discoidea Britton, Bull. Torr. Club 20: 2S1. 1893. 



Annual, glabrous, slender, branching, erect, 2'-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 



7. Bidens frondosa L 



Stick-tight. Fig. 451 1. 



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

 B. melanocarpa Wiegand, 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'-l' wide; heads usually numerous, 

 long-peduncled, about 6" high, 5"-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, z"-$" 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"-z\" 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 



