Bidens.'] lxxviit. compositj:. (J. D. Hooker.) 309 



60. BIDENS, Lmn. 



Annual or perennial, sometimes climliing herbs. Leaves opposite, entire 

 toothed gashed or 1-2-pimiate. Heads corymbosely pamicled or suhsolitary, 

 heterogamous and rayed or homogamous and disciform ; ray-fl., if present, $ or 

 neuter, 1-seriate, ligule spreading yellow or white ; disk-fl. ^ , fertile, tubular, 

 limb cylindric 5-fid. Involucre campanulate or hemispheric ; bracts sub- 

 S-seriate, bases connate, outer herbaceous short or leafy, inner membranous ; 

 receptacle flat or convex, pales narrow nearly flat. Anther-cells entire or sub- 

 sagittate. Style-m-mg of y hairy above, tips short acute or long and subulate. 

 Achenes 4:-gonous or dorsally compressed, linear or cuneiform, often narrowed 

 but not beaked above ; pappus of 2-4 rigid, retrosely hispid bristles or 0. — 

 DisiElB. Species about 60, chiefly American. 



• Achenes cuneiform, tip truncate. 



1. B. cemua, Idnn.; Boiss. Fl. Orient, lii. 250; leaves undivided serrate 

 bases subconnate, heads drooping, outer invol. bracts leafy, inner ovate, achenes 

 with 1-4 short awns or 0. Clarke Comp. Ini. 140. 



■Westeen Himalaya; Kashmir and Chumba, alt. 5-6000 ft., rare, Thomson. — 

 DisTRiB. N. Asia, N. and mid. Europe, N. Ameriea. 



Annual, stout, erect, glabrous. Leaves 3-S in., base sometimes auricled. Heads 

 'jl-\ in. diam. ; inner invol. bracts broad, membranous, pale brown ; lignlee in 

 Indian specimens. Achenes very variable, euneate, compressed, margins sometimes 

 thickened and armed with short recurved spines. 



2. B. tripartita, Linn. : Boiss. Fl. Orient, iii. 261 ; leaves 3-lohed 

 3-partite or pinnatifld, segments lanceolate toothed, heads erect solitary discoid, 

 outer invol. bracts herbaceous, inner oblong with scarious margins, achenes with 

 2-3 short awns. Clarke Cemp. J«rf; 140. B. repens. Den Predr. 180; DC. 

 Prodr. V. 695; Watt. Cat. 3187, A.; aarke Comp. Ind. 140. B. trifida, Boxh. 

 Fl. Ind. iii. 411. B. frondosa, Herb. Ham. 



Centhai and Western Himalaya, in marshes, alt. 3-5000 ft., from Nipal to 

 Kashmir. Western Tibet; Iskardo, Thomson. — Bistrjb. N. Asia, Japan, and 

 westwards to N. Africa, W. Europe and N. America. 



Stout, annual, erect, 1-3 ft. high, glabrous. Leaves 3-5 in. Heads f in. diam., 

 peduncles long or short ; outer invol. bracts exceeding the inner. Achenes \ in., 

 glabrous ; awns very short, 



** Achenes long, slender, narrowed from the middle to the top. 



3. B. pilosa, Lmn.; glabrous er hairy, leaves 3-fld 3-foliolate or 1-2- 

 pinnatifld, achenes j-§ in. 



Throughout India, ascending the Himalaya and other mountains to 6000 ft. — 

 Distrib. All warm countries. 



A very variable, erect, glabrous pilose or pubescent herb, 6-24 in high, a well- 

 known pest from the adhesion of its barbed achenes to the garments and body. 

 Leaves excessively variable. Heads on long stout peduncles, very variable in length, 

 with or without white or yellow rays ; invol. bracts with broad scarious margins. 

 Achenes black, much exceeding the involucre, very slender, with 2-4 short, stout, 

 spinescent awns covered with recurved hooks. 



Var. 1. pilosa proper ; leaves 3-fid or 3-sect., segments broadly or narrowly ovate 

 or lanceolate serrate. B. pilosa, lArm. ; DC. Pros', v. 597 ; Clarke Comp. Ind. 140. 

 B. leucantha, Willd. B. chinensis, Willd; Wall. Cat. 3189, A. B.C. B. tripartita 

 and B. bipinnata, Wall. Cat. 3187, B. C. D. 



Vab. 2. bipinnata ; leaves bipinnatifidly compound, segments ovate lanceolate or 

 linear entire lobed or toothed. B, bi,pinna1ia, ii»n. ; Roxb. Fl. Ind. iii. 411. R 



