SYNANTHEREJi!. 373 



acuminste, blimtisli at the base, minutely liispiduloua ; involucre loose, subrecurved : exfeHor 

 scales fohaceous, oblong-lanceolate, pointed, somewhat exceeding the ray; palese incurved- 

 mucronate, obovate-oblong.— Tbe determination of this species rests only on DCs incom- 

 plete diagnosis.— Exterior scales of the involucre 6"' long ; Hgules 8-10, oblong, 2-dentate 

 httle longer than the disk.— Hab. Dominica !, 7)Kr. ; [Cuba]. 



32. BIDENS, L. 



Je«<^radiate or discoid: the ray-flowers sterile. Involucre k-scn&l. Receptacle isitish, 

 paleaceous : paleffi deciduous with the acheuium. Style-branches hispidulous above, acute. 

 Achemum compressed or tetragonal, 2-4(-6)-awued : awns persistent, retrorsely hispid.— 

 Leaves opposite, serrate or divided; heads corymbose or single, yellow or white. 



Sect. PsiLOCARP^A, DC. — Achenium tetragonal, linear, tapering above. 



• 103. B. leucanthus, W. Annual, glabrous or nearly so ; stem erect, tetragonal; 

 leaves pinnatisect, 1-3-jugal (rarely simple) : segments uvate-laneeolate or ovate, acumi- ^ 

 nate; heads corymbose: ray white or none ; exterior involucral scales appressed, lanceo- I 

 late, ciliate or puberulous ; achenia glabrous or Tiispidulous above 1 awns 2-4, diverging in / 

 the exterior, erect in the central larger ones. — Desc. M. 8. t. 583. — Coreopsis, L. B. pilo- (^ 

 sus, L. : the discoid form. B. brachycarpus and anthriscoides, DC. Coreopsis coronata, L. 

 {ex Plum. Md. Burm. t. 53./. 2), and C. alba, L. {ex Berm. Farad, t. 124).— A remark- 

 able form, with all leaves simple, hispidulous achenia, and whitish-pubescent involucres, was 

 collected by Dr. Alexander, but transitions into the common B. leucanthus occur among 

 Mr. March's speci;mens. — Hab. Jamaica !, all coll., a common weed; Antigua I, WuUschl.; 

 Trinidad 1, Seh., Or. ; [Florida ; Cuba ! and Mexico ! to Brazil 1 and Chili ! ; Pacific islands ! 

 to trop. Australia I, New Zealand I, and East Indies ! ; Madeira I, trop. Africa 1 to the Cape !]. 

 104. B, Coreopsidis, DC. Stem herbaceous, scandent, cylindrical ; leaves pinnati- 

 sect, l(-2)-jugal, superior often, all rarely simple : segments ovate-lanceolate or oblong-lan- 

 ceolate, acuminate ; heads corymbose : ray yellow ; exterior involucral scales squarrose- -. 

 spreading, linear ; achenium hispidulous on two margins, or glabrescent : awns 2 (-4), di- 

 verging. — Sm. Spicil. t. 22 ; Bot. Beg. t. 7. — Coreopsis reptans, L. C. incisa, KeT, C. 

 chrysantha, L. {Plum. Ed. Burm. t. 53./. 1), is perhaps a form with smaller ligules. B. 

 tereticaulis, DC. .- the common, glabrous form. B. squarrosus, Kth. : a hairy variety, with 

 the leaves densely pubescent beneath. B. speciosus, Gardn. ! — Lignles large, usually entire 

 at the top. — Hab. Jamaica!, aU coll., in waste places; Autigua!, Nichols., WuUschl., 

 S. Vincent !, G-uild. ; [Texas ! and Cuba ! to Brazil !]. 

 X 105. B, bipinnatus, Z. Annual, glabrous ; stem erect, tetragonal ; leaves 2-Z-pin- 



' natisect (rarely simply pinnatisect): segments small, cnueate-oblong or lanceolate; heads ^ 

 long-peduncled : ray-jlowers few, yellow, subincluded ; exterior involucral scales spreading, * 

 linear ; achenium long, glabrous or hispidulous above : awns 4-2, snberect or little diver- 

 ging. — B. cynapiifolius, Kth. B. portoricensis, Spreng. B. parviflorus, W. : ex specim. 

 Turczan.— Hab. Jamaica {Lun.) ; Antigua !, WuUschl., a weed ; [Connecticut and Cali- 

 fornia 1 to Buenos Ayres 1 ; Southern Siberia !; Southern Tirolia ! to trop. Africa !], 



33. COSMOS, Cav. 



Character of Bidens, but awns of the beaked achenium deciduous or abortive. — Leaves 

 ^^pinnatisect ; heads radiate, long-peduncled. 



106. C. caudatus, Kth. Glabrous or nearly so ; leafrsegments lanceolate, scabrous on .- 

 the margin ; exterior involucral scales nearly as long as -tlie inner series ; ray rosy ; ache- I 

 nium tapering from the middle into an upwardly scabrous beak : awns 2, horizonfed. — 4'-7' 

 high ; achenium (the beak included) 10"'-12"' long. — Hab. Jamaica !, Bancr., Wils. ; 

 Antigua !, WuUschl., Dominica !, Imr., S. Vincent !, Guild. ; Trinidad I, Sch. ; [Key West, 

 Cuba I and Mexico 1 to Ecuador 1]. 



107. C. Bulfureus, Cav., var. leiorbynclius, Gr. Glabrous or nearly so : leaf-seg- _ 

 ments lanceolate, scabrous on the margin ; exterior involucral scales linear, exceeded by the j 

 inner lanceolate ones ; ray yellow ; achenium longer than its beak : awns abortive (in a 



