260 COMPOSITE. (COMPOSITE FAMILY.) 



Less.} Penn. to Michigan, Illinois and southward. Aug. - Sept. Heads ex- 

 haling the odor of anise when bruised : disk turning brownish. 



* * # # Achenia wingless, flat, 2-awned, 2-toothed, or rarely truncate, l-nerved or 

 ridged on each face : scales of the outer involucre leafy, rejlexed or spreading : 

 leaves opposite, petioled, generally pinnately or ternately compound, the leaves or 

 leaflets serrate : biennials or annuals, with the aspect of Bidens, intermediate be- 

 tween that genus and Coreopsis; and certain ambiguous (hybridized?) speci- 

 mens, with the awns barbed some upwards and some downwards, connect the two. 

 H- Rays conspicuous, golden-yellow. 



9. C. aristbsa, Michx. Somewhat pubescent; leaves 1 - 2-pinnately 5- 

 7-divided, petioled ; leaflets lanceolate, cut-toothed or pinnatifid ; heads panicled- 

 corymbose; outer involucre of 10-12 leafy bracts; achenia obovate, often ob- 

 scurely wing-margined, bristly-ciliate, with 2 (rarely 4) long and slender diverging 

 awns as long as the achenium itself. Swamps, Ohio to Michigan, Wisconsin, 

 and southwestward. Aug. - Oct. Var. MtrriCA has two short divergent teeth 

 or points in place of the awns. W. Illinois and southwestward, where a form 

 (C. involucrata, Nutt.) occurs with the bracts of the outer involucre more leafy, 

 numerous, and hirsute. Mr. Fritchey sends, from near St. Louis, specimens with 

 short awns and their barbs either spreading or retrorse, and others with long 

 awns retrorsely barbed, perhaps hybrids with some Bidens. 



10. C. trichosp^rma, Michx. (TICKSEED SUNFLOWER.) Smooth, 

 branched ; leaves short-petioled, 5 - 7-divided ; leaflets lanceolate or linear, cut- 

 toothed, or the upper leaves only 3 - 5-cleft and almost sessile ; heads panicled- 

 corymbose ; achenia narrowly wedge-oblong or the inner ones wedge-linear, smooth or 

 minutely appressed-hairy, marginless, crowned with 2 erect triangular or awl-shaped 

 stout teeth. Swamps, Massachusetts to Virginia near the coast. Also Buffalo, 

 New York (G. W. Clinton), and Illinois ( Vasey), where forms with shorter 

 achenia approach the Southern C. aurea. Aug. - Oct. 



* Rays none, or rarely small and inconspicuous: outer involucre of few (usually 

 3-5) loose leafy bracts commonly surpassing the heads: achenia minutely ap- 

 pressed-pubescent : plants glabrous, l-3 high. 



11. C. discoidea, Torr. & Gr. Diffusely branched; leaves ternately di- 

 vided, slender-petioled ; leaflets ovate-lanceolate, pointed, coarsely serrate ; heads 

 2" -3" long; achenia linear-wedge-shaped (2" -3" long), bearing a pair of short 

 and stout upwardly-barbed awns of the length of the corolla. Wet banks and 

 swamps, Delaware ( W. M. Canby) to Ohio, Illinois, and southward. July. 



Anomalous specimens, from near Philadelphia (A. H. Smith, &c.), growing 

 with Bidens frondosa, differ from small forms of that only in the less rigid and 

 upturned barbs of the awns. 



12. C. bidentoides, Nutt. Pan iculately branched ; leaves undivided, lan- 

 ceolate, coarsely toothed, taper-pointed, and the base tapering into a slender pet- 

 iole; heads 6"- 10" long; achenia nearly subulate tapering downwards, bearing a 

 pair of very slender upwardly roughened awns surpassing the corolla (4" long), but 

 shorter than the achenium, often also 2 minute teeth alternate with the awns. 

 Shores of Delaware River, near Philadelphia, and in Delaware, Nuttall, Durand, 

 A. H. Smith, W. M. Canby. 



