COMPOSITE. 53 



20. XANTHOCEPHALUM. Heads many-flowered, pluriradiate. Involucre broadly 

 campanulate or hemispherical. Receptacle Hat or convex. Ligules usuaUy elongated, 

 numerous. Akenes truncate and naked at summit, or edged with a ring bearing a minute 

 coroniform or squamellate pappus, or none. Heads larger, solitary at t i I The 1 .ranch- 

 lets or in. open cymes. 



21. GUTIERREZIA. Heads few-many-flowered. Imoluere oblong-davate , turbi- 

 nate to campanulate. Receptacle from plane to conical, commonly ;il or fimbnllatc. 

 Style-appendages mostly slender. Ligules 1 to 8. Akenes short, obovate or oblouj 



or Singled. Pappus pluripaleaceous, but the pale* often reduced to a crown or minute, in 

 the ray commonly smaller and sometimes wanting. Heads small, paniculate nr cym 

 clustered. Disk-flowers, or some of the central ones, occasional Iv infertile. 



22. AMPHIACHYRIS. Heads few-many-flowered ; the ray-llowers only fertile; those 

 of the disk hermaphrodite or subhermaphrodite but infertile. Involucre, <K.e'. of Gutu n 

 Style-appendages lanceolate ; the stigmatic lines below them indisiii.ei or obsolete. rYrtilo 

 akeiies pubescent. Pappus of the ray-flowers obsolete or coroniform, or of a few setil'orm 

 squamelhe ; of the disk setiform-paleaceous, \h. of 5 to 20 aristii'orm palea; or weak bristles 

 more or less dilated and united at base, nearly equalling the corolla. 



33. BRACHYCH^ETA. Heads, &c. as iu Solidayo. Pappus both in the ray and disk of 

 bristles abbreviated to squamellas. 



* * Pappus paueiaristate, i. e. of few (less than 10) elongated awns or rigid bristles, some- 

 times caducous or wanting: heads radiate or iu same genus rayiess, solitary at the end 

 of the branches. 



23. GRINDELIA. Involucre many-flowered, hemispherical or at first globose; its 1 i 

 numerous and narrow, imbricated in many series, firm and rigid, with more or l> s h. rbaceous 

 tips. Style-appendages lanceolate or linear. Akenes short and thick, compressed or turgid, 

 or the outer triangular, truncate, glabrous. Pappus of 2 to 8 caducous nearly smooth a\\ us 

 or corneous bristles. 



24. PENTACH.<5CTA. Involucre many-several-flowered, hemispherical or campanulate, of 

 thin and scarious-margined appresscd bracts, destitute of herbaceous tips, commonly tipped 

 with a delicate mucro. Style-appendages filiform-subulate, hispid. Akenes oblong to fusi- 

 form-obovate, somewhat compressed and villous. Pappus of mostly 5 (rarely 3 to <; or 

 even 12) slender and persistent seal irons bristles with somewhat cnlaiged base, sometimes 

 reduced to this base, or even this obsolete. Receptacle short-alveolate. Rays either yellow, 

 or white or pink ! 



* * * Pappus multisetose in either the disk or ray, but not in both, and akeiies of disk 

 and ray unlike. 



25. BRADBURIA. Involucre campanulate, of rather broad and thin scariously margined and 



mucronatc-acuminate appressed bracts. Hay-flowers about 12, fertile; the style \ery short. 

 Disk-flowers about the same number, infertile; their style-branches destitute of stigmatic. 

 Hues, filiform, barbellate-hispid. Akenes of the ray sparsely villous, trigonal-turbinate with 

 a strong rib at each angle; the pappus of numerous unequal rigid capillary bristles, little 

 longer than the akene : those of the disk abortive, with pappus of very few (usually 2) bristles 

 which are somewhat chaffy-dilated at base. 



26. HETEROTHECA. Involucre hemispherical or broadly campanulate, of narrow rather 

 rigid bracts. Receptacle alveolate. Ray- and disk-flowers numerous, both fertile, 

 branches of the hermaphrodite flowers tipped with a lanceolate or sometimes (in the same 

 species ''. } ovate-triangular appendage. Akenes of the ray thickisli, often t riangular, with no 

 pappus or an obsolete crown, rarely a bristle or two; of the disk compressed, sericeous- 

 hirsute, and with a double pappus; the inner of copious and long capillary scabrous bristles, 

 outer of numerous short and stout bristles or setiform squamellse. 



* * * * Pappus multisetose and double, both in disk and (when present) in the ray ; the 

 inner capillary; outer very short and setulose or squamellate. 



27. CHRYSOPSIS. Heads many-flowered, with rays-numerous, or rarely wanting. In- 

 volucre campanulate or hemispherical, of narrow regularly imbrieaied bracts. 

 appendages from linear-filiform to slender-subulate. Akenes compressed, but often turi; 

 from obovate to linear-fusiform. Principal pappus of numerous capillary scabrous bristles ; 



