COMPOSITE. 63 



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

 campanulate or hemispherical. Eeceptacle flat or convex. Ligules usually elongated, 

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

 coroniform or s(iuam€llate pappus, or none. Heads larger, .solitary at the end of the branch- 

 lets or in open cymes. 



21. GUTIERREZIA. Heads few-mauy-flowered. Involucre oblong-clavate or turbi- 

 nate to campanulate. Receptacle from plane to conical, commonly alveolate or fimbrillate. 

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

 or 5-angled. Pappus pluripaleaceous, but the palete often reduced to a crown or minute, in 

 the ray commonly smaller and sometimes wanting. Heads small, paniculate or cymo.se- 

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



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

 of the disk hermaphrodite or subhermaphrodite but infertile. Involucre, &c. of Gutierrezia. 

 Style-appendages lanceolate ; the stigmatic lines below them indistinct or obsolete. Fertile 

 akenes pubescent. Pappus of the ray-flowers obsolete or coroniform, or of a few setiform 

 squamelkL' ; of the disk setiform-paleaceous, viz. of 5 to 20 aristiform paleai or weak bristles 

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



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

 bristles abbreviated to squameUae. 



* * Pappus pauciaristate, i. e. of few (le,ss than 10) elongated awns or rigid bristles, some- 

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

 of the branches. 



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

 numerous and narrow, imbricated iu many series, firm and rigid, with more or less herbaceous 

 tips. Style-apf>endages lanceolate or linear. Akenes short and thick, compres.sed or turgid, 

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

 or corneous bristles. 



24. PENTACH.^TA. Involucre many-several-flowered, hemispherical or cani])anulate, of 

 thin and scarious-margined appressed bracts, destitute of herbaceous tips, comuKmly tijjped 

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

 form-obovate, some^vjiat compres.sed and ■villous. Pappus of mostly 5 (rareh^ 3 to 6 or 

 even 8) slender aud persistent scabrous bristles with somewhat enlarged base, sometimes 

 reduced to this base, or even this obsolete. Eeceptacle short-alveolate. Kays either yellow, 

 or white or pink ! 



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

 and ray unlike. 



25. BRADBURIA. Involucre cam'panulate, of rather broad and thin scariously margined and 

 mucronate-acuminate appressed l)racts. Ray-flowers about 12, fertile ; the style very short. 

 Dislv-flowers aliout the same number, infertile ; their style-branches destitute of stigmatic 

 lines, filiform, barbellate-hispid. Akeues of the ray sparsely villous, trigonal-turbinate with 

 a strong rib at eacli angle ; the pappus of numerous unequal rigid capillary l)ristles, 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. Style- 

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

 species ]) ovate-triangular appendage. Akenes of the ra}' thickish, often triangular, 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 squamellie. 



* * * * 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 cam]imiulate or hemispherical, of narrow regularly imbricated bracts. Style- 

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

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



