composite. 293 



* Receptacle elongated, becoming columnar. 



43. Rudbeckia. Rays neutral, or very rarely none. Akenes quadrangular and compressed. 



« * Receptacle flat, convex, or rarely conical. 

 +■ Rays pistillate and fertile. 



44. Balsamorhiza. Pappus none. Akenes of tlie ray obcompressed, of the disk prismatic- 



quadrangular or somewhat compressed. 



45. Wyethia. Pappus a clialfy-coriaceous crown or cup, continuous with the broad summit of 



the prismatic-quadrangular or compressed akene, persistent, irregularly cleft into 5 or 

 more lobes or teeth, those on the angles sometimes elongated into rigid chall'y awns. 

 40. Verbesina. Pappus 2 slender or small awns ; the flat akene margined by a broad wing, at 

 hast in the disk-flowers. 



+- +- Rays neutral, or rarely none. 



17. Encelia. Akenes flat and thin-edged but marginless, strongly villous-ciliate : pappus none 

 or a pair of awns, but no intermediate little scales. 



4S. Helianthella. Akenes Bat and the thin edges more or less margined : pappus a pair of per- 

 sistent awns or chaffy teeth, and a crown of intermediate (sometimes very minute) thin 

 chaff; scales. 



40. Helianthus. Akenes thick, quadrangular-compressed or with the sides convex, the edges 

 obtuse : pappus a pair of caducous chaffy scales or awns. Receptacle Bat or merely 

 convex. 



50. Viguiera. Akenes of ITclianlhzcs : pappus with chaffy scales between the awns. Recepta- 



cle convex or conical. 



Subtrihe III. COREOPSIDE.E. Heads.as in the preceding subtribe, except that the chair 

 of the receptacle is flat or barely concave, and mostly deciduous with the fruit. Akenes all 

 obcompressed, i. e. flattened parallel with the subtending scales of the involucre and chaff 

 of the receptacle : pappus of 2 to 4 awns or teeth from the angles, or none. Involucre in 

 our genera double, the outer loose and more or less foliaceous. 



51. Pugiopappus. Rays pistillate, perhaps sometimes neutral. Akenes long-villous or filiate : 



pappus of 2 large and bayonet-shaped naked chaffy awns. 



52. Leptosyne. Pays pistillate. Akenes naked, winged or margined : pappus none or a mi- 



nute cup. 

 58. Bidens. Rays neutral or none. Pappus of 2 to 4 rigid retrorsely barbed awns. 



Subtrihe IV. GALIXSOGEJE. Heads, &c, as in subtribes II. andV. Akenes neither com- 

 press* d nor obcompressed. Pappus in both ray- and disk-flowers of numerous chaffy scales 

 or awns (rarely nearly none). See one exceptional fli mis mia, No. 57. 



54. Blepharipappus. Head rather few-flowered ; the rays pistillate. Akenes turbinate : pap- 



pus of 12 to 20 narrow and thin cut-fringed scales having a strong midrib, tonally 



nearly or wholly wanting. 



Subtribe V. MAf'IK.K. Ilea. Is heterogamous, with ray-flowers fertile: those of the disk 

 either perfect and fertile- or sterile ; rarely the ray-flowers wanting. Involucre a series of 

 scales, each enclosing more or les. a ray-akeno, sometimes a few miter and empty or 

 bracteal scales. Receptacle chaffy only at the margin, the chaff forming a sorl of interior 



involucre, or else subtending either s - or all of the disk-flowers. Style-branches of the 



latter terminated by a Bubulate hispid tip. Pappus none for the ray-akenes (or abnor- 

 mally some rudiments in a few omposed of several awns or chaffy scales or else none 

 in the disk-flowers. Herbs mostly glandular and viscid, and heavy-scented : upper leaves 

 alternate, the lower or lowest opposite. 



• Akenes all laterally compressed, those of the ray wholly enclosed in the earinato strongly in- 



folded scales nf the involucre, which therefore hecomos deeply silicate. 



55. Madia. Pappu none, oi oi small scales in the sterile flowers of one section. 



• < Ray-akenes turgid, more or less oblique or incurved, never laterally compressed, but mostly 



rather obcompressed ; the investing Bcales of the involucre rounded on the bai k. 



56. Hemizonella. Involucre strongly i 5-snlcato (in the manner of Madia) by tl mploto 



■ ii « lapping of the i "i 6 akenes. Disk-flowei one, fortilo, in a sorl of interior Involu- 

 te : pappus none. 



•"■7. Hemizonia. Involucre many few-flowered, h-^-. if at all Bulcate or lobcd ; il 



baa half-enclosing tin tewhat triangiilai i Disl Howors numer- 



ous or lew, all or some ol them infertile : pappus ol chafl i none. 



