COMPOSITE. 293 



* Receptacle elongated, becoming columnar. 



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



* * Receptacle flat, convex, or rarely conical. 

 HH Rays pistillate and fertile. 



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



i]uadrangular or somewhat compressed. 



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



the prismatic-(|uadrangular or compressed akene, persistent, irregularly cleft into 5 or 

 more lobes or teeth, those on the angles sometimes elongated into rigid chaffy awns. 



46. Verbesina. Pappus 2 slender or small awns ; the flat akene margined by a broad wui'', at 



least in the disk-flowers. ° 



Hs- -}- Rays neutral, or rarely none. 



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



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



48. Helianthella. Akenes flat and the thin edges more or less margined : pappus a pair of per- 



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

 chaffy scales. 



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



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

 convex. 



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



cle convex or conical. 



Subtribe III. COREOPSIDE^. Heads as in the preceding subtribe, except that the chaff 

 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 cliaff" 

 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 ciliate : 



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



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



nute cup. 



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



Subtribe IV. GALINSOGE^. Heads, &c., as in subtribes II. and V. Akenes neither com- 

 pressed nor obcompressed. Pappus in both ray- and disk-flowers of numerous chaffy scales 

 or awns (rarely nearly none). See one exceptional Hemitonia, 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, occasionally 

 nearly or wholly wanting. 



Subtribe V. MADIE^E. Heads heterogamous, mth 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 less a ray-akene, sometimes a few outer and empty or 

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

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

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

 mally some rudiments in a few cases), composed 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 carinate strongly in- 



folded scales of the involucre, which therefore becomes deeply sulcate. 



55. Madia. Pappus none, or of some 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 scales of the involucre rounded on the back. 



56. Hemizonella. Involucre strongly 4 - 5-sulcate (in the manner of Madia) by the complete 



enwrapping of the 4 or 5 akenes. Disk-flower one, fertile, in a .sort of interior involu- 

 cre : ]iappus none. 



57. Hemizonia. Involucre many - few-flowered, less if at all sulcate or lobed ; its scales at 



base half-enclosing the obovate or somewhat triangular ray-akenes. Disk-flowers numer- 

 ous or few, all or some of them infertile : pappus of chaffy scales or none. 



