Ordeb 70.— OOMPOSITj®. 409 



eShrnbs, Flower dicecious, the 9 and $ In different heads BiccnAEB. 85 



e Herbs. — Stem winired. Heads splcate Pteeocaulon. 3G 



— Stem wingless.— Heads coryrabons, purplish Pluchea. 84 



—Heads paniculate.— Pappus reddish Conyza. 82 



— Pappus white Errchtites. 83 



f Eoceptaclo chaffy except in the center Filago. 80 



f Receptacle naked.— Heads dioecious Axtennaria. 7Q 



— Heads heterogamous. — Involucre erect Gnapiialium. 78 



—Involucre radiate Heliciirtsum. 82 



g Scales dry, fadeless. Pappus of scale-like awns Xekantuemum. 81 



g Scales herbaceous. — Flowers diosolous. Fruit a burr Xantdium. 46 



— Fls. all perfect.— Pappus of 5 or C scales Makshallia. 68 



— Papp. of many bristles C akpuepuoeus, 6 



h Flowers yellow. Pappus 2 inversely hispid awns Bidens. 53 



h Flowers yellow. Pappus 2 erectly hispid awns Coeeopsis. 57 



h Flowers whitish, — dicecious. Anthers yellowish Ambrosia. 45 



— menoecious. Anthers yellow Iva. 44 



— all perfect. Anthers black Melantuera. 47 



i Outer scales of the invol. leafy. Pappus none Garth amus. 93 



i Outer scales pectinate or ciliate-fringcd Centaurea. 91 



i Outer and inner scales obtuse, entire Ambeeboa. 92 



J Pappus plumous. Achenia obovato Cynara. 83 



J Pappus plumous. Achenia oblong Ciesium. 96 



j Pappus scabrous, — triple, each row by 10s Cmious. 94 



— simple.— Scales spinescent Onoporoon. 95 



— Scales hooked Lappa. 97 



k Leaves opposite. Papp. sciles deeply cleft into bristles Dybodta. 61 



k Leaves alternate. — Rays fertile Hrlenium. 65 



— Hays sterile. — Receptacle naked or fimbriate Gaillardia. 62 



— Receptacle areolate, Leptopoda. 66 



— Receptacle deeply-celled Baldwikia. 07 



1 Leaves opposite. Involucre double, outer 8 united Dahlia. 23 



1 Leaves opposite. Involucre single ; scales united Tagetes. 89 



1 Leaves alternate. — Pappus of a few short awns or bristles Boltonia. 24 



— Pappus a membranous margin Matricaria. 73 



— Pappus 0. — Rays fertile, disk sterile Calendula. 90 



— ^Fls. all fert. — Invol. scales equal Bellis. 22 



— Invol. broad^ flat Lrucantiieucm. 72 



— Invol. hemispherical Chrysanthemum. 74 



m Eays nutral, sterile, 3—12 ; Pappus simple Galatella. 16 



m Rays pistillate, fertile, — about 5. Achenia very silky Seeigocaepits. 17 



— 8 — 12. Pappus double Diplcpappub. 19 



— 5—75. Pappus simple Abtee. 18 



— 4C — 200, white. Scales equal Erigeeon. 20 



n Flowers dioecious, purplish. Leaves all radical Nardosmia. 14 



n Fls. all fertile. — Outer pappus or very short bristles Erigeron. 20 



—Outer pappus a crown of short, pointed scales Callistepiius. 21 



o Flowers of the disk mostly sterile. Eays 80—40 Pkionopsis. 29 



o Fls, all fertile.— Pappus double in tho disk, none in the ray Heterotheoa. 30 



—Pappus double in both disk and ray Cheysopsis. 31 



p Heads large, about 20-rayed. Pappus in one row Ikula. 8S 



P Heads very small, 1 — 15-rayed. — Pappus 1 row, shorter than achenia.. .Erachtch^t a, 25 

 — Pappus 1 row, tawny, longer than achenia..IsoPAPPu8. 28 



— Pappus irregularly 2-rowed, white Solidaco. 26 



r Head solitary, on a scape with alternate bracts Tussilago. 13 



r Heads corymbed, &c. — Leaves nlteniate ^ Senecto.86 



—Leaves opposite Arnica. 87 



3 Shrubby. Pappus 4-toothed, obscure Boericiiia. ST 



S Herbaceous. — Scales (the 4 outer) united into a cup Tetragonothbca. 50 



— Scales distinct.— Achenia 4-angled. Pappus Heliopbis. 49 



— Achenia flattened. Pappus Acmella. 69 



— Ach. flat, with a 2-awned pappus Veebesina. 60 



