408 Order 7a— COMPOSITE. 



ARTIFICIAL ANALYSIS OF THE GENERA. 



A. Suborder, TUBULIFLOR^. 



S Heads discoid, that is, without rays. (1) 



1 Bec&ptacle naked^ i. e., with no pales or T)ristles among the flowers. (2) 

 2 Pappus a circle of 5— 20 chaflFy scales, (a) 

 2 Pappus none, or a short, toothed margin, (b) 

 2 Pappus composed of many capillary bristles. (3) 

 3 Leaves opposite. (Heads homogamous.) (d) 

 3 Leaves alternate. (4) 



4 Heads homogamous, — fls. all perfect (c) 

 4 Heads heterogamous, fls. not ail perfect. (5) 

 5 Scales herbaceous, often deciduous, (e) 

 5 Scales scarious, persistent, often colored, (f) 

 1 Heceptacle cluiffy beaiiiig pales among the flowers. (6) 

 6 Leaves alternate, (g) 



6 Leaves opposite, (h) 



1 Receptacle bearing brisiles^ or deeply alveolate (honey-combed). (7) 



7 Pappus none, or consisting of scales, (i) 

 7 Pappus composed of many bristles, (j) 



§ Heads radiate, i. e., the outer flowers ligulate. (8) 



8 Jieceptacle naked (not chaffy), or (in No. 6T) deeply Tioneyconib-cMled. (9) 

 9 Pappus of 5-12 scales which are 1-awned or (in No. 61) cleft-bristly. (k) 

 9 Pappus none, or of a few short awns. (1) 

 9 Pappus of many capillary bristles. (10) 

 10 Kays cyanic, in a single row. (m) 

 10 Rays cyanic, in several rows, (u) 

 10 Kays yellow, In about one row. (11) 



11 Pappus double, or of veiy unequal bristles, (o) 

 31 Pappus simple, the bristles all similar. (12) 



12 Involucre scales imbricated, the outer shorter, (p) 

 12 Involucre scales equal, not imbricated, (r) 

 8 Receptaole cliaffy^ with pales among the flowers. (13) 



13 Disk and ray flowers both fertile, the latter pistillate. (14) 

 14 Kays yellow (s) 

 14 Kays cyanic, (t) 

 13 Disk, flowers sterile, ray flowers fertile, (u) 

 13 Disk flowers fertile, ray flowers sterile. (15) 



15 Achenia obcompressed, often beaked, (v) 



15 Achenia compressed laterally, or not at all. (x) 



a Corolla lobes one-sided. Head large, many -flowered Stokesia. 2 



a Corolla lobes one-sided. Heads 4 — 5-flowei-ed, aggregated Eleph astopus. 3 



a Corolla lobes equal — Leaves opposite. Pappus nwned Ageratum. 4 



—Leaves whorled. Pappus obtuse Sclerolepis. 5 



— Leaves alternate. — Pappus scales S — 10 Polypteris. 63 



— Pappus scales 12 — 20 Htaibnopappub. 64 



b Loaves opposite. Flowers dirocions, obscure Ambrosia. 45 



b Leaves alternate. — Flowers yellow. Disk conical I Matricaria, 78 



—Flowers yellow. Disk convex Tana-cetum. 75 



— Flowers whitish. — Erect, leafless above Adknocaulon. 15 



—-Erect, leafy Artemisia. 76 



— Low and depressed Soliva. 77 



O Scales of the involucre in one row. Flowers cyanic. Cacalta. 84 



C Scales of the involucre in one row. Flowers yellow Sbnecio. 86 



C Scales imbricated.— Flowers yellow Bigelovia. 27 



—Flowers whitish. Eupatoeiritm Kuhnia. 8 



—Flowers purple.— Pappus simple Li atkis. 7 



— Pappus double Vernonia. 1 



d Achenia lO-striate. Flowers purple Briokellia. 9 



d Achenia 5-angled.— Keceptacle conical. Flowers blue Conoounium. 12 



— Eecoptacle flat— Scales 4 or 5 Mdcania. U 



— Scales 8 — 20 Eupatobiuu. 10 



