232 THE FLORA. 



Analysis of the Genera. 



Sub-order First, TUBULIFLOR^, 



having all the perfect flowers tubular (§ 05), the ligulate flowers, if any, imperfect. 



§ Heads of flowers radiate, with yellow rays. . . .2 



§ Heads of flowers radiate, the rays not yellow. . . .8 



§ ]Jead8 of flowers discoid (no rays). These genera, about 50 in number, such as 

 the Tansy, Wormwood, Bonesei, Jronweed (Figs. 248-250), Everlasting, Burdock 

 (Fig. 509), Thistle, Hogweed (Fig. 514), and even Bachelor'' s-hutton, are all, for 

 want of room, omitted. (See Class Book of Botany, p. 410, &c.) 



2 Leaves alternate or scattered on the leafy stems. . . .4 



2 Leaves opposite or whorled on the stems, or all radical 6 



3 Leaves alternate or scattered on the leafy stem. . . .7 

 3 Leaves opposite or whorled on the leafy stem....x 

 3 Leaves all radical and the flowers on a scape y 



4 Eeceptacle chafi"y (with bracts growing among the florets) ... .5 



4 Eeceptacle with deep, horny cells, like a honeycomb,.., e 



4 Eeceptacle not cliafi"y, flat or merely convex a 



4 Eeceptacle not chafi'y, conical or globular. . . .f 



5 Eays sterile, disk fertile. Eeceptacle conical or columnar. . . .g 



5 Eays sterile, disk fertile. Eeceptacle flattish. Fruit flattened on the sides. . . .h 



5 Eays fertile, disk sterile. Eeceptacle flat. Fruit flattened same way as scales . . . .* 



6 Eeceptacle chafi'y. Eays sterile, disk fertile o 



6 Eeceptacle chafi'y. Eays fertile, disk sterile p 



6 Eeceptacle chaffy. Eays fertile, disk perfect q 



6 Eeceptacle naked or destitute of chafi'y scales m 



7 Eeceptucle not chaffy, naked of scales 8 



7 Eeceptacle chafi'y with scales among the florets. Lvs. finely divided. . . .v 

 7 Eeceptacle chaffy with scales, &c. Lvs. undivided, merely toothed.... w 



8 Pappus of numerous bristly hairs ... .9 



8 Pappus of 2 or 3 awns and minute hairs. Glabrous plants t 



8 Pappus wholly wanting, or only a membranous margin. . . .u 



9 Involucre of unequal scales, imbricated in several rows 10 



9 Livolucre scales nearly equal, narrow, and almost in one row....t 



10 Pappus simple, the bristly hairs abundant and about equal r 



10 Pappus double, the outer row of hairs extremely short s 



a Involucre scales imbricated in several rows b 



a Involucre not imbricated, the outer scales very short or none Sene'cio. 

 a Invol, not inibr,, ouf er scales equal to the inner. Marigold. Calen^dula. 

 a Involucre not imbricated, outer scales longer than inner. S. Gaillar'dia 



b Pappus simple, the bristles all equal and of one kind o 



b Pappus double, the outer very short and cliaffy. Lvs. entire, W, S, CHRysop''8i3 



b Pappus double in the disk, none in the rays. Lvs. toothed. S, Heterothe'ca 



