187 
COMPOSITE. (COMPOSITE FAMILY.) 
21. Baccharis. Pappus soft and capillary, much elongated in the 
fertile flowers. 
•*♦++ Involucres of the fertile and sterile flowers very dissimilar; the 
former closed, 1 -2-flowered ; the latter racemed, flat. 
28. Ambrosia. Fertile involucre seed-like, pointed, 1-seeded. 
29. Xanthium. Fertile involucre burr-like, clothed with hooked 
prickles, 2-celled, 2-seeded. 
* * Heads radiate : the disk-flowers tubular and perfect, rarely ster¬ 
ile : those of the border ligulate, pistillate, or neutral, 
pappus of capillary bristles. Receptacle naked. 
•w-Rays small and inconspicuous so that the head appears discoid, or 
very slender, in several-many rows. (One section of Erigeron 
might be referred here.) 
9. Nardosmia. Heads somewhat dioecious. Flowers purplish or 
whitish. Heads corymbed. 
10. Tussilago. Head (single) with many rows of narrow rays, and 
few disk-flowers, yellow. 
n-*--M-Rays in one marginal row, or nearly so, not yellow (as are mostly 
the disk-flowers). 
= Rays fertile. 
15. Erigeron. Scales of the involucre nearly equal and in one row, 
narrow. Rays very many. Pappus simple or double, not 
copious. 
16. Diplop appus. Scales of the involucre unequal, imbricated. Rays 
8-12. Pappus double, the outer very short. 
13. Sericocarpus. Scales of the top-shaped or club-shaped invo¬ 
lucre closely imbricated, 12 - 15-flowered. Rays about 5. 
Pappus simple. Achenia inversely pyramidal, very silky. 
14. Aster. Scales of the (many-flowered) involucre imbricated. 
Pappus simple. Achenia flattened. 
===== Rays sterile. 
12. Galatella. Involucre imbricated. Rays 3-12. Disk-corollas 
deeply cleft. Achenia silky. 
++++++Rays in one marginal row, yellow, as well as the disk-flowers. 
= Involucre imbricated. 
18. Solidago. Rays few and short. Pappus simple. 
23. Inula. Rays very numerous and narrow. Pappus simple. 
20. Chrysopsis. Pappus double; the exterior short, chaffy-bristly. 
= = Involucre of nearly equal scales in 1-2 rows. 
51. Senecio. Pappus of very soft and slender bristles. Leaves al¬ 
ternate. 
52. Arnica. Pappus of rather rigid almost barbellate bristles. Lea\ es 
opposite. 
