SUNFLOWER FAMILY 
157 
Leaves chiefly opposite; heads large; pappus of rather rigid and strongly 
roughened bristles.29. Arnica. 
Leaves alternate ; heads large or small; pappus of abundant soft hairs. 
30. Senecio. 
2. Receptacle covered with bristles; anthers mostly caudate at the base; plants 
thistle-like, zvith alternate prickly leaves; heads large; involucral bracts im¬ 
bricated, usually prolonged into a spine or bristle, or with membranous edges; 
flowers conspicuous; rays none; corolla tubular, deeply cleft; style-branches 
unappendaged, smooth or with a pubescent ring belozv. —Cynareae (Thistle 
Tribe). 
* 
Achenes inserted on the receptacle by their very base. 
Filaments distinct; pappus of plumose bristles, united at base and deciduous, 
in a ring. 
Bristles of the pappus in a single series; achenes not angled. 
31. Cirsium. 
Bristles of the pappus in several series; achenes somewhat 4 angled. 
32. Cynara. 
Filaments united below ; pappus of narrow barbellate paleae.33. Silybum. 
Achenes obliquely or somewhat laterally inserted on the receptacle ; pappus-bristles 
or scales in 2 or 3 rows or none.34. Centaurea. 
B. Plants with milky juice; both disk and ray-flowers with ligulate 
corollas.—C ichorieae (Chicory Tribe). 
Pappus of bristles, the bristles (or some of them) plumose. 
Receptacle with chaff-like bracts ; at least the inner achenes beaked; flowers 
yellow ; stems naked ; leaves basal.35. Hypochaeris. 
Receptacle naked. 
Bracts of involucre in 2 unlike series. 
At least the inner achenes with a slender beak, all the achenes 
ribbed; flowers yellow ; low branching thistle-like biennial.... 
36. Picris. 
Achenes not beaked nor ribbed ; flowers pink; tall annuals, panicu- 
lately branching above.37. Stephanomeria. 
Bracts of the involucre in 1 series, united at the base; at least the inner 
achenes with a slender beak, all the achenes ribbed; flowers 
purple ; perennial or biennial with grass-like leaves. 
38. Tragopogon. 
Pappus of fine soft capillary bristles, scabrous but never plumose. 
Achenes not beaked ; receptacle naked or bristly. 
Achenes not flattened; stems commonly branching or the plants with 
the leaves all basal..39. Malacothrix. 
Achenes flattened; leafy-stemmed plants.40. Sonchus. 
Achenes beaked; receptacle naked. 
Achenes flattened; leafy-stemmed plants; heads in a panicle. 
41. Lactuca. 
Achenes not flattened ; leaves all basal; heads solitary.42. Agoseris. 
1. GRINDELIA Willd. Gum Plant 
Coarse perennial herbs, sometimes woody at base. Heads usually gum¬ 
my. Involucre campanulate or hemispherical, the bracts many-ranked, 
often with attenuate squarrose points. Pappus of 2 to 8 deciduous awns 
or scales. Involucral cups of budding heads filled with the gummy exuda¬ 
tion. (H. Grindel, Russian botanist.) 
Involucre hemispherical, with conspicuous foliaceous bracts.1. G. robusta. 
Involucre urnshaped-campanulate, without foliaceous bracts.2. G. camporum. 
1. G. robusta Nutt. var. maritima Jepson. Gum Plant. Stems erect, 
2.8 to 5.7 dm. high; leaves oblong to ovate or lanceolate, serrate or the 
upper entire; heads few in a terminal cyme; bracts foliaceous; mature 
