CARDUACEAE. 
333 
Receptacle from flat to convex. 
Achenes of the disk neither sharp-angled, margined nor winged. 
Rays fertile; their achenes commonly 3-angled or obcompressed; 
plants with thick balsamiferous tap-roots. 
Pappus none; stem scapiform or with reduced leaves. 
48. Balsamorrhiza. 
Pappus a lacerate chaffy crown or of distinct chaffs; stem 
low but leafy. 49. Wyethia. 
Rays sterile or wanting; plants not with fleshy tap-root. 
Pappus none or a minute ring. 45. Gymnolomia. 
Pappus of 2 scarious awns. 50. Helianthus. 
Achenes of the disk thin-edged, margined or winged. 
Ray-flowers neutral; achenes scarcely winged. 
51. Helianthella. 
Ray-flowers fertile; achenes winged. 52. Ximenesia. 
b. Achenes obcompressed; chaffs flat or hardly concave; involucres 
distinctly double. 
Bracts of the involucres distinct or nearly so. 
Pappus in ours of small teeth, a mere border, or wanting. 
53. Coreopsis. 
Pappus of 2-4 barbed or hispid awns. 54. Bidens. 
Bracts of the inner involucre united at least to near the middle. 
55. Thelesperma. 
2. Pappus of 5-many, linear to lanceolate scales with thickened axis and 
hyaline margins. 74. Gaillardia. 
B. Bracts of the involucres uniserial, partly or wholly enclosing the achenes of 
the fertile ray-flowers; plants glandular-viscid. 56. Madia. 
Tribe 6. HELENIAE. 
A. Plant-tissues without oil-glands. 
I. Ligules persistent and becoming papery on the striate achenes ; plants more 
or less woolly. 57. Psilostrophe. 
II. Ligules deciduous or none. 
a. Achenes flat with only marginal nerves; disk-corollas 4-toothed. 
58. Pericome. 
b. Achenes angled, not flat, nerved or striate. 
1. Receptacle naked. 
a. Bracts of the involucres pale or colored, at least the margins and 
tips scarious. 
Corollas of the disk-flowers with reflexed or spreading lobes; bracts of 
the broadly campanulate involucres obovate or broadly oblong. 
Heads discoid. 59- Hymenopappus. 
Heads radiate ; ligules obscurely toothed, yellowish or white. 
60. Leucampyx. 
Corolla of the disk-flowers with linear, erect lobes; bracts of the 
turbinate involucres spatulate to linear-oblanceolate in two series; 
heads in our species radiate; ligules deeply cleft, purple. 
61. Polypteris. 
b. Bracts of the involucres neither colored nor scarious. 
Achenes 4-angled. 
Foliage impressed punctate; leaves, at least the lower, opposite. 
Perennials, suffruticose at the base; leaf-segments oblong to 
linear. 62. Picradeniopsis. 
Annuals; leaf-segments filiform or nearly so. 
63. Achyropappus. 
Foliage not impressed-punctate ; leaves alternate. 
Bracts obovate, cuneate or oblanceolate. 
Perennials with a woody caudex; leaves entire; pappus of 10 
scales. 64. Platyschkuhria. 
Annuals; leaves dissected ; pappus in our species wanting. 
65. Bahia. 
66. Chaenactis. 
Bracts linear. 
