644 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Rays present. 
Involucral bracts spatulate or linear-oblanceolate; rays 
deeply cleft, purple; heads turbinate. 
100. OTHAKE (p. 722). 
Involucral bracts obovate or broadly oblong; rays not deeply 
cleft, not purple; heads campanulate. 
Rays inconspicuous, scarcely exceeding the disk; heads 
small; plantsglabrous...101. HyMENoTHRrix (p. 722). 
Rays large, white; heads large; plants tomentose. 
Pappus of numerous prominent palez. 
’ . 99. HyMENOPAPPUS (p. 720). 
Pappus an obscure crown ...102, Leucampyx (p. 723). 
Bracts neither colored nor scarious. 
Flowers pink...........2......---..-- 103. CHAENACTIS (p. 723). 
Flowers never pink, mostly yellow. 
Achenes 4-angled. 
Leaves alternate. 
Leaves entire; pappus of 10 palee. 
107. PLATYSCHKUHRIA (p. 725). 
Leaves dissected; pappus wanting or of 12 or more scales, 
108. VILLANOVA (p. 725). 
Leaves, at least the lower, opposite. 
Foliage not impressed-punctate; receptacle conic; leaves 
entire... 2.2... eee ee ee eee eee eee 104. Barrta (p. 723). 
Foliage impressed-punctate; receptacle flat or convex; 
leaves dissected. 
Annuals; leaf segments filiform or nearly so. 
106. AcHYROPAPPUS (p. 724). 
Perennials; leaf segments oblong to linear. 
Leaf blades impressed-punctate; involucral — bracts 
carinate............ 105. PicRADENIOPsIS (p. 724). 
Leaf blades not impressed-punctate; bracts not cari- 
nate ......2--- eee eee eee eee 105a. Banta (p. 724). 
Achenes 5 to 10-ribbed. 
Bracts of the involucre spreading or reflexed. 
Leaves decurrent; tubes of disk corollas very short or reduced 
to aring...............--.--.--109. HELENIUM (p. 726). 
Leaves not decurrent; tube of the disk corollas long. 
110. DuGaLpEa (p. 726). 
Bracts of the involucre erect, never spreading nor reflexed. 
Pappus wanting; involucres few-flowered. 
111. FLAvERIA (p. 726). 
Pappus present; involugres many-flowered. 
Bracts of the involucre unequal, the outer united at the 
base. 
Leaves opposite; plant glabrous. 
112. SarTWELLIA (p. 727). 
Leaves alternate or basal; plants more or less pubescent. 
Stems monocephalous; plants woody throughout. 
113. Macpouaatia (p. 727). 
Stems branched and bearing numerous heads; 
plants sparingly if at all woolly. 
114. HyMENOXYS (p. 727). 
