838 CARDUACEAE 



Ray-flowers fertile; achenes winged; pappus-awns without inter- 

 mediate squamellae. 77. XIMENESIA. 



6. Achenes obcompressed ; paleae flat or hardly concave; involucres dis- 

 tinctly double. 

 Bracts of the involucres distinct or nearly so. 



Pappus in ours of small teeth, a mere border, or wanting. 



78. COREOPSIS. 



Pappus of 2-4 barbed or hispid awns. 79. BIDENS. 



Bracts of the inner involucre united at l^ast to near the middle. 



80. THELESPERMA. 

 2. Pappus of 5-many, linear to lanceolate squamellae with thickened axis and 



hyaline margins. 

 Rays fertile; paleae of the receptacle thin and scarious; pappus-squamellae 



flmbriate. 81. PTILONELLA. 



Rays sterile; paleae of the receptacle bristle-form; pappus-squamellae not 



flmbriate. 110. GAILLARDIA. 



B. Bracts of the involucres uniserial, partly or wholly enclosing the achenes of the fer- 

 tile ray-flowers; plants glandular- viscid. 

 Achenes of the inconspicuous rays laterally compressed and enclosed in the con- 



duplicately infolded involucral bracts. . 



Disk-flowers several; corolla hairy; stout annuals with sessile or short-peduncled 



heads. 82. MADIA. 



Disk-flowers solitary; corolla glabrous; slender low annuals with small heads on 



filiform peduncles. 83. HARPAECARPUS. 



Achenes of the ray-flowers with broad and rounded backs, or more commonly obcom- 

 pressed. 



Ligules of the ray-flowers minute; achenes completely invested by the whole 

 involucral bract; disk-flowers solitary; heads small and short-peduncled. 



84. HEMIZONELLA. 



Ligules of the ray-flowers conspicuous; achenes enclosed in the basal portion of 

 the bracts, the dilated margins of which are abruptly infolded; disk-flowers 

 several or many. 

 Ray-flowers about 5, with deeply 3-cleft ligules; disk-flowers sterile, without 



pappus. 85. LAGOPHYLLA. 



Ray-flowers 8-20, with merely 3-lobed or toothed ligules; disk-flowers mostly 

 fertile with pappus of 5-20 bristles. 86. BLEPHARIPAPPUS. 



Tribe 7. HELENIAE. 



I. Ligules persistent and becoming papery on the striate achenes; plants more or less 



woolly. 

 Pappus of scales; rays 34, very broad; involucres of 410 coriaceous woolly bracts. 



87. PSILOSTROPHE. 



Pappus none; rays 5-50; involucres of numerous thin herbaceous bracts, 



88. BAILEYA. 



II. Ligules deciduous or none. 



A. Achenes flat with only marginal nerves; disk-corollas 4-toothed. 

 Pappus none or of a single bristle; bracts distinct; suffruticose plants. 



89. MONOTHRIX. 

 Pappus of a lacerate-ciliate crown and sometimes with an additional pair of short 



awns; bracts more or less connate; not suffruticose plants. 



90. 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 scari- 

 ous. 

 Corollas of the disk-flowers with reflexed or spreading lobes ; bracts of the 



broadly campanulate involucres obovate or broadly oblong. 

 Heads discoid. 96. HYMENOPAPPUS. 



Heads radiate; ligules obscurely toothed, yellowish or white. 



97. LEUCAMPYX. 



Corolla of the disk-flowers with linear, erect lobes; bracts of the turbinate 

 involucres spatulate to linear-oblanceolate in two series; ligules if pres- 

 ent deeply cleft, purple. 98. OTHAKE. 

 o. Bracts of the involucres neither colored nor scarious. 



Pappus of numerous barbellulate white bristles, somewhat broadened and 

 united at the base into a ring. 104. SYNTRICHOPAPPUS. 



Pappus of scales or wanting. 



Achenes either linear-prismatic or clavate-obpyramidal, i. e., very 



elongate. 

 Bracts more or less carinate-concave and partly enfolding the 



achenes; leaves more or less floccose woolly. 

 Low and diffuse winter annuals; anther-tips subulate; bracts 

 herbaceous; tube of the disk-corollas equalling the throat. 



103. ANTHEROPEAS. 



Perennials; anther-tips obtuse; bracts firm; tube of the disk- 

 corollas shorter than the throat. 102. ERIOPHYLLUM. 

 Bracts wholly herbaceous, broad and flat or merely concave, not 



embracing the achenes; plants not floccose-lanate. 

 foliage impressed-punctate; leaves at least the lower opposite. 

 Perennials, suffruticose at the base; leaf-segments oblong to 

 linear. 91. PICRADENIOPSIS. 



