254 CARDUACEAE 



Stem 1-3 dm. liigh: segments of the leaves 1-3 cm. Ions, ovate, entire or 



slightly toothed. 5. B. incana. 



Stem 3 dm. or more liigh; segments of the leaves 3-5 cm. long, lanceolate, 

 coarsely toothed. fi. B. floccosa. 



Plant finely canescent, tomentose only on the involucre; some of the leaves merely 

 toothed. 7. B. terebinthacea. 



Plants more or less hispid, neither canescent nor tomentose. 



Disk 3-4 cm. broad: segments of the leaves mostly entire. S. B. macrophylla. 



Disiv 2-2.5 cm. broad; segments of the leaves mostly toothed. 9. B. hirsuta. 



72. WYETHIA Nutt. Mule-e.\r.s. 



Involucral bracts nearly equal, in 2-3 series; stem not wliite. 



Rays pale yellow or wliite; plant hispid. 1. W. helianthoidcs. 



Ravs bright vellow. 



Plant glabrous. 2. W. ample licaulis. , 



Plant pubescent. 



Plant sparingly liirsute or scabrous. 3. W. robusta. 



Plant densely pubescent. 4. W. arizonica 



Involucral bracts unequal, the outer much shorter, in 5-6 series; stem white. 



5. W. scabra. 



73. HELIANTHUS L. Sun-flower, Ground Artichoke. 



Annuals: leaves broad, ovate or cordate or lanceolate; disk purple or dark brown. 

 Bracts ciliate, liispid, ovate or obovate, abruptly acuminate. 



Lower leaves at least ovate or cordate, distinctly toothed. 1. H. lenticularis. 

 Leaves lanceolate or narrowly deltoid, minutely toothed or entire. 



2. H. aridus. 

 Bracts not ciliate, canescent-strigose, lanceolate. 3. //. petiolaris. 



Perennials. 



Disk dark brown or purple. 



Leaves hnear. 4. II. orgyalis. 



Leaves rhombic-ovate. 5. H. subrhomboideus. 



Di.sk yellow or light brownish. 



Bracts broadly lanceolate, acute, appressed. 6. H. pumilus. 



Bracts narrowly lanceolate, acuminate, more or less spreading or squarrose. 

 Leaves ovate. 7. H. luberosus. 



Leaves lanceolate. 



Leaves rounded or obtuse at the base, subsessile. 8. H. divaricatus. 

 Leaves tapering at the base, petioled. 



Stem more or less scabrous or hispid; upper leaves subsessile. 



Leaves and stem very scabrous. 9. H. Maximiliani. 



Leaves scabrous above, hirsute beneath: stem more or less hirsute. 

 Upper leaves mostly alternate and indistinctly triple-nerved. 



10. II. giganteus. 

 Leaves usually all opposite, distinctly triple-nerved. 



Leaves lanceolate, thick, often toothed, yellowish green, the 



lower distinctly petioled. 11. H. subtuberosus. 



Leaves Unear-lanceolate, dark green, entire, all sulisessile. 



12. H. Cusickii. 

 Stem, except the upper portion, glabrous and glaucous; leaves mostly 



all petioled. 

 Lower leaves coarsely toothed; bracts hirsute ciliate. 



13. H. grosse-serratus. 

 All leaves distantly and minutely denticulate or subentire; bracts 



not ciUate or ciUate merely at the base. 

 Leaves lanceolate, often somewhat triple-ribbed. 



Leaves all opposite; bracts ciliate on the margins. 



11. H. subtubprosus. 

 Leaves mostly alternate; bracts ciliate only below the middle. 



14. H. fasciculoris. 

 Leaves narrowly lineai -lanceolate, not triple-ribbed. 



15. H. NuUallii. 



74. ENCELIA Adans. 



Leaves densely white-tomentose. 1- E- farinosa. 



Leaves hispidiilous-canescent. -■ E- rirgincnsis. 



75. ENCELIOPSIS (A. Gray) A. Nels. 



Plant white-tomentose; heads radiate. 



Stem scapiform; leaf-blades orbicular or spatulate; ligules 1-2.5 cm. long. 



1. E. nudicaulis. 



Stem leafy; leaf-blades rhomblc-obovate; ligules 3.5-4 cm. long. 2. E. argophiilUi. 

 Plant hispid-scabrous: heads discoid. 3. E. nutans. 



76. HELIANTHELLA T. & G. 



Paleae of the receptacle soft and scariotis. 



Disk 2-3 cm. in diameter; leaves ovate to lanceolate, thin, not strongly reticulate. 



1. //. quinquenervis. 

 Disk less than 2 cm. wide; leaves oblanceolate to linear, strongly reticulate. 



