1270 CARDUACEAE 



41. Helianthua tracheliifolius Willd. Perennial, deep green. Stems 7-20 dm. tall, 

 pubescent, but commonly only roughened by the remains of the hair-bases in age : leaves 

 mainly opposite ; blades lanceolate to oblong-lanceolate, 8-18 cm. long, acuminate, sharply 

 serrate, or with the teeth obscured by the revolute margins, scabrous above, more or less 

 pubescent beneath, narrowed into petiole-like bases : heads showy : involucral bracts linear- 

 lanceolate to lanceolate, with slenderly elongated lax tips, pubescent and finely ciliate : 

 ray-flowers 9-19 ; ligules yellow, 3-4 cm. long : disk about 1.5 cm. wide. 



In dry soil, Pennsylvania to Wisconsin, North Carolina and Arkansas. 



42. Helianthus hirsiitus Raf. Perennial, hirsute or hispid. Stems 5-12 dm. tall, 

 sometimes branching : leaves opposite ; blades usually firm, lanceolate, 5-15 cm. long, 

 acuminate, serrate or nearly entire : heads showy : involucral bracts linear-lanceolate, lan- 

 ceolate or oblong-lanceolate, each attenuate into long spreading tips, hispidulous : ray- 

 flowers 12-15 ; ligules 2.5-3.5 cm. long : disk 1.5-2 cm. broad. 



In dry soil, Pennsylvania to Wisconsin, Georgia and Texas. 



43. Helianthus divaricatus L. Perennial, deep green. Stems 3-12 dm. tall, simple 

 or with slender branches above, commonly smooth, and glabrous, sometimes glaucescent : 

 leaves opposite, spreading ; blades lanceolate or ovate-lanceolate, acuminate, entire or 

 sharply and coarsely serrate, sessile or nearly so : heads rather showy : involucral bracts 

 lanceolate or oblong-lanceolate, 8-10 mm. long, acuminate, ciliate : ray-flowers 7-15 ; lig- 

 ules 2-2.5 cm. long: disk 1-1.5 cm. broad. 



In dry, open woods, Ontario to the Northwest Territory to Florida and Louisiana. Summer. 



44. Helianthus mdllis Lam. Perennial, canescent. Stems 6-10 dm. tali, often 

 branched above : leaves opposite ; blades ovate to ovate-lanceolate, 5-15 cm. long, acute 

 or acuminate, nearly entire or serrate, sessile or clasping : heads showy : involucral bracts 

 oblong-lanceolate to lanceolate, or cuneate with a lanceolate tip, 1-1.5 cm. long, acuminate, 

 bristly, the outer ones spreading: ray -flowers 13-26 ; ligules yellow, 2-3 cm. long: disk 

 2-3 cm. broad. 



In dry often barren grounds, New York to Iowa, Georgia and Texas. Summer. 



97. ENCELIA Adans. 



Annual or perennial herbs or shrubby plants, with usually pubescent or glandular foli- 

 age. Leaves alternate or opposite : blades mainly of an ovate type. Heads radiate or rarely 

 discoid, often showy, peduncled. Involucres hemispheric or flattish : bracts mainly lanceo- 

 late or linear-lanceolate. Receptacle somewhat convex, chatty. Ray-flowers several, neu- 

 tral : ligules yellow. Disk -flowers perfect, fruit-producing : corollas yellow or brown. 

 Anthers slightly sagittate at the base. Stigmas with elongated pubescent appendages. 

 Achenes flattened. Pajipus wanting, or a small awn at each margin of the achene. The 

 plants flower from spring to fall. 



Achenes pilose, ciliate above : pappus of 2 short awns. 1. E. subaristata. 



Achenes glabrous : pappus wanting. 2. E. calva. 



1. Encelia subaristata A. Gray. Foliage hispidulous and somewhat canescent. 

 Stems 3-11 dm. tall, branching: leaves opposite; blades ovate to hastate, 3-7 cm. long, 

 crenate-serrate, subcordate at the base: peduncles elongated : heads solitary, rather showy : 

 involucral bracts linear-lanceolate to lanceolate : ray-flowers 13-19 ; ligules yellow, 8-10 

 mm. long : achenes 5-6 mm. long, pilose, ciliate near the top, with 2 rigid hispidulous 

 awns 5 as long as the achene or shorter. 



On plains and prairies, Texas and adjacent Mexico. 



2. Encelia cdlva (Engelm. & Gray) A. Gray. Foliage scabrous to hispidulous. 

 Stems 3-9 dm. tall, branching : leaves opposite ; blades deltoid-ovate to hastate, 2-7 cm. 

 long, serrate, broadly cuneate or subcordate at the base : peduncles elongated : heads soli- 

 tary, showy : involucral bracts linear-lanceolate to almost linear, the outer with spreading 

 tips, densely hispidulous : ray-flowers 11-17 ; ligules 10-12 mm. long : achenes 5-6 mm. 

 long, glabrous, without pappus. 



On stony hills, Texas and adjacent Mexico. 



98. HELIANTHELLA T. & G. 



Perennial caulescent herbs with tuber-bearing roots. Leaves alternate or opposite : 

 blades entire or sparingly toothed. Heads radiate, heterogamous, showy, peduncled. In- 

 volucres often hemispheric : bracts imbricated in 2 or 3 series, the outer often longer than 

 the inner. Ray-flowers neutral : ligules yellow. Disk-flowers perfect, fruit-producing : 



