THISTLE FAMILY 933 



Ray-flowers neutral, yellow, or none. Disk-flowers hermaphrodite, fertile; 

 corollas yellow or brown. Anthers slightly sagittate at the base. Style-branches 

 with elongated pubescent appendages. Achenes flattened, wingless. Pappus 

 wanting (in ours) or a small awn at each angle of the achenes. 



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



Leaves hispidulous-canescent. 2. E. virgincnsis. 



1. E. farinosa A. Gray. Shrub, 5-15 dm. high; leaves petioled; blades ovate, 

 obtuse, 2-5 cm. long, triple-nerved, entire; heads nodding; involucres about 8 

 mm. high, 1-1.5 cm. wide; bracts lanceolate or linear-lanceolate, sparingly pilose 

 or nearly glabrous, the outer reflexed; ligules 6-10, yellow, 8-12 mm. long; 

 achenes obovoid, with a deep notch. Dry hills: Ariz. s Utah s Calif.; Mex. 

 L. Son, N-My. 



2. E. virginensis A. Nels. Shrub 3-10 dm. high; leaves alternate, short- 

 petioled; blades broadly rhombic- or deltoid-ovate, triple-nerved at the base, 

 1-3 cm. long, hispidulous as well as canescent-puberulent; involucres 8 mm. high, 

 10-15 mm. broad; bracts hirsute-canescent, lanceolate, acute or acuminate; 

 ligules 12-20, deeply 2- or 4-toothed, 15-20 mm. long; achenes linear-cuneate, 

 slightly depressed at the apex, ciliate on the margins. Dry hills: s Utah s Calif . 

 L. Son. Ap-My. 



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



Silvery or canescent, often acaulescent scapose perennials. Heads radiate 

 or in an anomalous species discoid. Involucres flat; bracts imbricate in 2-3 

 series. Receptacle chaffy. Ray-flowers neutral or lacking. Disk-flowers 

 numerous, hermaphrodite and fertile; corollas yellow. Achenes flat, oblong- 

 cuneate, villous, with narrow callous margins at the summit, bordered between 

 the short subulate teeth by a short fringe of membranous confluent squamellae. 



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 rhombic-obovate ; ligules 3.5-4 cm. long. 2. E. argophylla. 

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



1. E. nudicaulis (A. Gray) A. Nels. Acaulescent perennial, with a thick 

 caudex; leaves all basal, petioled; blades thick, orbicular or rounded, spatulate, 

 1-5 cm. long and as broad, 3-5-ribbed; scape naked, 3-5 dm. high; involucre 

 about 1.5 cm. high and 3 cm. wide; bracts lanceolate, white-tomentose; ligules 

 20 or more, 1-2.5 cm. long; pappus-awns scarcely exceeding the hairs. Helian- 

 thclla nudicaulis A. Gray. E. tuta A. Nels. Dry rocky ridges and alkaline soil: 

 Ida. Utah Nev. Son. My-Je. 



2. E. argophylla (S. Wats.) A. Nels. Perennial, with short leaf y stem ; leaves 

 with winged petioles, 5-10 cm. long; blades rhombic-obovate, thick, 3-5-ribbed; 

 involucres about 1.5 cm. high, 2.5-3 cm. wide; bracts tomentose, ovate-lanceo- 

 late, acuminate; ligules about 2.5 cm. long, 3-4 mm. wide; pappus-awns nearly 

 as long as the corolla-tube. Tithonia argophylla S. Wats. Helianthella argo- 

 phylla A. Gray. Alkaline soil: Nev. s Utah. L. Son. Ap. 



3. E. nutans (Eastw.) A. Nels. Subacaulescent perennial, with an erect 

 woody caudex; leaves basal, petioled, clustered; blades oval or obovate, 3-5- 

 ribbed, 2-4 cm. long, hispid-scabrous; heads deflexed in fruit; involucres about 18 

 mm. high, 2.5-3 cm. broad; bracts lanceolate, densely hispid; pappus none. 

 Encelia nutans East. Verbesina scaposa M. E. Jones. Dry mesas: Colo. Utah. 

 Son. My. 



76. HELIANTHELLA T. & G. 



Caulescent perennials, with taproots. Leaves alternate or opposite, more or 

 less distinctly tfiple-ribbed. Involucres hemispheric or flat; bracts more or less 

 imbricate, often foliaceous; receptacles chaffy. Ray-flowers neutral, showy; 

 ligules yellow. Disk-flowers hermaphrodite and fertile; tube of the corollas half 

 as long as the throat; lobes short, ovate, puberulent. Appendages of the style- 

 branches obtuse, short, spatulate or oblong. Achenes flat, cuneate-obovate, 

 emarginate or obcordate. Pappus of several squamellae between the awns or 

 paleaceous teeth. 



