194 



COMPOSITAE (composite FAMILY) 



bescence softly silky-canescent throughout: leaves spatulate-oblong or oblong 

 and sessile: heads few to many, corymbose; bracts of the villous-canescent 

 involucre narrowly linear-lanceolate: outer pappus minute. — Plains of the 

 upper Platte. 



9. CHRYSOTHAMNUS Nutt. Rabbit Brush. 



GOLDENROD 



Rayless or False 



Shrubby or suffrutescent plants with narrow or terete entire leaves. ' Her- 

 bage white-tomentose or glabrous, often viscidulous X)r resinous. Inflores- 

 cence paniculate, cymose, or rarely racemose. Heads homogamous. In^ 

 volucre narrow; the bracts well imbricated usually in more or leSs distinct 

 vertical ranks, chartaceous or coriaceous, mostly destitute of herbaceous tips. 

 Ray-flowers uniformly wanting; disk-flowers 5-30. Style-branches subulate 

 or filiform, usually long-exserted. Achenes narrow, terete or sHghtly angled, 

 pubescent. Pappus copious, soft, commonly dull white. — 'Bigeloma, ■- 



The entire plant wholly devoid of tomentum. 



Tall (5-10 dm.); branchlets slender-virgate or stouter a,nd fa&- 

 tigiate; leaves scabrous-margined. 

 Growing on the wet banks of alkali creeks (strikingly balophy- 

 tic) . ... . . . , . 



Growing on dry hills, in soil free from alkali . 

 Low (5 dm. or lea's); usually frefely branched. 

 ' Leaves glabrous but sometiihesi scabrous on the vaax&ns, 

 Leiives 3-nerved, often involute and twisted , 



Leaves 1-nerved, flat, ciliate on the margin 

 Leaves puberulent or scabrous, but often very, minutely or 

 btjaringly so. 

 Bracts not acurtiinate, but often subacute. 



^ ; Achenes- pubescent 



Achenes glabrous 



Bracts firm' and sharply acuminate 

 Tonientoae, in some species densely so and in the others at least traces 

 upon stems or leaves. 

 Branchlets permanently white-tomentose. 



Plant widely bushy-branched 



Plant strict with erect brs^nches ...... 



Branchlets either glabrate from the first or shedding more or less 

 of their tomentum. 

 Involueral bracts acuminate or at least sharply acute, arachnoid- 

 ciliate. 



Achenes glabrous 



Achenes pubescent. 



Leaves linear, 1-nerved (in no. 12 sometimes surpassing 

 the flowers). 

 Involueral bracts long-acuminate, somewhat divaricate^. ' 

 the upper usually exceeding the corollai ' ' , 



Flowers yellow; bracts arachnoid-ciliate on the mar- ' 



gins; leaves green, not surpassing the flo:wers , ,11, C, affinis. 

 Flowers pale or dirty yellow; bracts lanate; leaves 

 pale or yellowish-green, the upper often longer 



than the flowers 12. C. Howardii. 



Involueral bracts merely acute, erect, shorter than the 

 corolla, arachnoid-ciliate; leaves canaliculate, 3-£ 



cm. long '^ • • • ,• • ■ ■ 13. C. wyomingensis. 



Leaves broadly Imear, 3-nerved, green, the upper surpass- 

 ing the flowers . , , . . • . . . 14. C. Parryij ■ 

 Involueral bracts not acuminate, lanceolate and acute or nar-, 

 rowly oblong and blunt. 

 Bracts quite glabrous, not glutinous; leaves glabrous at ma- 

 turity; stems slender, erect, 4-6 dm. high . ., . 15. C. oreophilus. 

 Bracts erose-ciliate on the margin, or tomentose, or both, and 

 sometimes glutinous; some tomentum persisting on the 

 leaves. 

 Plant 5-12 dm. high, with branched trunk-like base, the 



season's stems slender-virgate, erect .... 16. C. pulcherrimus. 

 Plant 2-5 dm. high, freely branched from the base. 



Leaves almost filiform and'widely divaricate'' .' . 17. C. plattensis. 

 Leaves linear, mostly erect , . . . . . 18. C.! frigidus. 



1. Chrysothamnus linifolius Greene, Pitt. 3: 24. 1896. Tufted-, woody 

 stems erect, slender and flexible, 6-10 dm. high, fastigiately bca-nchiug above, 



1. C linifolius. 



2. C. glauciis. 



3. C. puznilus. 



4. C Greenei. 



6. 0. lanceolatus. 



6. C. Vaseyi. 



7. C.idepressus. 



8. C; graveolens.' 



9. C. causeosus. 



10. C. Biedovii. 



