THISTLE FAMILY 873 



30. TOWNSENDIA Hook. 



Tufted scapose or caulescent plants, often with caudex-like stems or branches. 

 Leaves alternate, entire, often crowded, usually broadest above the middle. 

 Heads rather large, sessile or peduncled. Involucres hemispheric; bracts imbri- 

 cate, in several series, herbaceous, with more or less scarious margins; receptacle 

 broad, flat, alveolate. Ray-flowers pistillate; ligules white, rose, or purplish. 

 Disk-flowers mostly perfect. Anthers obtuse and entire at the base. Style- 

 branches flattened, with lanceolate appendages. Achenes various, those of the 

 rays usually 3-angled and those of the disk flattened. Pappus of a single series 

 of scales or awns, or that of the ray-flowers sometimes reduced to a crown of 

 small scales. 



Bracts acuminate. 



Caulescent biennials or short-lived perennials. 



Stems spreading, with branches from the base, which surpass them in length. 



1. T. grandiflora. 

 Stems erect or nearly so, simple or with short branches above. 



Stems over 3 dm. high, generally branched; basal leaves oblanceolate. 

 Involucre 1.5-2 cm. broad, naked. 2. T. eximia. 



Involucre 2-3 cm. broad, generally subtended by leaves. 3. T. Vreelandii. 

 Stems 1-2 dm. high, generally simple and monocephalous, sometimes several 



from one root; basal leaves spatulate. 4. T. Parry i. 



Acaulescent perennials, depressed, monocephalous. 



Plant pilose or hirsute. 5. T. alpina. 



Plant arachnoid-lanuginose. 6. T. condensata. 



Bracts acute or obtuse. 



Plant with evident leafy stems. 



Stems 5-20 cm. high; mostly annuals and biennials. 

 Pappus of disk- and ray-flowers elongate bristles. 



Leaves linear or oblanceolate; pappus of the rays nearly as long as that of 



the disk-flowers. 7. T. florifer. 



Leaves spatulate; pappus of the ray-flowers much shorter than that of the 



disk-flowers. 8. T. ambigua. 



Pappus of the rays reduced to a crown of short squamellae. 



Bracts of the involucre in 3 series; pubescence of the stem appressed; 



leaves linear. 9. T. Fendleri. 



Bracts in 2 series; pubescence of the stem not strictly appressed; earlier 



leaves spatulate. 10. T. $trigosa. 



Stem usually evident, but short. 1-5 cm. long; mostly cespitose perennials. 

 Leaves more or less cinereous. 



Outer bracts rounded-obtuse at the apex; achenes almost glabrous. 



11. T. montana. 

 Outer bracts acute; achenes pubescent. 



Heads distinctly peduncled; hairs of the achenes not glochidiate-capi- 



tellate. 12. T. scapigera. 



Heads subsessile; hairs of the achenes glochidiate-capitellate. 

 Stem-leaves oblanceolate or linear. 



Pappus of the rays of bristles one-third to one-half as long as 

 those of the disk-flowers; ray-flowers glandular-puberulent 

 outside. 13. T. incana. 



Pappus of the rays reduced to a crown of short squamellae; ray- 

 flowers glabrous. 10. T. strigosa. 

 Leaves all decidedly spatulate; pappus-bristles of ray- and disk- 

 flowers all alike. 14. T. arizonica. 

 Leaves glabrous or nearly so. 15. T. glabrella. 

 Plant acaulescent; heads sessile among the rosulate leaves. 

 Plant not lanate. 



Plant glabrate, cinereous only when young; leaves oblanceolate or spatulate. 

 Bracts obtuse; ray-flowers with very short pappus. 16. T. Rothrockii. 

 Bracts acute; pappus of disk- and ray-flowers alike, of long bristles. 



Leaves glabrous above. 17. T. Wilcoxiana. 



Leaves strigose on both sides. 



Head 12-15 mm. high; pappus twice as long as the achenes; bracts 

 lanceolate. 18. T. intermedia. 



Head less than 1 cm. high; pappus a little longer than the achenes; 



bracts linear. 19. T. leptotes. 



Plant permanently cinereous; leaves linear or linear-oblanceolate. 



20. T. exscapa. 

 Plant lanate. 21. T. spathulata. 



1. T. grandiflora Nutt. Biennial, with a taproot; stem 2-10 cm. high, 

 densely strigose; leaves narrowly linear-oblanceolate, strigose; involucre 10-15 

 mm. high, 15-20 mm. broad; bracts strigose, broadly lanceolate, acuminate, fim- 

 briate; ligules rose-purple or pinkish, 15-20 mm. long; pappus of the ray-flowers 

 reduced to a crown of short squamellae. Plains and hills: S.D. Okla. Colo. 

 Wyo. Plain Subalp. Je-Au. 



