THISTLE FAMILY 915 



Leaves tomentose on both sides. VI. Apricae. 



Leaves glabrous above. VII. C.\MPESTRE3. 



Plant acaulescent; heads subscssile among the rosettes of the basal leaves. 



VIII. ROSULu\TAE. 



Plants not surculose-proliferous ; stolons erect. 



Heads 4-5 mm. high; bracts nearly glabrous, scarious throughout; leaves silky- 



tomcntose. IX. Arge\te.\e. 



Heads 0-10 mm. high; bracts tomentose at the base, only tips scarious; leaves 

 villous-tomentose. X. Pulc'HERRI!VL\e. 



Pappus-bristles of the small stamlnate heads not clavate; achenes puberulent; hairs 

 bifurcate at the ape.x; plant low and densely cespitose. XI. Dimorphae. 



I. Racemosae. 

 Leaves of the rosettes oval or spatulate; lower pedicels 2-5 cm. long. 



1. A. racemosa. 

 Leaves of the rosettes oblanceolate ; lower pedicels 1 cm. long or less. 



2. A. oblancifolia. 

 II. Alpinae. 



Leaves glabrous above. 



Leaves of the rosettes narrowly oblanceolate; heads usually several; bracts of the 



pistillate heads abruptly acuminate. 3. A. alpina. 



Leaves of the rosettes broadly oblanceolate or spatulate; inner bracts acute or acum- 

 inate, the outer obtuse. 

 Heads usually sohtary. 4. A. monocephala. 



Heads 3-6 in a cluster. 5. A. chlorantha. 



Leaves tomentose on both sides; bracts acute or obtuse. 



Leaves of the rosettes broadly obovate-ciuieate, subsessile. 



Heads 7-8 mm. liigh; leaves 8-10 mm. long; tips of bracts dark brown. 



6. A. puh'ina'.a. 

 Heads 5-6 mm. high; leaves less than 8 mm. long; tips of the bracts light brown. 



7. A. albescens. 

 Leaves of the rosettes spatulate or oblanceolate, distinctly petioled. 



Heads 6-8 mm. high. 8. A. fusca. 



Heads 5-6 mm. high. 



Bracts very dark, almost black at the base, but often with white tips. 

 Inner bracts of the pistillate heads acute. 



Leaves narrowly oblanceolate, acute or short-aciuninate ; tomentum 



very fine and appressed. 9. A. acuta. 



Leaves spatulate or broadly oblanceolate, obtuse; tomentum rather 

 loose. 10. A. media. 



Bracts obtuse or rounded. 11. A. mucronata. 



Bracts moderately dark, umber-colored to hght brown. 

 Inner bracts not rose-colored. 



Leaves appressed-tomentose, sliining and yellowish. 



Bracts of the pistillate heads linear-lanceolate, acute. 



12. A. Sansoni. 

 Bracts of the heads oblong, obtuse. 



Heads sessile; stolons decumbent. 13. A. flavescens. 



Heads pedimcled; stolons ascending. 14. A. confinis. 



Leaves white-tomentose, very rarely yellowish. 

 Heads 2 or 3; leaves broadly obovate-spatulate. 



15. A. aizoides. 

 Heads several; leaves spatulate or oblanceolate. 



Bracts of the pistillate heads obtuse. 



Involucres more or less viscid ; bracts with whitish tips. 



23. A. sedoides. 

 Involucres not viscid, bracts umber-colored. 



16. A. umhrinella. 

 Bracts of the pistillate heads acute. 17. A. Macounii. 



Inner bracts rose-colored. 18. A. concinna. 



III. ROSEAE. 



Leaves cuneate-spatulate, obtuse, without distinction between blade and petiole. 



18. A. concinna. 

 Leaves oblanceolate or si)atulate, with distinct petioles. 



Leave-s narrowly oblanreolate, acute. 19. A. rosea. 



Leaves broadlyspatulato, obtuse. 20. A. imbricata. 



IV. N.\KDINAE. 



One species. 21. A. corymbosa. 



V. Aridae. 

 Stem-leaves 6-8 mm. wide, oblong or the uppermost lanceolate. 22. A. foliacea. 

 Stem-leaves 2-5 mm. wide, Unear or oblanceolate. 



Bracts with a large brown or green spot, more or less viscid. 23. A. sedoides. 

 Bracts sUghtly if at all spotted, not viscid. 

 • Bracts of the pistillate heads obtuse; plant 1-2 dm. high. 



Bracts of the pistillate heads with oblong to linear upper portions. 



24. A. arida. 

 Bracts of the pistillate heads with oval or obovate upper portions. 



25. A. scariosa. 



