3-S 



i [I HORIACEAE. 



Vol. III. 



8. Crepis occidentalis Nutt. Large-flowered 



dray flawksbcanl. J r ig. 4093. 



Crepis occidentalis Nutt. Jonrn. Acad. Phila. 7: 29. 1834. 



Perennial, scurfy and caneseent, sometimes also hir- 

 sute; stem rather stout, leafy, branched, 6-18' high. 

 Leaves oblong-lanceolate or oblong in outline, laciniate- 

 pinnatifid, acute or acuminate, the lower and basal ones 

 6'-io' long, narrowed into petioles, the upper sessile and 

 slightly clasping; heads few or several, corymbose, 

 stout-peduncled, about 1' broad, 10-30-flovvered ; invo- 

 lucre oblong-campanulate, caneseent, its principal bracts 

 9-24, linear, acute; achenes oblong, sharply 10-ribbed, 

 glabrous. 



Plains, western Nebraska (according to Gray) ; Colorado 

 to California, north to Montana and British Columbia. 

 May-July. 



22. HIERACIUM [Tourn.] L. Sp. PI. 799. 1753. 



Perennial hispid scabrous glandular or glabrous herbs, with alternate or basal leaves, 

 and small middle-sized or large, solitary corymbose or paniculate heads of yellow orange or 

 red flowers. Involucre cylindric, campanulate, or nearly hemispheric, its principal bracts in 

 1-3 series, the outer either regularly and gradually smaller or abruptly much smaller, none 

 of them much thickened at the base after flowering. Receptacle flat, naked or short-fimbril- 

 late. Rays truncate and 5-toothed at the apex. Anthers sagittate at the base. Style-branches 

 slender. Achenes oblong, columnar, or fusiform, not beaked, 10-15-ribbed, terete or 4-5- 

 angled. Pappus copious, or 1-2 rows of simple rather stiff persistent brown or brownish 

 bristles. [Greek, hawk.] 



Not fewer than 300 species, natives of the north temperate zone and the Andes of South Amer- 

 ica. Besides the following, some 20 others occur in western North America. Known as Hawkweed, 

 Hawk-bit, or Speerhawk. Type species: Hieracium murdrum L. 



A. Rootstock short, erect; plants without stolons. 

 a. Heads l'2' broad. 



Stem with 1-5 leaves only ; basal leaves tufted ; introduced species. 



Leaves cordate or subcordate; scape naked or i-leaved. 



Leaves narrowed at the base ; stem several-leaved. 

 Stem very leafy up to the inflorescence ; native species. 



Leaves short, ovate to ovate-lanceolate, rounded or clasping at the base. 



Leaves elongated, linear-lanceolate, narrowed at the base. 



1. H. murorum. 



2. H. vulgatum. 



3. H. canadense. 



4. H. scabriusculum. 



b. Heads less than 1' broad. 



* Stem leaf-bearing nearly or quite up to the inflorescence, the upper leaves sometimes very small 

 and distant. 

 Pubescence of abundant brownish or whitish hairs Vz'-i' long; inflorescence elongated. 



5. H. longipilum. 

 Pubescence of short hairs, or nearly or quite wanting. 



Leaves lanceolate to oblong-lanceolate, acute or acuminate, glabrous. 6. H. paniculatum. 

 Leaves elliptic to obovate, mostly obtuse. 



Stem hispid-pubescent, densely glandular-hispid above ; the peduncles stout, spreading. 



7. H. scabrum. 

 Stem loosely pubescent; pedicels slender. 



Inflorescence elongated ; achenes spindle-shaped. S. H. Gronoz'ii. 



Inflorescence corymbiform ; achenes columnar, truncate. 9. H. marianum. 



** Leaves all basal or 1 or 2 borne on the stem above. 



Basal leaves elliptic to obovate or oblong-spatulate ; native species. 



Pedicels and involucres glabrous or nearly so ; ieaves glabrous or loosely pubescent. 



10. H. venosum. 

 Pedicels and involucres glandular-pubescent; leaves villous. 11. H.Greenii. 



Basal leaves narrowly oblanceolate, introduced. 12. H. florentinum. 



B. Rootstock elongated, slender; plants mostly stoloniferous, scapose. 



Scape bearing a single head, rarely 2 to 4. 

 Heads several or many, corymbose. 

 Flowers yellow. 



Plant glaucous ; leaves glabrous or nearly so above. 

 Plant not glaucous; leaves hirsute on both sides. 

 Flowers orange. 



13. H.Pilosella. 



14. H. floribundum. 



15. H. pratense. 



16. H. anrantiaenm. 



