132 



NORTH AMERICAN FLORA 



[Volume 34 



Guenlheria Spreng. Syst. 3: 356. 1826. 



Gercostylis Less. Syn. Comp. 239. 1832. 



Agassizia Gray & Engelm.; A. Gray, Proc. Am. Acad. 1: 49. 1847. Not Agassizia Chav. 1830. 



Annual, biennial, or perennial herbs, rarely suffruticose at the base, either scapose or 

 caulescent. Leaves alternate or basal, entire, toothed, or pinnatifid, often in the same species. 

 Heads radiate or discoid, peduncled. Involucre saucer-shaped or rotate in anthesis; bracts 

 in 2-3 series, ovate, oblong or lanceolate, at least the upper half strongly reflexed in fruit. 

 Receptacle convex to subglobose, alveolate, usually more or less fimbrillate, the fimbrillae from 

 soft and short-conic, to elongate-subulate, stiff and spine-like or bristle-like. Ray-flowers 

 usually neutral, rarely pistillate and fertile, often wanting; ligules, if present, broad, cuneate 

 or flabelliform, deeply 3-cleft, yellow, or purple, or both. Disk-flowers hermaphrodite and 

 fertile; corolla-tube very short, glabrous, abruptly enlarged into the throat; throat from deeply 

 campanulate, nearly cylindric, to trumpet-shaped, often puberulent; lobes from triangular or 

 ovate and obtuse to lanceolate and acuminate, or subulate from a broad base, pubescent with 

 glandular often moniliform hairs. Anthers auricled at the base. Style-branches appendaged; 

 appendages from glabrous and short to hispidulous and filiform. Achenes broadly obpyram- 

 idal, about twice as long as broad, wholly or partly covered by long, stiff, ascending hairs. 



Type species, Gaillardia pulchella Foug. 



Style-branches with glabrous appendages; acaulescent winter annuals. 



Hairs of the achenes almost covering the short-awned pappus; rays fertile. 1. G. comosa. 

 Hairs of the achenes only half covering the long-awned pappus; rays sterile. 2. G. suavis. 

 Style-branches with long, hispidulous filiform appendages. 



Fimbrillae of the receptacle reduced to small soft teeth; lobes of the disk- 

 corollas caudate-acuminate from a broad base. 

 Disk yellow. 



Stem-leaves dentate with conspicuously callous-tipped teeth; 



squamellae 0.3-0.5 mm. wide. 3. G. lulea. 



Stem-leaves sinuate-denticulate or entire; squamellae 0.5-0.8 mm. 



wide. 4. G. chrysantha. 



Disk purplish or purplish-brown. 

 Branches divergent-ascending. 



Heads long-peduncled; branches slender. 5. 



Heads very short-peduncled. 6. 



Branches erect, stiff; heads usually short-peduncled. 7. 



Fimbrillae of the receptacle setiform or subulate, mostly surpassing the 

 achenes. 

 Lobes of the disk -corollas acuminate, covered externally with monili- 

 form hairs. 

 Herbaceous; leaves thin. 

 Perennials. 



Involucral bracts villous and ciliate. 8. 



Involucral bracts strigose, not ciliate. 9. 



Annuals. 



Disk yellow. 10. 



Disk purple. 



Squamellae rather narrowly lanceolate, gradually attenu- 

 ate into the awn; leaves densely short-hairy beneath, 

 the lower inclined to be round-lobed and the upper 

 acute. 

 Squamellae ovate or ovate-lanceolate, abruptly acumi- 

 nate into the awn; leaves sparingly long-hairy, the 

 lower acutely lobed and the upper acuminate. 

 Suffruticose; leaves fleshy. 

 Lobes of the disk-corollas short and broad. 



Plants hirsute or villous; leaves not coriaceous, nor conspicuously 

 punctate; caudex, if any, neither very thick nor multicipital. 

 Achenes glabrate above; rays purple or maroon. 



Annual; bracts ciliate; rays more than 1 cm. long. 14. 



Perennial; bracts not ciliate; rays less than 1 cm. long. 15. 



Achenes densely villous all over; rays yellow except in G. 

 nervosa. 

 Pappus-squamellae lanceolate, awn-pointed. 



Disk purple or brown; leaf -segments more or less ascend- 

 ing. 

 Leaves linear or narrowly linear-oblanceolate in 



outline, entire or with a few linear lobes. 16. G. linearis. 



Leaves oblanceolate or lanceolate in outline. 



Leaves except the earliest ones pinnatifid with 

 narrow divisions. 

 Ligules yellow, not strongly veined; disk- 

 corollas with purple limb; pappus much 

 exceeding the hairs of the achenes. 17. G. pinnatifida. 



G. lanceolata. 

 G. fastigiata. 

 G. rigida. 



G. arislata. 

 G. Hallii. 



G. villosa. 



11. G. pulchella. 



12. G. Drummondii. 



13. G. picta. 



G. Amblyodon. 

 G. mexicana. 



