Part 2, 1915] 



CARDUACKAK : HKLKNIKAK 



121 



radiate. Involucre at first rotate; bracts narrow, linear or subulate in 2 or 3 series, subequal 

 or the inner shorter, at first spreading, usually soon reflexed but in a few species tardily so. 

 Receptacle from convex to ovoid or conic, naked or sometimes with a few bracts between 

 the ray- and disk-flowers. Ray-flowers usually present, in most species pistillate and fertile, 

 in the rest neutral and sterile; ligules large, conspicuous, 3-4-toothed or -lobed, cuneate in 

 outline. Disk-flowers numerous, hermaphrodite and fertile; corollas yellow, brown, or pur- 

 plish; tube very short, not more than one sixth as long as the cylindric or deeply camp mu- 

 late throat; lobes 4 or 5, glandular-hispidulous. Achenes truncately obpyramidal, 4- or 5- 

 angled with as many intermediate ribs, pubescent on the angles and ribs ("glabrous in two 

 species). Pappus of 4-8 thin scarious squamellae, with or without midrib. 

 Type species, Helenium autumnale L. 



Ray-flowers pistillate or wanting. 

 Annuals or rarely biennials. 



Leaves narrowly linear or linear-filiform, not decurrent. 

 Disk yellow; leaves all entire. 



Disk purple-brown; some of the lower stem-leaves pinnately 

 parted. 

 Leaves broader, more or less decurrent. 



Squamellae of the pappus obtuse, pointless, without conspicuous 

 midrib. 

 Rays present. 



Squamellae of the pappus rounded, less than half the 

 length of the achenes. 

 Disk and receptacle elongate in fruit. 

 Disk globular. 



Disk 4—7 mm. broad at maturity. 



Leaves linear-lanceolate or linear; receptacle 

 depressed-hemispheric; squamellae mi- 

 nute. 

 Stem nearly wingless; leaves linear. 

 Stem broadly winged; leaves, at least the 

 lower, linear-lanceolate. 

 Leaves lanceolate; receptacle subconic; squam- 

 ellae nearly half as long as the achenes. 

 Disk 7-10 mm. broad at maturity. 

 Squamellae of the pappus oblong, about half as long as 

 the achenes. 

 Rays wanting. 

 Squamellae of the pappus from acute or mucronate to awn- 

 tipped, usually with a distinct midrib. 

 Pappus less than half as long as the disk -corollas. 



Disk 12-18 mm. broad; plant stout, 5-10 dm. high; 

 heads few on long peduncles. 

 Plant glabrous or nearly so; squamellae acute or 



apiculate; ligules 10-14 mm. long. 

 Plant puberulent; squamellae more or less awn- 

 tipped; ligules 4—6 mm. long. 

 Disk 5-10 mm. broad; plant 2—4 dm. high; heads short- 

 peduncled, corymbose; squamellae scarcely more 

 than apiculate. 

 Lower leaves entire or merely denticulate; disk nearly 



10 mm. broad. 

 Lower leaves more or less pinnately lobed; disk 5-7 

 mm. broad. 

 Pappus at least two thirds as long as the disk -corollas. 

 Plant glabrous; leaves usually entire or dentate. 

 Plant cinereous-puberulent ; lower leaves usually laciniate. 

 Perennials. 



Heads few on long peduncles; leaves strongly ascending, entire. 

 Leaves thin, not at all gummy. 



Heads large, mostly solitary; disk 20-25 mm. broad. 

 Heads smaller, often 2-4; disk 15-18 mm. broad. 

 Leaves thick, somewhat gummy. 

 Heads numerous, corymbose; leaves mostly spreading. 



Pappus about one fourth as long as the glandular-granuliferous 

 disk -corollas, only slightly exceeding the corolla-tube; 

 plant glabrate or minutely puberulent. 

 Leaves ovate, lanceolate, or oblanceolate. 



Disk usually more than 1 cm. broad; leaves usually 

 dentate; ligules gradually tapering below. 

 Ligules 1.5-3 cm. long; leaves long-acuminate, sharply 



toothed. 

 Ligules 1-1.5 cm. long; leaves acute or short-acumi- 

 nate, not sharply toothed. 



1. //. tenuifolium. 



2. II. badiutn. 



3. //. quadridentatum. 



4. H. stenoptcrum. 



5. H . elegans. 



6. H. microcephalum. 



7. H. am phi hoi inn. 



8. //. ooclinium. 



9. //. Thurberi. 



10. //. mexicanum. 



11. //. puberulum. 



12. //. centrale. 



13. H. heterophyllum. 



14. //. lini folium. 



15. //. laciniatum. 



16. //. Bolanderi. 



17. H. rivulare. 



18. H. Bigelovii. 



19. H. altissimum. 



20. H. lati folium. 



