972 Compositae Helianthus 



Heads not conspicuously small, more than 8 mm wide. 



Leaves sessile or subsessile, rarely a few on petioles up to 3 mm long. 



Lateral nerves converging with the midrib at the base of the blade, some- 

 times above the base; blades broadly rounded, truncate or subcordate 

 at the base, long attenuate at the apex; stems glabrous and often 

 glaucous, somewhat scabrous above; disk less than 1.5 cm wide; outer 

 involucral bracts usually attenuate; peduncles more or less angled; 

 pubescence of peduncles more or less spreading, shaggy in appearance 

 (due to the various lengths of the hairs and the tendency of some 



to be appressed upward or downward) 7. H. divaricatus. 



Lateral nerves converging with the midrib about a fourth the length of 

 the blade above the base (rarely at the base or obscurely so — Welch 

 no. 881); stems more or less villous with spreading hairs. 

 Leaves rounded at the base, usually slightly clasping, generally all op- 

 posite up to the inflorescence, soft gray-canescent on both surfaces; 

 stems generally densely villous; rays usually 18-26.. .8. H. mollis. 

 Leaves narrowed at the base to a sessile or subsessile base, not at all 

 clasping, at least a few of the upper leaves below the inflorescence 



alternate 9. H. doronicoides. 



Leaves all petiolate, the petioles very short in some species and others with 

 long, margined petioles. 

 Internodes of stem generally more than 20, rarely as few as 15 in de- 

 pauperate plants ; leaves mostly alternate, lanceolate or oblong- 

 lanceolate. 

 Stems glabrous; leaves not scabrous above or only slightly so; lower 

 and median cauline leaves with long tapering bases with petioles 

 usually 1-2 cm long, the upper leaves with short-petioled to sessile 

 blades; blades above the widest portion gradually tapering to the 

 apex in straight lines, except for the short acuminate tip; lower 

 surface of blades densely pubescent with soft, short, more or less 



appressed hairs 10. H. grosseserratiis. 



Stems scabrous or hairy at least above; leaves scabrous above. 



Blades, or at least some of them, conduplicate and often falcate, de- 

 current on the petiole to the base, gray-canescent on both sides; 

 pubescence dense, scabrous-setose; inflorescence racemose; flowers 

 on short peduncles, one terminal and one from each of the upper 



axils; usually flowering late 11. H. Maximiliani. 



Blades neither conduplicate nor falcate; lower and median leaves with 

 short tapering bases with short petioles, the longest not more 

 than 1 cm long, the upper ones sessile; blades gradually tapering 

 to an acuminate point above the widest portion, the margin of 

 one or both sides toward the apex forming a shallow arc; lower 

 surface of the blades sparsely pubescent, usually with long, nearly 

 erect, stiff hairs, sometimes the hairs shorter and subappressed 

 but always stiff; inflorescence not racemose; bracts rather evenly 

 ciliate with multicellular hairs 1 or more mm long (no other 



Indiana species has bracts with such long hairs) 



12. H. giganteus. 



Internodes of stem fewer than 20; leaves mostly opposite; blades ovate, 

 ovate-lanceolate, rarely lanceolate. 

 Bracts closely appressed, ovate, merely acute, generally glabrous on 



the back, shorter than the disk 5a. H. rigidus f. flavus. 



Bracts not as above. 



Plants with the blades of median leaves broadest at the base or a 

 short distance above it, subcordate, truncate, rounded or slightly 

 decurrent at the base, usually thick, strumose-hispid above, hispid 

 beneath or slightly soft-pubescent to the touch, lateral nerves 



