Helianthus Compositae 973 



converging with the midrib less than 1 cm above the base; 

 petioles generally less than 1 cm long; pubescence of peduncles 

 and midribs generally spreading; peduncles generally short, 

 robust, conspicuously clavate; bracts linear-lanceolate, lanceolate 

 or narrowly ovate, very loose, sometimes recurving, about as 

 long as the disk or a little longer; plants generally 7-10 dm 

 high ; stems scabrous-hispid, scabrous-hirsute or sometimes nearly 

 smooth, the pubescence on the stems spreading or even retrorse 



on the lower internodes 13. H. hirsutus. 



Plants not as above; leaves on short or long petioles, usually long- 

 decurrent at the base; peduncles rarely with a spreading pubes- 

 cence. 

 Margins of leaves generally coarsely and regularly dentate-serrate; 

 median and lower leaves large, usually ovate, sometimes nar- 

 rower, long taper-pointed at the base, the lateral nerves con- 

 verging with the midrib within the decurrent base; petioles 

 usually 2.5-8 cm long, measured from the convergence of the 

 lateral veins to the base of the petiole; upper leaves smaller, 

 sessile or on short, decurrent petioles. 

 Stems smooth at least below, usually green; leaf blades thin, 

 generally subglabrous beneath, the hairs restricted mostly to 

 the principal veins and closely appressed, sometimes the 

 lower surface rather closely pubescent with short, ascending 

 hairs; yellow glands on the lower surface of blades usually 

 lacking; heads small, the disk usually less than 1.5 cm wide; 

 bracts loose and many recurving, generally as long as or 

 longer than the disk; plants usually of dry, open woodland. 



14. H. decapetalus. 



Stems scabrous-hispid, sometimes glabrescent except the in- 

 florescence, usually reddish, especially in the inflorescence 

 or greenish yellow throughout; leaf blades firm, the lower 

 surface generally densely covered with short, erect or semi- 

 erect hairs and yellow glands; heads usually rather large, 

 the disk 1-1.5 cm wide; bracts exceedingly variable, usually 

 linear-lanceolate, loosely appressed but some widely spread- 

 or recurving, as long as or much longer than the disk, some- 

 times wider and shorter and much resembling those of 

 Helianthus rigidiis, at least the inner ones dark colored, some- 

 times almost black; inflorescence varying greatly in size but 

 usually large, the leaves always alternate, the internodes 

 usually more or less zigzag, and the branches usually 

 more or less compressed; roots often bearing tubers; plants 



usually of moist, open, sunny places 15. H. tuberosus. 



Margins of leaves more or less irregularly and shallowly serrate, 

 or nearly entire; median and lower leaves usually ovate- 

 lanceolate, rarely ovate or lanceolate, usually large, thick, firm, 

 opposite, with a short or long tapering base, the lateral veins 

 converging with the midrib within the decurrent base; lower 

 surface of blades more or less densely covered with short hairs, 

 these sometimes strumose in part, rarely sparsely pubescent, 

 upper leaves sessile or subsessile; stems usually glabrous and 

 and often glaucous, rarely scabrous at least above, generally 

 green; heads of medium size, the disk usually about 1 cm 

 wide or up to 1.5 cm wide; bracts usually broadly lanceolate, 

 acuminate or rarely merely acute, usually shorter than the 

 disk or some of them as long as or longer, loose and usually 

 a few more or less spreading; rays 9-20, usually conspicuous; 

 roots never thickened or tuberous 16. H. strumosus. 



