thinner shoulders of the achene and often with a small accessory palea on each 

 side of each awn, sometimes with small intermediate scales between the 2 prin- 

 cipal awns, all of these pappus members readily caducous. 



An American genus of about 67 species, made difficult taxonomically by the 

 tendency toward hybridization between many of its constituents or at least by 

 the evidence of past genetic intercontamination. 



1. Plants blue-green, strongly glaucous; stems rarely more than 7 dm. tall; leaves 

 nearly all opposite; phyllaries obtuse to acute, glabrous dorsally, 

 white-ciliate, ovate to oblong, closely imbricated, shorter than the 

 disk 1. H. ciliaris. 



1. Plants not strongly glaucous nor blue-green and not with the combination of 



other characters given (2) 



2(1). Disk corollas with red-brown to purple-brown lobes; leaves and the base 

 of the stem scabrous; involucre scabrous; rhizome a short erect 

 crown 2. H. angustifolius. 



2. Disk corollas with yellow lobes (3) 



3(2). Main stem glabrous; leaves narrowly linear-lanceolate, decurrent below 

 confluence of lateral veins into a winged petiole nearly one fourth 

 the length of the blade; rays 20-25 mm. long 4. H. Nuttallii. 



3. Main stem scabrous-hispidulous or at least hirtellous; leaves lanceolate, grad- 



ually acuminate to both ends, sessile; rays 25-35 mm. long 



3. H. Maximiliani. 



1. Helianthus ciliaris DC. Blue-weed. Fig. 764. 



Perennial from slender rhizomes; stems 1 to several, 5-7 dm. tall, glabrous, 

 glaucous; midstem leaves opposite, sessile or very short-petiolate, linear to 

 broadly lanceolate, entire to somewhat pinnately lobed, glabrous and glaucous, 

 conspicuously 3-nerved when lanceolate; heads 12-25 mm. across; phyllaries 

 obtuse, ovate to broadly lanceolate, ciliate, glabrous or slightly puberulent dorsally, 

 5-7 mm. long, about 3.5 mm. broad; rays 12 to 18, about 1 cm. long; disk corolla 

 5-6 mm. long, basally puberulent and yellow, the lobes reddish or sometimes the 

 entire corolla red; pales entire to 3-cuspidate, the tips obtuse to acute and puberu- 

 lent; achenes about 3 mm. long, black or grayish at maturity; pappus of the disk 

 of 2 broadly ovate-acuminate scales; ray pappus absent or of 1 to 3 linear to 

 lanceolate scales. 



Locally abundant near streams or canals, often in subalkaline desert soil in w. 

 Okla. {Waterfall) and Tex. in the Trans-Pecos and Plains Country, infrequent 

 in Rio Grande Plains, N. M. (Quay, Roosevelt, Chaves, Eddy, Otero, Dona Ana 

 and Socorro cos.) and Ariz. (Apache to Mohave, s. to Cochise and Pinal cos.), 

 summer-fall; Kan., Okla., Tex., N.M., Ariz., Chih., Coah., N.L., Tam. and 

 S.L.P. 



2. Helianthus angustifolius L. Fig. 765. 



Perennial herb; roots fibrous; rhizomes few, very slender, 5-15 cm. long; 

 stems 10-17 dm. tall, leafy, mostly simple, usually scabrous, hispid; leaves 

 mostly alternate, variable but mostly linear or narrowly lanceolate, 1-2 dm. long, 

 13-15 (-20) mm. broad, obtuse, sessile, very firm, very scabrous above, pubescent 

 beneath, often with resin-dots; upper branching open-paniculiform; phyllaries 

 narrowly lanceolate, slightly acuminate, usually shorter than the disk, very loose, 

 setose or scabrous, scarcely ciliate; pales 3-cuspidate; disk about 1 cm. across; 

 lobes of disk corolla purple, puberulent; achene slender, glabrous, about 4 mm. 

 long; pappus of 2 lanceolate awns, without intermediate scales. 



Moist places, s.e. Okla. ( Waterfall) and in e. and s.e. Tex., late summer-fall; 

 N.J. s. to Fla., w. to la. and Tex. 



1656 



