HAPLOPAPPUS HELENIUM 277 



x. Plants sticky-hairy; leaves toothed to 



pinnatifid H. rubiginosus 



y. Plants gray-hairy to smooth ; leaves 1-2- 



pinnately parted H. spinnlosus 



2. Bracts of the involucre not well-imbricated or 



rigid, more or less equal ; pappus white or whit- 

 ish; leaves entire 



a. Heads solitary; rays conspicuous 



(1) Rays 15-20; leaves soft, not persistent 



(a) Plants green, not woolly 



x. Plants soft-hairy or smooth; involucral 

 bracts oblong, the outer leaf-like and 

 very obtuse ; achenes hairy H. pygmaeus 



y. Plants sticky-hairy; involucral bracts 

 lanceolate, acute ; achenes smooth or 

 nearly so H. Lydllii 



(b) Plants woolly or felted, at least the in- 



volucre; leaves narrowly spatulate to 

 linear ; bracts lanceolate, pointed ; 

 achenes silky H. lanuginosus 



(2) Rays 6-15; leaves stiff and persistent; 



achenes hairy; stems nearly leafless, 1- 



headed, 1-6 in. high H. acdulis 



b. Heads in cymes or clusters; rays 12-20, small 



and narrow ; achenes smooth or nearly so ; 

 stems 5-2 ft. high; leaves oblong-ovate to 

 spatulate H. Pdrryi 



3. Bracts of the involucre more or less equal, with 



conspicuous leafy tips or passing into leaves ; 

 pappus soft ; leaves linear, entire ; rays 2-5 or 

 none 



a. Plants densely white-felted ; heads about 1 in. 



high ; rays none H. macronema 



b. Plants not felted; heads 15-18 mm. high; rays 



2-5 or none H. suffruticosus 



HELENIUM Linne 1753 SNEEZEWEED 

 (The Greek name of some plant) 



PL 41, fig. 3. 



Heads with yellow to orange pistillate or neutral ray-flowers, disk- 

 flowers yellow, perfect, achenes top-shaped, ribbed, pappus of 5-8 entire, 

 toothed or awned scales ; receptacle convex to oblong, without chaff, in- 



