342 COMPOSITE 



HELIANTHUS 



H. Douglasii T. & G. 1. c. Stems hirsute with spreading hairs, at least 

 above, 1-4 feet high, striate-angled, leafy: leaves oblong-lanceolate, acutish, 

 nearly sessile, triple-nerved, rough-pubescent, 2-4 inches long : bracts of 

 the involucre linear-lanceolate to subulate, 6-9 lines long : rays an inch long : 

 disk nearly an inch broad: achenes obovate, more or less ciliate, fringed: pap- 

 pus a pair of elongated awns with more or less chaffy' dilated base, or some- 

 times reduced to this base, and with mostly conspicuous squamellae. Dry 

 grounds eastern Oregon to British Columbia. 



43 HELIANTHUS L. Gen. n. 979. (sunflower.) 



Erect annual or perennial herbs with simple leaves and large 

 heads of yellow flowers, or those of the disk sometimes brown 

 or purple. Involucre hemispherical or depressed; its bracts 

 imbricated in several series. Eeceptacle flat to conic, chaffy: 

 the chaff subtending and more or less embracing the achenes. 

 Bay-flowers neutral: those of the disk perfect and fertile , with 

 short proper tube and 5-toothed limb. Anthers entire or min- 

 utely 2-toothed at the base. Style-branches tipped with hir- 

 sute appendages. Achenes thick, oblong or obovate, compress- 

 or somewhat 4-angled. Pappus of 2 scales or awns, or some- 

 times with 2-4 additional ones, deciduous. 



§ 1 Annuals. Involucre spreading, its bracts attenuate to 

 a point. Disk-flowers brownish or dark purple. Receptacle 

 flat or nearly so. Leaves petioled, 3-ribbed from or near the 

 base, all but the lower usually alternate. 



H. amnios L. Sp. ii, 904. Stems hispid or scabrous, stout, branched 

 above, 2-6 feet high, or in cultivated forms sometimes 15 feet high : leaves 

 all but the lowest alternate, broadly ovate, petioled, 3-nerved, dentate or den- 

 ticulate, acute at the apex, rough on both sides, sometimes pubescent beneath 

 cordate at base, 2-12 inches long: bracts of the involucre hispid and hispid- 

 ciliate, the outer ovate and abruptly attenuate to a stout bristle; the inner 

 lanceolate and attenuate : rays lanceolate, 1-2 inches long : disk an inch or 

 more or in cultivated plants 4-10 inches in diameter : chaff of the receptacle 

 3-cleft: achenes obovate-oblong, appressed-pubescent to nearly glabrous. On 

 sanely banks and plains, Brit. Columbia to California and Minnesota. 



H. petiolaris Nutt, Journ. Acad. Philacl. ii, 115. Stem strigose-hispid or 

 hirsute. 1-3 feet high, simple or branched: leaves all but the lowest alternate, 

 petioled, oblong or ovate to lanceolate, rough on both sides, usually paler 

 beneath, 1-3 inches long, entire or denticulate, mostly narrowed at the base 

 to a long and slender petiole: bracts of the involucre lanceolate or oblong-lan- 

 ceolate, with acute and niucronate or sometimes more attenuate tips, seldom 

 at all ciliate; rays oblong, 12-18 lines long: disk 6-10 lines in diameter: chaff 

 of the receptacle 3-toothed, not longer than the corollas : achenes villous-pu- 

 bescent. On dry prairies, Washington to Arizona Minnesota and the North- 

 west Territory. 



H. exilis Gray Proc. Am. Acad, vi, 545, More or less hirsute: stems 

 slender, 1-2 feet high, branching: leaves linear-oblong or lanceolate, nearly 

 entire, obscurely 3-nerved at base, tapering into a short petiole: heads small, 

 on slender sometimes leafy-bractcd peduncles: involucre loosely hirsute, its 

 bracts linear-lanceolate, attenuate -acuminate: rays 5-8: chaff of the receptacle 

 produced into an awn-like cusp which equals or surpasses the dark-purple 

 corollas: achenes nearly glabrous : pappus of 2 ovate-lanceolate chaffy scales. 



