Genus 64.] 



THISTLE FAMILY. 



425 



10. Helianthus giganteus L. Tall or 

 Giant Sunflower. (Fig. 3907.) 

 Helianthus giganteus L. Sp. PI. 905. 1753. 



Perennial by fleshy roots and creeping rootstocks; 

 stems hispid or scabrous, at least above, branched 

 near the summit, or simple, 3-l2 high. Leaves 

 sessile or short- petioled, firm, lanceolate, very rough 

 above, rough-pubescent beneath, serrate or denticu- 

 late, acuminate at the apex, narrowed at the base, 

 many or all of the upper ones alternate but sometimes 

 all opposite, 2'-6' long, x / z '-\' wide; heads usually 

 several, mostly long-peduncled, i>^ / -2^ / broad; 

 involucre hemispheric, its bracts squarrose, lanceolate- 

 subulate, hirsute or ciliate, commonly as long as the 

 diameter of the yellowish disk ; chaff of the receptacle 

 oblong-linear, acute; achenes oblong, glabrous; rays 

 10-20; pappus of 2 subulate awns. 



In swamps and wet meadows, Maine and Ontario to 

 the Northwest Territory, south to Florida, Nebraska and 

 Louisiana. Stem commonly purple. Aug.-Oct. 



Helianthus giganteus subtuberosus (Bourgeau) Britton. 

 Helianthus subtuberosus Bourgeau; A. Gray, Syn. Fl. 1: Part 2, 276. As synonym. 1884. 



Fleshy roots thick and edible. Leaves more broadly lanceolate and more sharply serrate, 

 largely opposite. Michigan and Minnesota to the Northwest Territory. 



11. Helianthus Maximiliani Schrad. 

 Maximilian's Sunflower. (Fig. 3908.) 



Helianthus Maximiliani Schrad. Ind. Sem. Hort. 



Goett. 1835. 



Perennial by fleshy roots and thickened root- 

 stocks; stems stout, scabrous or hispid below, 2-i2 t> 

 high. Leaves sessile or short- petioled, long-lanceo- 

 late, folding in drying, alternate or the lower op- 

 posite, very rough on both sides, rigid, acuminate 

 or acute at both ends, denticulate or entire, 3 / -7 / 

 long, y^'-iYi' wide; heads few or numerous, 2 / -3 / 

 broad on stout densely rough-pubescent peduncles; 

 involucre hemispheric, its bracts lanceolate, acumi- 

 nate, squarrose, densely strigose-pubescent, often 

 9" long; disk yellowish; rays 15-30; chaff linear, 

 acute, pubescent above; achenes linear-oblong, 

 glabrous or nearly so; pappus commonly of 2 

 lanceolate awns. 



On dry prairies, Minnesota and Manitoba to the 

 Northwest Territory, Nebraska and Texas. Aug.-Oct. 



12. Helianthus grosse-serratus Martens. 

 Saw-tooth Sunflower. (Fig. 3909.) 



Helianthus grosse-serratus Martens, Sel. Sem. Hort. 



Loven. 1839. 



Perennial by fleshy roots and slender root- 

 stocks; stems glabrous, glaucous, branched above, 

 6-io high, the branches usually strigose-pubes- 

 cent; leaves long-lanceolate, slender-petioled, the 

 upper alternate, the lower opposite, long-acuminate, 

 narrowed at the base, sharply serrate, or merely 

 denticulate, the uppermost entire, rough above, 

 densely puberulent or canescent beneath, 4 / -8 / 

 long, %f-x' wide; heads several or numerous, iy& f - 

 3' broad; involucre hemispheric, its bracts squar- 

 rose, narrowly lanceolate, acuminate, hirsute; chaff 

 linear-oblong, pubescent at the summit, acute, of- 

 ten 3-toothed; disk yellowish; rays 10-20, deep 

 yellow; achenes nearly glabrous; pappus of 2 

 lanceofate awns. 



On prairies, Pennsylvania to South Dakota, Missouri 

 and Texas. Reported from further east. Aug.-Oct. 



