COMFOSITAE. 99 1 



Heads 3.5-8 cm. broad ; leaves firm, many of them often alternate. 



Stem scabrous, scabrate or hispid, at least above; leaves sessile or nearly so. 

 Leaves lanceolate, scabrous above, hirsute beneath, fiat. 



Leaves mostly alternate, narrowed at the base. 11. II. gigantcus. 

 Leaves all but the uppermost opposite, obtuse at base. 



12. //. ambiguus. 

 Leaves very scabrous on both sides. 



Leaves elongated-lanceolate, conduplicate, pinnately veined. 



Plant 1-4 m. high ; heads numerous ; leaves mostly alternate. 



13. II. Maximiliani. 

 Plant 4-7 dm. high; heads 1 or 2; leaves all but the upper opposite. 



14. II. Dalyi. 

 Leaves lanceolate to ovate-lanceolate, flat, 3-nerved. 



Leaves narrowly lanceolate, gradually narrowed at the base. 



15. II. stibtuberosus. 

 Leaves ovate-lanceolate, abruptly narrowed at the base. 



16. H. Rydbergi. 

 Stem glabrous ; leaves sessile by a truncate base. 19. H. divaricatus. 

 Stem glabrous; leaves petioled. 



Stem glaucous ; leaves lanceolate, firm. 17. H. grosseserratus. 



Stem not glaucous ; leaves elongated, linear-lanceolate, thin. 



18. H. Kellermani. 

 2. Leaves prevailingly ovate, ovate-lanceolate, or oblong. 

 a. Leaves sessile, or very nearly so. 

 Stem glabrous ; leaves divaricate. 19. H. divaricatus. 



Stem hirsute or hispid ; leaves ascending. 



Leaves cordate-clasping at the base. 20. H. mollis. 



Leaves narrowed from below the middle. 21. H. doronicoides. 



b. Leaves manifestly petioled. 

 Stem puberulent or glabrous. 



Leaves membranous, slender-petioled, sharply serrate. 



Leaves regularly serrate. 22. H. decapetalus. 



Leaves irregularly serrate-laciniate. 23. H. scrophularii/olius. 



Leaves firmer, shorter-petioled, less serrate or entire. 



Bracts of the involucre much longer than the disk. 24. //. trachelii/olius. 

 Bracts of the involucre about equalling the disk. 25. H. strumosus. 



Stem hirsute, hispid, or scabrous. 



Leaves rounded or truncate at the base, short-petioled. 26. H. hirsutus. 

 Leaves, at least the upper, narrowed at the base. 



Bracts of the involucre ovate-lanceolate, appressed. 27. H. laetiflorus 

 Bracts of the involucre lanceolate-acuminate, spreading. 



Leaves villous-pubescent beneath. 28. H. tomentosus. 



Leaves scabrous or puberulent beneath. 29. H. tuberosus. 



1. Helianthus angustifdlius L. Narrow-leaved or Swamp Sunflower. 

 (I. F. f. 3898.) Perennial by slender rootstocks; stem branched above, or simple, 

 slender, often hirsute below, 6-20 dm. high. Leaves firm, entire, sessile, slightly- 

 scabrous, rarely somewhat canescent beneath, 5-17 cm. long, 4-6 mm. wide, the 

 margins revolute when dry; heads usually few, sometimes solitary, 5-7 cm. broad; 

 involucre hemispheric, its bracts linear-lanceolate, acute or acuminate, scarcely 

 squarrose, pubescent; receptacle slightly convex; chaff entire or 3-toothed; rays 

 12-20; achenes truncate, glabrous; pappus usually of 2 short awns. In swamps, 

 Long Island, X. Y.. to Fla., Ky. and Tex., mainly near the coast. Aug.-Oct. 



2. Helianthus orgyalis DC. Linear-leaved Sunflower. (I. F. f. 3899.) 

 Perennial by slender rootstocks; stem branched near the summit, very leafy to 

 the top. 2-3 m. high. Leaves sessiie. entire, remotely dentate and short-petioled, 

 rough with mucronate-tipped papillae, especially on the lower surface, acuminate. 

 1-4 dm. long, 2-8 mm. wide; heads usually numerous, about 5 cm. broad, termi- 

 nating slender branches; involucre nearly hemispheric, its bracts linear-subulate 

 to lanceolate, acuminate, squarrose, ciliate; receptacle convex, its chaff entire, or 

 toothed, slightly ciliate; rays 10-20; achenes oblong-obovate, glabrous, 2-4-awned. 

 On dry plains. Neb, and Colo, to Tex. Sept.-Oct. 



3. Helianthus annuus L. Common Sunflower. (I. F. f. 3900.) Stem his- 

 pid or scabrous, stout, branched above, 1-2 m. hitdi, or in cultivated forms some- 

 times 4.5 m. high. Leaves broadly ovate, petioled. 3-nerved, dentate or denticulate, 

 acute at the apex, rough on both side?, sometimes pubescent beneath, the lower 

 cordate at the base, 7-30 cm. long; heads in the wild plant 7-15 cm. broad; invo- 



