CARDUACEAE 1265 
b. Leaf-blades merely hirsute beneath, 
Leaf-blades narrowed into petiole-like bases. 
Leaves prevailingly alternate. 39. H. giganteus. 
Leaves prevailingly opposite. 
Bracts of the involucreacute or slightly acuminate. 40. H. resinosus. 
Bracts of the involucre with slender, lax tips. 41. H. tracheliifolius. 
Leaf-blades rounded at the base and markedly petioled. 42. H. hirsutus. 
B. Leaf-blades closely sessile and partly clasping. 
Stem glabrous or merely scabrous: leaf-blades 3-ribbed from the 
ase. 43. H. divaricatus. 
Stem hirsute: leaf-blades 3-ribbed from a point below the middle. 44. H. mollis. 
l. Helianthus débilis Nutt. Annual, more or less scabrous. Stems branched at 
the base, the branches decumbent or spreading, 3-9 dm. long: leaves mostly alternate ; 
blades deltoid or somewhat hastate to ovate-lanceolate, 4-8 cm. long, acute or acuminate, 
repand or shallowly and broadly toothed, broadly cuneate to cordate at the base, the 
petioles glabrous or sparingly pubescent, bracts of the involucre lanceolate or linear-lanceo- 
late, 8-10 mm. long, acuminate or subulate-tipped : ray-flowers several ; ligules yellow, 
1-1.5 em. long: disk 1.5-2 em. broad. 
In sandy soil, Florida to Texas. Spring and summer. 
2. Helianthus praécox Engelm. & Gray. Similar to the preceding species in habit. 
Branches, petioles and peduncles hirsute, sometimes copiously so: leaf-blades sharply or 
prominently toothed. 
In sandy soil, near the coast, Florida to Louisiana and Texas. Spring and summer. 
3. Helianthus cucumerifólius T. & G. Annual, similar to the two preceding species 
in habit. Branches mottled: leaves mostly alternate; blades deltoid to ovate or ovate- 
lanceolate, 3-8 em. long, acuminate or sometimes only acute, sharply, irregularly and 
saliently toothed, truncate or subcordate at the base, petioled : bracts of the involucre nar- 
rowly lanceolate to linear-lanceolate, 1-1.5 em. long, attenuate into filiform tips: ray- 
flowers several ; ligules mostly 2-3 cm. long: disks 2-2.5 cm. broad. 
In open woods, Texas. Spring and summer. 
4. Helianthus argophyllus T. & G. Annual, clothed with white, often somewhat 
floccose silky wool. Stems 5-12 dm. tall, branched : leaves alternate except some of the 
lower ones ; blades various, those of the lower leaves very broad, those of the upper leaves 
ovate or lanceolate, 5-15 cm. long, acute, undulate or somewhat serrate, rounded or cordate 
at the base, petioled: bracts of the involucre oblong, ovate or fiddle-sha ed, spreading, 
1-1.5 em. long, acuminate, sometimes sharply so : ray-flowers several ; ligules 2.5-3.5 cm. 
long : disk 2-4 cm. broad. 
In dry soil, Texas. 
5. Helianthus petiolàris Nutt. Annual, more or less scabrous-pubescent. Stem 3- 
9 dm. tall, usually branched, scabrous : leaves alternate above the lower part of the stem ; 
blades oblong-lanceolate to ovate-lanceolate, 3-9 em. long, merely undulate or shallowly 
toothed, narrowly or broadly cuneate at the base, long-petioled : bracts of the involucre not 
hirsute, lanceolate to oblong-lanceolate, 8-12 mm. long, acute or slightly acuminate : ray- 
flowers several ; ligules 1.5-2.5 em. long: disk 2-3 em. broad. 
.In dry soil, Saskatchewan to Minnesota, Texas and Arizona, and rarely naturalized eastward. 
6. Helianthus ánnuus L. Annual, markedly pubescent. Stem hispid or hirsute, 
1-2 m. tall, or taller in cultivation, branched above: leaves mainly alternate ; ae yg 
broadly ovate, 7-30 cm. long, or smaller above, usually slightly acuminate at the apex, e- 
cidedly toothed, those of the lower leaves cordate at the base, those of the upper cuneate : 
bracts of the involucre ovate to oblong or oblong-lanceolate, long-acuminate, hirsute : 
ligules of the ray-flowers 2.5-5 cm. long: disk flat, 3-5 cm. broad. All the parts are often 
much larger in cultivated forms. 
In dry soil, Saskatchewan to Minnesota, Texas and Mexico. Adventive eastward. 
7. Helianthus Floridanus A. Gray. Annual, sparingly pubescent. Stem 1-2 m. 
tall, branched above, smooth and prés almost to the pedune es : leaf-blades thin, nar- 
rowly lanceolate to linear-elliptic, linear-oblong or broadly linear, 4-11 cm. long, ie or 
slightly acuminate at both ends, remotely and shallowly but Leet evenly toothed, : a 
With scattered marginal cilia and spreading hairs along the midrib beneath : bracts o vss 
involucre lanceolate, each prolonged into a slender tip, glabrous except gov the 
larger ones fully 1 em. long : disk dark purple, 1.5-2 cm. broad ; ligules of the ray-flowers 
bright yellow, 2-3 cm. long. 
In sandy, often moist soil, peninsular Florida. Throughout the Den. 
8. Helianthus filifórmis Small. Perennial, glabrous to the inflorescence. ges pu 
dm. tall, simple or sparingly branched above : leaves very numerous : oe ae ] E 
very narrowly linear or coarsely filiform by the revolute margins, 5-10 cm. long, curved, 
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