Helianthus giganteus

Linnaeus

Sp. Pl. 2: 905. 1753.

Common names: Giant or tall sunflower hélianthe géant
Endemic
Synonyms: Helianthus alienus E. Watson Helianthus validus E. Watson
Treatment appears in FNA Volume 21. Treatment on page 165. Mentioned on page 147, 163.

Perennials, 100–400 cm (rhizomatous). Stems (usually reddish) erect, hairy. Leaves cauline; mostly alternate; petioles 0–1.2 cm (ciliate); blades (3-nerved from bases) lanceolate to lanceovate, 7–20 × 1.2–3.5 cm, bases cuneate, margins serrulate to subentire (± flat), abaxial faces scabrous or ± hirsute, sometimes glanddotted. Heads 1–12. Peduncles 8–12 mm. Involucres hemispheric, 10–24 mm diam. Phyllaries 20–25 (loose or spreading), linear, 8–15 × 1.2–2 mm, (margins usually ciliate) apices acute to attenuate, abaxial faces sparsely strigose, not glanddotted. Paleae 7–9 mm, entire or ± 3-toothed (apices acute, hairy). Ray-florets 12–20; laminae (often pale-yellow) 15–25 mm (abaxial faces not glanddotted). Disc-florets 60+; corollas 5–6 mm, lobes yellow; anthers dark-brown or black, appendages dark. Cypselae 3–4 mm, glabrate; pappi of 2 aristate scales 2.4–3 mm. 2n = 34.


Phenology: Flowering late summer–fall.
Habitat: Usually wet, open sites
Elevation: 10–600+ m

Distribution

V21-398-distribution-map.gif

N.B., Nfld. and Labr. (Nfld.), N.S., Ont., Que., Conn., Del., D.C., Ga., Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Miss., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Vt., Va., W.Va., Wis.

Discussion

Helianthus giganteus was probably introduced in Newfoundland. It intergrades with H. nuttallii and H. grosseserratus; it is distinctive in its hairy, reddish-colored stems, dark anther appendages, and prominent setae on the petioles. The natural hybrid of H. giganteus with H. grosseserratus has been called H. luxurians E. Watson (R. W. Long 1954). Hybrids of H. giganteus with H. divaricatus have been referred to as H. ambiguus (Torrey & A. Gray) Britton and H. ×divariserratus R. W. Long (Long 1954).

Selected References

None.

Lower Taxa

None.
... more about "Helianthus giganteus"
strigose +, hirsute +  and scabrous +
not tailed +, rounded +  and obtuse +
black +  and dark-brown +
pale +  and dark +
connate +  and distinct +
subequal +
scarious +
usually ovate +  and lanceolate +
usually deltate +  and lanceolate +
spiciform +, paniculiform +  and corymbiform +
indeterminate +  and determinate +
Edward E. Schilling +
Linnaeus +
cuneate +
7 cm70 mm <br />0.07 m <br /> (20 cm200 mm <br />0.2 m <br />) +
lanceolate;lanceovate +
1.2cm;3.5cm +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
barbellulate +  and barbellate +
Giant or tall sunflower +  and hélianthe géant +
reddish +  and yellow +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
compressed +  and obpyramidal +
fertile +  and bisexual +
fertile +  and bisexual +
N.B. +, Nfld. and Labr. (Nfld.) +, N.S. +, Ont. +, Que. +, Conn. +, Del. +, D.C. +, Ga. +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, N.J. +, N.Y. +, N.C. +, Ohio +, Pa. +, S.C. +, Tenn. +, Vt. +, Va. +, W.Va. +  and Wis. +
10–600+ m +
hairy +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Usually wet, open sites +
in more or less corymbiform , paniculiform or spiciform , arrays +  and singly +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
1 cm10 mm <br />0.01 m <br /> (2.4 cm24 mm <br />0.024 m <br />) +
hemispheric +
1.5 cm15 mm <br />0.015 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
sessile +  and petiolate +
triangular +
serrate +  and entire +
serrulate +  and subentire +
2-carpellate +
3-toothed;entire +
0.7 cm7 mm <br />0.007 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
persistent +
coroniform +
0.8 cm8 mm <br />0.008 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
0 cm0 mm <br />0 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
Flowering late summer–fall. +
0.8 cm8 mm <br />0.008 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
20 +  and 25 +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
bearing subulate enations +, hairy +  and bristly +
flat;slightly convex +
aristate +
0.24 cm2.4 mm <br />0.0024 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
exalbuminous +
procumbent +  and decumbent +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Helianthus alienus +  and Helianthus validus +
Helianthus giganteus +
Helianthus +
species +
campanulate +
toothed +  and entire +
300 cm3,000 mm <br />3 m <br /> (500 cm5,000 mm <br />5 m <br />) +
100 cm1,000 mm <br />1 m <br /> (400 cm4,000 mm <br />4 m <br />) +
shrub +  and subshrub +