Helenium quadridentatum

Labillardière

Actes Soc. Hist. Nat. Paris 1: 22, plate 4. 1792.

Common names: Longdisk sneezeweed
Treatment appears in FNA Volume 21. Treatment on page 434. Mentioned on page 428.
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Annuals, 30–100 cm. Stems usually 1, branched distally, moderately to strongly winged, glabrous or sparsely hairy. Leaves glabrous or sparsely hairy; blades narrowly elliptic to lance-linear, usually entire; proximal blades sometimes pinnately lobed. Heads 5–15 (–50+) per plant, in paniculiform arrays. Peduncles 3–13 cm, sparsely to moderately hairy. Involucres ovoid to conic, 7–11 (–14) × 6–11 mm. Phyllaries (connate proximally) sparsely to densely hairy. Ray-florets 10–15, pistillate, fertile; corollas yellow, 7–12.4 × 4–8.8 mm. Disc-florets 225–500+; corollas yellow proximally, yellow to brown to reddish-brown distally, 1.1–1.8 mm, lobes 4. Cypselae 0.6–1.2 mm, moderately hairy; pappi of usually 6 entire, non-aristate scales 0.1–0.3 mm. 2n = 26.


Phenology: Flowering Mar–Jun (year round).
Habitat: Sandy or clay soils, ditches, around ponds and lakes, along streams
Elevation: 0–1800 m

Distribution

V21-1089-distribution-map.gif

Ala., La., Miss., Pa., Tex., Mexico, West Indies (Cuba), Central America (Belize), Central America (Guatemala)

Discussion

Helenium quadridentatum is introduced in Pennsylvania.

Selected References

None.

Lower Taxa

None.
... more about "Helenium quadridentatum"
not tailed +, rounded +  and obtuse +
connate +  and distinct +
subequal +
scarious +
usually ovate +  and lanceolate +
usually deltate +  and lanceolate +
paniculiform +
indeterminate +  and determinate +
Mark W. Bierner +
Labillardière +
decurrent +
compound +  and simple +
elliptic to lance-linear +  and elliptic +
pinnatifid;lobed;spatulate;ovate;spatulate;ovate;oblong;oblanceolate;linear;lanceolate;elliptic +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
barbellulate +  and barbellate +
Longdisk sneezeweed +
yellow +  and brown +
0.7 cm7 mm <br />0.007 m <br /> (1.24 cm12.4 mm <br />0.0124 m <br />) +
0.11 cm1.1 mm <br />0.0011 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (0.88 cm8.8 mm <br />0.0088 m <br />) +
4-5-angled +  and obpyramidal +
fertile +  and bisexual +
fertile +  and bisexual +
Ala. +, La. +, Miss. +, Pa. +, Tex. +, Mexico +, West Indies (Cuba) +, Central America (Belize) +  and Central America (Guatemala) +
0–1800 m +
gland-dotted +
glabrous or +  and sparsely densely hairy +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Sandy or clay soils, ditches, around ponds and lakes, along streams +
discoid +  and radiate +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
1.1 cm11 mm <br />0.011 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (3.4 cm34 mm <br />0.034 m <br />) +
0.7 cm7 mm <br />0.007 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
ovoid;conic +
0.6 cm6 mm <br />0.006 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
sessile +  and petiolate +
hairy +  and glabrous +
deltate +
dentate to pinnatifid or palmatifid +  and entire +
connate +  and distinct +
ovate +, oblong +, oblanceolate +, linear +, lanceolate +  and elliptic +
unequal +  and subequal +
2-carpellate +
persistent +
3 cm30 mm <br />0.03 m <br /> (13 cm130 mm <br />0.13 m <br />) +
Flowering Mar–Jun (year round). +
9 +  and 34 +
Actes Soc. Hist. Nat. Paris +
bearing subulate enations +, hairy +  and bristly +
ovoid;hemispheric;ovoid;hemispheric;globose;conic +
5 +  and 12 +
non-aristate +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
exalbuminous +
winged +  and branched +
1 (?) +  and 10 (?) +
hairy +  and glabrous +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Compositae +
Helenium quadridentatum +
Helenium +
species +
urceolate +  and campanulate +
dilated +
toothed +  and entire +
30 cm300 mm <br />0.3 m <br /> (100 cm1,000 mm <br />1 m <br />) +
shrub +  and subshrub +