Helenium microcephalum

de Candolle in A. P. de Candolle and A. L. P. P. de Candolle

in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 667. 1836.

Common names: Smallhead sneezeweed
Treatment appears in FNA Volume 21. Treatment on page 433. Mentioned on page 428.

Annuals, 25–120 cm. Stems 1 (2–10), branched distally, moderately to strongly winged, glabrous or sparsely hairy. Leaves glabrous or sparsely to moderately hairy (basal withered by flowering); proximal and mid-blades narrowly elliptic to narrowly oblongelliptic, usually serrate to undulate-serrate, sometimes deeply toothed or laciniate; distal blades narrowly elliptic to narrowly oblongelliptic, serrate to undulate-serrate. Heads 20–300+ per plant, in paniculiform arrays. Peduncles 1.8–8 cm, moderately hairy. Involucres globoid to usually ovoid, 4–12 × 4–12 mm. Phyllaries (connate proximally) moderately hairy. Ray-florets 7–13, pistillate, fertile; corollas usually yellow throughout, sometimes reddish proximally and yellow distally, 2.6–9.1 × 1.5–6.7 mm. Disc-florets 120–400+; corollas yellow to yellow-green proximally, brown to reddish-brown distally, 1.2–2.4 mm, lobes (4–) 5. Cypselae 0.7–1.4 mm, moderately hairy; pappi of usually 6 entire, non-aristate scales (0.2–) 0.3–0.7 mm.

Distribution

V21-1086-distribution-map.gif

Ariz., N.Mex., Okla., Tex., n Mexico

Discussion

Varieties 2 (2 in the flora).

Selected References

None.

Key

1 Peduncles 1–3.5 cm, projecting terminal heads barely beyond foliage; involucres 4–8 × 4–8 mm Helenium microcephalum var. microcephalum
1 Peduncles 1.5–8 cm, usually projecting terminal heads well beyond foliage; involucres 8–12 × 8–12 mm Helenium microcephalum var. oöclinium
... more about "Helenium microcephalum"
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 +
de Candolle in A. P. de Candolle and A. L. P. P. de Candolle +
decurrent +
compound +  and simple +
pinnatifid;lobed;spatulate;ovate;spatulate;ovate;oblong;oblanceolate;linear;lanceolate;elliptic +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
barbellulate +  and barbellate +
Smallhead sneezeweed +
yellow +  and yellow-green proximally +
0.26 cm2.6 mm <br />0.0026 m <br /> (0.91 cm9.1 mm <br />0.0091 m <br />) +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.24 cm2.4 mm <br />0.0024 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.67 cm6.7 mm <br />0.0067 m <br />) +
4-5-angled +  and obpyramidal +
fertile +  and bisexual +
fertile +  and bisexual +
Ariz. +, N.Mex. +, Okla. +, Tex. +  and n Mexico +
gland-dotted +
glabrous or +  and sparsely densely hairy +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
discoid +  and radiate +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
0.4 cm4 mm <br />0.004 m <br /> (3.4 cm34 mm <br />0.034 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
sessile +  and petiolate +
glabrous or +  and sparsely moderately hairy +
deltate +
dentate to pinnatifid or palmatifid +  and entire +
connate +  and distinct +
ovate +, oblong +, oblanceolate +, linear +, lanceolate +  and elliptic +
unequal +  and subequal +
2-carpellate +
persistent +
1.8 cm18 mm <br />0.018 m <br /> (8 cm80 mm <br />0.08 m <br />) +
9 +  and 34 +
in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. +
bearing subulate enations +, hairy +  and bristly +
ovoid;hemispheric;ovoid;hemispheric;globose;conic +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
5 +  and 12 +
non-aristate +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
exalbuminous +
winged +  and branched +
2 (?) +  and 10 (?) +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Compositae +
Helenium microcephalum +
Helenium +
species +
urceolate +  and campanulate +
dilated +
toothed +  and entire +
25 cm250 mm <br />0.25 m <br /> (120 cm1,200 mm <br />1.2 m <br />) +
shrub +  and subshrub +