Helianthus debilis

Nuttall

Trans. Amer. Philos. Soc., n. s. 7: 367. 1841.

Endemic
Treatment appears in FNA Volume 21. Treatment on page 150. Mentioned on page 142, 143, 151, 153.

Annuals or perennials, 30–200 cm (taprooted). Stems decumbent to erect, glabrous, hirsute, or puberulent. Leaves mostly cauline; mostly alternate; petioles 1–7 cm; blades deltate-ovate, lanceovate, or ovate, 2.5–14 × 1.8–13 cm, bases cordate to truncate or broadly cuneate, margins subentire to serrate, abaxial faces glabrate to hispid, not glanddotted. Heads 1–3. Peduncles 9–50 cm. Involucres hemispheric, 10–22 mm diam. Phyllaries 20–30, lanceolate, 8–17 × 1–3 mm, apices acute to long-attenuate, abaxial faces glabrous or ± hispid, not glanddotted. Paleae 7.5–8 mm, apices 3-toothed (middle teeth acuminate, usually glabrous or hispid, sometimes ± villous or bearded). Ray-florets 11–20; laminae 12–23 mm. Disc-florets 30+; corollas 4.5–5 mm, lobes usually reddish, sometimes yellow; anthers dark, appendages dark (style-branches usually reddish, rarely yellow). Cypselae 2.5–3.2 mm, glabrous or sparsely hairy; pappi of 2 lanceolate or lance-linear scales 1.2–2.5 mm.

Distribution

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Ala., Conn., Fla., Ga., La., Mass., Md., Mich., Miss., N.C., N.H., N.Y., Pa., R.I., S.C., Tex., Va., Vt., W.Va.

Discussion

Subspecies 5 (5 in the flora).

C. B. Heiser (1956) placed 8 subspecies in Helianthus debilis; he noted that alternative taxonomic treatments might recognize these in as many as three species, or expand the single species to include H. petiolaris. Later, Heiser et al. (1969) separated three of the subspecies as H. praecox. Isozyme data (R. P. Wain 1982, 1983; L. H. Rieseberg and M. F. Doyle 1989) show that all are closely related. Documented hybridization with H. annuus further complicates the situation. The treatment by Heiser et al. is followed here.

Helianthus debilis is adventive beyond the Atlantic and Gulf coasts of the United States.

Selected References

None.

Key

1 Stems decumbent; peduncles 9–20(–22) cm > 2
1 Stems erect; peduncles (15–)20–50 cm > 3
2 Stems glabrous or puberulent; leaf blades serrulate or shallowly, regularly serrate, abaxial faces sparsely, if at all, gland-dotted Helianthus debilis subsp. debilis
2 Stems hirsute; leaf blades deeply, irregularly serrate, abaxial faces densely gland-dotted Helianthus debilis subsp. vestitus
3 Leaves 8–14 cm; peduncles (relatively slender) 20–40 cm; discs 10–15(–17) mm diam Helianthus debilis subsp. silvestris
3 Leaves 2.5–9 cm; peduncles (not notably slender) 10–50 cm; discs 14–20 mm diam > 4
4 Leaf blades usually deeply, irregularly serrate; peduncles 10–25(–30) cm; ray lami-nae 12–20(–22) mm Helianthus debilis subsp. tardiflorus
4 Leaf blades usually shallowly, regularly serrate; peduncles 25–50 cm; ray laminae (15–)20–23 mm Helianthus debilis subsp. cucumerifolius
... more about "Helianthus debilis"
hispid +, glabrous +  and glabrate +
not tailed +, rounded +  and obtuse +
pale +  and dark +
connate +  and distinct +
3-toothed;acute;long-attenuate +
subequal +
scarious +
usually ovate +  and lanceolate +
usually deltate +  and lanceolate +
spiciform +, paniculiform +  and corymbiform +
indeterminate +  and determinate +
Edward E. Schilling +
Nuttall +
cordate +  and truncate or broadly cuneate +
2.5 cm25 mm <br />0.025 m <br /> - 14 cm140 mm <br />0.14 m <br /> +
ovate;lanceovate;ovate;lanceovate;deltate-ovate +
1.8 cm18 mm <br />0.018 m <br /> - 13 cm130 mm <br />0.13 m <br /> +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
barbellulate +  and barbellate +
reddish +  and yellow +
0.45 cm4.5 mm <br />0.0045 m <br /> - 0.5 cm5 mm <br />0.005 m <br /> +
hairy +  and glabrous +
compressed +  and obpyramidal +
fertile +  and bisexual +
fertile +  and bisexual +
Ala. +, Conn. +, Fla. +, Ga. +, La. +, Mass. +, Md. +, Mich. +, Miss. +, N.C. +, N.H. +, N.Y. +, Pa. +, R.I. +, S.C. +, Tex. +, Va. +, Vt. +  and W.Va. +
hairy +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
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 /> - 2.2 cm22 mm <br />0.022 m <br /> +
hemispheric +
1.2 cm12 mm <br />0.012 m <br /> - 2.3 cm23 mm <br />0.023 m <br /> +
sessile +  and petiolate +
yellow;reddish +
triangular +
serrate +  and entire +
subentire +  and serrate +
2-carpellate +
0.75 cm7.5 mm <br />0.0075 m <br /> - 0.8 cm8 mm <br />0.008 m <br /> +
persistent +
coroniform +
9 cm90 mm <br />0.09 m <br /> - 50 cm500 mm <br />0.5 m <br /> +
1 cm10 mm <br />0.01 m <br /> - 7 cm70 mm <br />0.07 m <br /> +
0.8 cm8 mm <br />0.008 m <br /> - 1.7 cm17 mm <br />0.017 m <br /> +
20 +  and 30 +
0.1 cm1 mm <br />0.001 m <br /> - 0.3 cm3 mm <br />0.003 m <br /> +
Trans. Amer. Philos. Soc., n. s. +
bearing subulate enations +, hairy +  and bristly +
flat;slightly convex +
lance-linear +  and lanceolate +
0.12 cm1.2 mm <br />0.0012 m <br /> - 0.25 cm2.5 mm <br />0.0025 m <br /> +
exalbuminous +
procumbent +  and decumbent +
decumbent +  and erect +
puberulent +, hirsute +  and glabrous +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Undefined - tribe Undefined subtribe Lagasceinae +
Helianthus debilis +
Helianthus +
species +
campanulate +
toothed +  and entire +
300 cm3,000 mm <br />3 m <br /> - 500 cm5,000 mm <br />5 m <br /> +
perennial +  and annual +
30 cm300 mm <br />0.3 m <br /> - 200 cm2,000 mm <br />2 m <br /> +
2 cm20 mm <br />0.02 m <br /> - 20 cm200 mm <br />0.2 m <br /> +
shrub +  and subshrub +