Helianthus debilis |
Helianthus simulans |
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cucumberleaf sunflower, weak sunflower |
muck sunflower |
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Habit | Annuals or perennials, 30–200 cm (taprooted). | Perennials, 150–260 cm (rhizomatous). | ||||||||||||||||
Stems | decumbent to erect, glabrous, hirsute, or puberulent. |
erect, strigose or hirsute. |
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Leaves | mostly cauline; mostly alternate; petioles 1–7 cm; blades deltate-ovate, lance-ovate, 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 gland-dotted. |
basal and cauline; opposite or alternate; petioles 0.5–1 cm; blades (3-nerved distal to bases) linear-lanceolate to lanceolate, 9–22 cm × 0.7–4 cm, bases cuneate, margins entire or sub-entire (usually slightly revolute), abaxial faces hispidulous to tomentulose, gland-dotted. |
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Peduncles | 9–50 cm. |
1–13 cm. |
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Involucres | hemispheric, 10–22 mm diam. |
± hemispheric, 13–18 mm diam. |
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Ray florets | 11–20; laminae 12–23 mm. |
12–23; laminae 16–40 mm (abaxial faces gland-dotted). |
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Disc florets | 30+; corollas 4.5–5 mm, lobes usually reddish, sometimes yellow; anthers dark, appendages dark (style branches usually reddish, rarely yellow). |
100+; corollas 5–5.5 mm, lobes yellow or reddish; anthers dark brown or black, appendages dark. |
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Phyllaries | 20–30, lanceolate, 8–17 × 1–3 mm, apices acute to long-attenuate, abaxial faces glabrous or ± hispid, not gland-dotted. |
25–35 (loose), lance-linear to lanceolate, 6–17 × 1.5–3 mm, apices acuminate, abaxial faces glabrate to sparsely strigose, gland-dotted. |
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Heads | 1–3. |
1–15. |
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Cypselae | 2.5–3.2 mm, glabrous or sparsely hairy; pappi of 2 lanceolate or lance-linear scales 1.2–2.5 mm. |
2.5–3 mm, glabrous; pappi of 2 (usually unequal) aristate scales 1.5–2.4 mm. |
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Paleae | 7.5–8 mm, apices 3-toothed (middle teeth acuminate, usually glabrous or hispid, sometimes ± villous or bearded). |
5.5–6.5 mm, 3- (or 5-)toothed (distally strigose, gland-dotted). |
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2n | = 34. |
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Helianthus debilis |
Helianthus simulans |
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Phenology | Flowering fall. | |||||||||||||||||
Habitat | Wet soils, ditches, roadsides | |||||||||||||||||
Elevation | 0–50+ m (0–200+ ft) | |||||||||||||||||
Distribution |
AL; CT; FL; GA; LA; MA; MD; MI; MS; NC; NH; NY; PA; RI; SC; TX; VA; VT; WV
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AL; FL; GA; LA; SC |
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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. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Helianthus simulans is similar to H. angustifolius, but much more robust with larger leaves, and to H. floridanus, but with longer and narrower leaves. Some workers have described H. simulans as having yellow disc corollas; this is variable within the species; individuals with reddish disc corolla lobes also occur. It is becoming popular as a garden plant, which may increase its range and may lead to an increase in the occurrence of hybrids with H. angustifolius and H. floridanus. It may be present in Arkansas and Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 21, p. 150. | FNA vol. 21, p. 164. | ||||||||||||||||
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus | Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus | ||||||||||||||||
Sibling taxa | ||||||||||||||||||
Subordinate taxa | ||||||||||||||||||
Name authority | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 367. (1841) | E. Watson: Pap. Michigan Acad. Sci. 9: 363, plate 49. (1929) | ||||||||||||||||
Web links |