Helianthus debilis |
Helianthus carnosus |
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cucumberleaf sunflower, weak sunflower |
lakeside sunflower |
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Habit | Annuals or perennials, 30–200 cm (taprooted). | Perennials, 10–60 cm, (with crown buds). | ||||||||||||||||
Stems | decumbent to erect, glabrous, hirsute, or puberulent. |
erect, (unbranched) glabrous, eglandular. |
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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. |
mostly basal; opposite (proximal) or alternate; petioles obscure (intergrading with blades); blades lanceolate to lance-linear or linear, 10–25 × 0.5–1.5 cm, bases cuneate, margins entire, faces glabrous, not gland-dotted (cauline 1–5 pairs, smaller). |
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Peduncles | 9–50 cm. |
5–10 cm. |
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Involucres | hemispheric, 10–22 mm diam. |
broadly hemispheric, 17–25 mm diam. |
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Ray florets | 11–20; laminae 12–23 mm. |
12–17; laminae 20–40 mm, (abaxial faces not 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 6–6.5 mm, lobes yellow; anthers dark, appendages yellowish or 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. |
(green with purple veins) 25–30, ovate to lance-ovate, 8–16 × 3–5 mm, apices acuminate, abaxial faces usually glabrous, sometimes puberulent. |
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Heads | 1–3. |
1(–3). |
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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. |
3 mm, glabrous; pappi of 2 aristate scales 1.5–2 mm plus 2–4 erose scales 0.3–0.6 mm. |
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Paleae | 7.5–8 mm, apices 3-toothed (middle teeth acuminate, usually glabrous or hispid, sometimes ± villous or bearded). |
8–9 mm, 3-toothed (middle teeth long-acuminate). |
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2n | = 34. |
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Helianthus debilis |
Helianthus carnosus |
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Phenology | Flowering early–late summer. | |||||||||||||||||
Habitat | Wet prairies, flatwoods | |||||||||||||||||
Elevation | 0–10+ m (0–0+ 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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FL |
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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.) |
Of conservation concern. Helianthus carnosus is distinctive in morphology and is known from relatively few counties in northeastern Florida. (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. 156. | ||||||||||||||||
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus | Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus | ||||||||||||||||
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Subordinate taxa | ||||||||||||||||||
Name authority | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 367. (1841) | Small: Torreya 2: 74. (1902) | ||||||||||||||||
Web links |