Helianthus debilis |
Helianthus porteri |
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cucumberleaf sunflower, weak sunflower |
confederate daisy, Porter's sunflower |
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Habit | Annuals or perennials, 30–200 cm (taprooted). | Annuals, 40–100 cm. | ||||||||||||||||
Stems | decumbent to erect, glabrous, hirsute, or puberulent. |
erect, usually sparsely strigose, sometimes hispid as well. |
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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 cauline; opposite (proximal) or alternate; petioles 0–0.2 cm; blades (± 3-nerved distal to bases) narrowly lanceolate to linear, 5–11.5 × 0.15–1 cm, bases cuneate, margins entire (often ± ciliate proximally), faces sparsely strigose or scabrous to glabrate, sparsely gland-dotted. |
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Peduncles | 9–50 cm. |
1–10 cm. |
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Involucres | hemispheric, 10–22 mm diam. |
hemispheric, 5–6 mm diam. |
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Ray florets | 11–20; laminae 12–23 mm. |
7–8; laminae (10–)15–20 mm. |
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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). |
30+; corollas 2.8–3.5 mm, lobes yellow; anthers dark, 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. |
11–17, linear, 5.5–8 × 0.8–1.3 mm (margins sparsely hispido-ciliate, hairs 0.5–1.2 mm), apices acute to acuminate, abaxial faces glabrate, not gland-dotted. |
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Heads | 1–3. |
usually 5+. |
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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. |
2.2–2.3 mm, sparsely puberulent (bases and apices); pappi 0. |
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Paleae | 7.5–8 mm, apices 3-toothed (middle teeth acuminate, usually glabrous or hispid, sometimes ± villous or bearded). |
(ovate) 3.5–4.6 mm, entire (1-toothed). |
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2n | = 34. |
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Helianthus debilis |
Helianthus porteri |
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Phenology | Flowering fall. | |||||||||||||||||
Habitat | Granite outcrops | |||||||||||||||||
Elevation | 200–500+ m (700–1600+ 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; GA; NC; 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 porteri was established at Rocky Face Mountain, North Carolina, following its introduction as part of an ecologic experiment. Where it occurs, H. porteri produces conspicuous massed floral displays when in bloom. It is remarkably similar morphologically in its reduced habit, epappose cypselae, conic receptacles, and unlobed, mucronate pales to Heliomeris (Viguiera sect. Heliomeris), and it is treated under Viguiera in most southeastern United States treatments; its style appendages and chromosome number agree with molecular phylogenetic data in placing it within Helianthus. (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. 148. | ||||||||||||||||
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus | Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus | ||||||||||||||||
Sibling taxa | ||||||||||||||||||
Subordinate taxa | ||||||||||||||||||
Synonyms | Rudbeckia porteri, Heliomeris porteri, Viguiera porteri | |||||||||||||||||
Name authority | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 367. (1841) | (A. Gray) Pruski: Castanea 63: 75. (1998) | ||||||||||||||||
Web links |