Author
Mark McConnell
Capitula/heads
Radiate; 6-8 cm across from ray tips; Involucres ± hemispheric, 13–18 mm diam. Phyllaries 25–35, lance-linear to lanceolate, 6–17 × 1.5–3 mm, apices acuminate, surfaces glabrate to sparsely strigose, gland-dotted.
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Common Name(s)
muck sunflower
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Disk Flowers
Disk about 2 cm broad, subhemispheric; disk flowers 100+; corollas 5-5.5 mm, lobes yellow or reddish; anthers dark brown or black, appendages dark; pappus 2 aristate scales 1.5–2.4 mm, readily falling.
Ecology
Perennial; growing in wet mucky soil on open banks, in swales, borders of pinelands, mostly in moist or seasonally wet places, occasionally on the banks of sloughs and in shallow water. Frequently cultivated for ornament in its native range. Often naturalized around human habitations. It sometimes grows intermixed with H. angustifolius with which it may hybridize. Wetland status (FACW).
Family
Asteraceae/Compositae - aster or sunflower family
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Fruit
Achenes (cypselae) dull brown, often mottled with black, glabrous, about 3mm long.
Leaves
Simple,opposite below, alternate above, the larger ones narrowed to a subpetiolar bases, petioles 0.5–1 cm; blades linear-lanceolate to broadly lanceolate, 10-20 cm long overall, 1-3.5 cm broad, margins entire, not revolute or but scarcely so, midvein prominent, lateral veins faintly evident, lower surfaces gland-dotted, upper surfaces pubescent.
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Plant and Stem Features
Perennial, 150-260 cm, rhizomatous. Stem erect, freely branched, 2-3 meters tall, rough-hispid, strigose or hirsute.
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Ray Flowers
12-23; laminae 16-40 mm, abaxially gland dotted; oblanceolate, elliptic, or oblong elliptic, larger ones 1-1.5 cm broad.
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References
Conquist, A. 1980. Vascular Flora of the Southeastern United States, Vol. I, Asteraceae. The University of North Carolina Press, Chapel Hill.
Godfrey, R. K. and J. W. Wooten. 1981. Aquatic and Wetland Plants of
Schilling, E. E. 2006. Helianthus Linnaeus. In: Flora North American North of
USDA, NRCS. 2006. The PLANTS Database (http://plants.usda.gov, 4 December 2006).
Synonyms
none
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