Helianthus decapetalus
Helianthus salicifolius
hélianthe à dix rayons, thin-leaf sunflower
willowleaf sunflower
erect, glabrous.
(green or purplish) erect, glabrous (glaucous).
cauline; opposite (proximal or all) or alternate (distal);
petioles (1–)2–5 cm;
blades (green, 3-nerved distal to bases) lanceolate to ovate, 7–21 × 4–10 cm, bases rounded to cuneate (often shortly decurrent onto petioles), margins usually serrate (moderately to notably in larger leaves), abaxial faces ± scabro-hispidulous, relatively sparsely gland-dotted.
cauline; alternate;
sessile or subsessile;
blades linear to lance-linear, 8–21 × 0.2–1.2 cm, bases ± attenuate, margins slightly serrulate to subentire (flat), abaxial faces glabrate, gland-dotted.
2–12 cm (not gland-dotted).
2–6 cm.
campanulate, 10–18 mm diam.
8–12;
laminae 20–25 mm.
10–20;
laminae 28–35 mm (apices often bifid).
40+;
corollas 6.5–7.2 mm, lobes yellow;
anthers usually dark brown to black (rarely reddish brown), appendages dark or reddish brown.
50+;
corollas 5.5–6 mm, lobes reddish;
anthers dark, appendages dark (style branches yellow).
20–25 (often reflexed), lance-linear to lanceolate, 11–16 × 2–3 mm (sometimes leaflike, longest surpassing discs by 1/2+ their lengths), (margins ciliate) apices attenuate, abaxial faces strigillose to glabrate, not gland-dotted.
40–50, linear to lance-linear, 12–20 × 1.8–2 mm, (margins ciliate) apices long-attenuate, abaxial faces glabrous or glabrate, not gland-dotted.
3–6(–10).
6–15+.
3.5–5 mm;
pappi of 2 aristate scales 3–4 mm.
4–6 mm, glabrous;
pappi of 2 aristate scales 3–3.6 mm plus 2–8 lacerate scales 0.3–0.5 mm.
-lucres hemispheric, 12–25 mm diam.
8–10 mm, 3-toothed.
8–10 mm, entire or weakly 3-toothed (apices greenish, ± hirsute).
= 34, 68.
= 34.
Helianthus decapetalus
Helianthus salicifolius
Helianthus decapetalus is sometimes confused with Heliopsis helianthoides because of shared habitats and superficial similarities. The tetraploid cytotype of H. decapetalus intergrades (and apparently hybridizes) with H. strumosus, particularly in the southern Appalachians; individual specimens can be difficult to place in one or the other species. In addition to morphologic differences, H. decapetalus usually occurs in more mesic habitats, particularly along watercourses; H. strumosus is found in drier sites such as roadside slopes. Helianthus ×multiflorus Linnaeus is a sterile hybrid, often with “doubled” heads (in which disc florets are replaced by ray florets); it is cultivated and is sometimes included within H. decapetalus, e.g., H. decapetalus var. multiflorus (Linnaeus) A. Gray; its parents are H. decapetalus and H. annuus.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Helianthus salicifolius is found chiefly in the region of the Ozark Plateau. It is cultivated and may occasionally escape. It was recorded from a single site in Chicago, Illinois, where it has now been extirpated.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Go Botany
IL Wildflowers
LA Plants
MD Biodiversity
MI Flora
MO Plants
WildflowerSearch
iNaturalist
USDA Plants Database
KS Wildflowers
