Helianthus resinosus
Helianthus maximiliani
resindot sunflower
hélianthe de maximilien, Maximilian sunflower, Maximilian's sunflower
(often reddish or purplish) erect, hirsute or villous.
erect, 5–30 dm, scabrous to scabro-hispidulous.
mostly cauline; mostly alternate;
petioles 0.5–2 cm (broadly winged);
blades lanceolate to ovate, 6.5–20 × 3.2–9 cm, bases gradually narrowed (onto petioles), margins entire or serrate, abaxial faces hirsute to tomentose, gland-dotted.
cauline; mostly alternate;
petioles 0–2 cm;
blades (light green to gray-green, 1-nerved, conduplicate) lanceolate, 10–30 × 2–5.5 cm, bases cuneate, margins usually entire, sometimes serrulate, abaxial faces scabrous to scabro-hispid, gland-dotted.
1–3 cm.
1–11 cm.
hemispheric, 15–27 mm diam.
hemispheric, 13–28 mm diam.
10–20;
laminae (often light yellow) 18–30 mm.
10–25;
laminae (15–)25–40 mm.
90+;
corollas 8–8.5 mm, lobes yellow;
anthers dark, appendages dark.
75+;
corollas 5–7 mm, lobes yellow;
anthers dark brown or black;
appendages usually yellow, sometimes partly dark.
20–30 (squarrose to reflexed, at least tips), lanceolate, 10–21 × 3–5 mm (notably surpassing discs), apices acute to attenuate, abaxial faces hispid to villous, densely gland-dotted (at least toward apices).
30–40, lanceolate, 14–20 × 2–3 mm, (margins ciliate) apices acute to attenuate, abaxial faces canescent, gland-dotted.
1–5.
(1–)3–15 (often in racemiform to spiciform arrays).
5–7 mm, glabrate;
pappi of 2 aristate scales 2.4–2.6 mm.
3–4 mm, glabrate;
pappi of 2 aristate scales 3–4.1 mm.
9–11 mm, 3-toothed (gland-dotted).
7–11 mm, entire or 3-toothed (apices greenish, mucronate, hairy).
= 102.
= 34.
Helianthus resinosus
Helianthus maximiliani
Consistent with its epithet, Helianthus resinosus has abundant subsessile glandular hairs (“resin dots”) on its leaves, phyllaries, paleae, and ray laminae. It intergrades and has been reported to hybridize with H. tuberosus. It is cultivated and usually sold under the long-misapplied name H. tomentosus Michaux.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Helianthus maximiliani is introduced in eastern Ontario and in Quebec. It appears to be native to midcontinental prairie regions and has spread along railroads and highways into all areas of North America. Its wide dispersal may be aided by cultivation for its attractive, showy floral displays. In addition to the usually conduplicate, single-nerved leaves and spikelike arrangement of the heads, it is distinguished by the whitish-canescent indument of the leaves and stems and the long-attenuate phyllaries.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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