Helianthus laciniatus
Helianthus resinosus
alkali sunflower
resindot sunflower
erect, usually strigose or hispid to glabrate.
(often reddish or purplish) erect, hirsute or villous.
cauline; opposite or alternate;
sessile;
blades (green or grayish, 1- or 3-nerved) lanceolate, 5–9 × 0.5–3.5 cm, bases ± cuneate, margins entire or irregularly toothed to lobed, faces strigose to strumose, gland-dotted (adaxial sometimes glaucous).
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.
4–13 cm.
1–3 cm.
hemispheric, 10–24 mm diam.
hemispheric, 15–27 mm diam.
14–20;
laminae ca. 8–11 mm.
10–20;
laminae (often light yellow) 18–30 mm.
40+;
corollas 4.8–5.8 mm, lobes reddish;
anthers purplish, appendages reddish (style branches yellow).
90+;
corollas 8–8.5 mm, lobes yellow;
anthers dark, appendages dark.
16–21, lanceolate, 6–7.5 × 1.8–2.5 mm (often subequal), (margins ciliate) apices acute, abaxial faces hispidulous or strigose to glabrate, gland-dotted.
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).
1–9.
1–5.
2.7–3.5 mm, glabrate;
pappi of 2(–3) aristate scales 1.4–2.5 mm.
5–7 mm, glabrate;
pappi of 2 aristate scales 2.4–2.6 mm.
7–7.8 mm, entire or 3-toothed (apices obtuse to acute, hispid-ciliate to glabrate).
9–11 mm, 3-toothed (gland-dotted).
= 34.
= 102.
Helianthus laciniatus
Helianthus resinosus
Helianthus laciniatus reaches the northern extent of its range in New Mexico and Texas; it is relatively common in the Chihuahuan Desert areas of Mexico. It is similar to H. ciliaris; it usually has hairy stems as well as denser leaf indument that includes a greater number of subsessile, glandular hairs.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.)
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