Helianthus bolanderi
Helianthus verticillatus
Bolander's sunflower, serpentine sunflower
whorled sunflower
erect, hispid to hirsute.
erect, glabrous (glaucous).
mostly cauline; mostly alternate;
petioles 1–4 cm;
blades lance-linear or lance-ovate to ovate, 3–15 × 2–6 cm, bases cuneate to truncate, margins usually serrate, abaxial faces sparsely hirsute, gland-dotted.
cauline; usually whorled (3s–6s), sometimes opposite;
sessile or subsessile, petioles 0–1 cm;
blades linear to lanceolate, 7.5–18.5 × 0.7–3 cm, bases cuneate, margins serrulate or entire (flat), faces puberulent (abaxial) or hispid-strumose (adaxial), gland-dotted.
3–13 cm.
1–10 cm.
hemispheric, 17–25 mm diam.
broadly campanulate, 15–20 mm diam.
12–17;
laminae 14–20 mm.
10–19;
laminae 20–26 mm.
75+ (discs usually 2+ cm diam.);
corollas 5–7 mm, lobes usually reddish;
anthers dark, appendages dark (style branches reddish).
150+;
corollas 5–7 mm, lobes yellow;
anthers dark, appendages yellow.
10–18, usually lanceolate to lance-ovate, 9–27 × (3–)3.5–5 mm (often surpassing discs), apices gradually attenuate, abaxial faces hirsute.
45–55, lance-linear, 12–18 × 2–2.5 mm, (margins ciliate) apices long-attenuate, abaxial faces glabrate to sparsely puberulent, gland-dotted.
1–3.
(1–)3–7+.
3.5–4.5 mm, glabrate;
pappi of 2 lanceolate scales 1.7–3 mm.
4–5 mm, glabrous;
pappi of 2 aristate scales 2.2–2.5 mm.
9.5–10.5 mm, 3-toothed (middle teeth subulate, surpassing discs, apices glabrous).
5–8 mm, entire or 3-toothed (apices ciliate).
= 34.
= 34.
Helianthus bolanderi
Helianthus verticillatus
Helianthus bolanderi and H. exilis form a closely related pair of sister species that share the distinctive feature of having the middle teeth of the paleae glabrous and relatively elongated, surpassing the disc florets. As treated here, H. bolanderi corresponds to the “valley weed race” (C. B. Heiser 1949; L. H. Rieseberg et al. 1988); it is separated from the “serpentine foothill race,” here recognized as H. exilis. Heiser proposed that H. bolanderi originated through hybridization between H. annuus and H. exilis; molecular studies by Rieseberg et al. do not support this scheme. In an ironic twist, it appears that H. bolanderi may be undergoing “genetic assimilation” through hybridization with H. annuus (S. E. Carney et al. 2000).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Of conservation concern.
Helianthus verticillatus is relatively uncommon and was recently rediscovered in scattered locations; it is a candidate for federal listing as an endangered species. It has been suggested to be a hybrid of H. angustifolius and H. eggertii or H. grosseserratus; no supporting evidence has been found to corroborate that suggestion.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
