Helianthella uniflora
false sunflower, one-flower helianthella, one-flower little sunflower, Rocky Mountain helianthella
largest at mid stems;
blades usually 3-nerved, usually lanceolate to elliptic, rarely ovate, 12–25 cm, faces puberulent, hirsute, or scabrous.
turbinate to hemispheric or broader, 15–30 mm diam.
11–13(–21);
laminae 15–30(–45) mm.
yellow.
lanceolate to lance-linear (subequal or outer larger, margins sometimes ciliate, faces ± cinereous-pubescent to sparsely puberulent).
usually borne singly, sometimes 2–3+, erect.
strongly compressed, narrowly obovate (margins ciliate, faces strigose);
pappi of 2 ± subulate scales plus 2–4 shorter scales.
chartaceous, relatively firm.
= 30.
Helianthella uniflora
Two infraspecific taxa within Helianthella uniflora may be distinguished; they have been named at varietal rank.
Variety douglasii has stems hirsute; involucres (15–)20–25(–30) mm diam.; outer phyllaries rarely elongated, margins ciliate, abaxial faces sparsely puberulent; ray laminae 30–40 mm; and 2n = 30. It grows in grasslands in the northern Rocky Mountains and on the east side of the Cascade Range (B.C.; Idaho, Oreg., Wash.) at 300–2500 m where it flowers May–Jul.
Variety uniflora has stems sparingly puberulent to scabrous; involucres 15–20(–25) mm diam.; outer phyllaries frequently elongated, margins not ciliate, abaxial faces uniformly cinereous-pubescent; ray laminae 20–30 mm; and 2n = 30. It grows in meadows, sagebrush scrublands, swales, aspen forests, rocky slopes, and spruce-fir forests of the Rocky Mountains, intermountain plateaus, and Great Basin ranges (Ariz., Colo., Idaho, Mont., Nev., Oreg., Utah, Wyo.) at 1500–3400 m, where it flowers (May–)Jun–Jul(–Aug).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
BC
OR
WA
CalFlora
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
