- Name also: Oneflower Fleabame, One Flower Fleabane, One-flower Fleabane, Dwarf Fleabane
- Family: Daisy Family – Compositae, subfamily Asteroideae
(formerly Aster Family – Asteraceae)
- Growing form: Perennial herb.
- Height: 5–15 cm (2–6 in.). Sometimes many-branched. Stem branchless, sometimes arching, gray-haired, often reddish.
- Flower: Single flower-like 10–15 mm (0.4–0.6 in.) capitula surrounded by involucral bracts. Capitula’s ray-florets white, later pale purple, tongue-like; intermediate florets lacking; disc florets yellowish, tubular, small. Stamens 5. Pistil of 2 fused carpels. Involucral bracts overlapping, same length, with white or purplish hairs throughout or only at base. Capitulum solitary terminating stem.
- Leaves: In basal rosette, alternate on stem, Rosette leaves stalked, stem leaves stalkless. Blade lanceolate–narrowly obovate, with entire margins, rosette leaf round–with notched tip, at most with small bristle, virtually glabrous, stem leaves hairy.
- Fruit: Flat, hairy, brownish yellow, 1–2 mm (0.04–0.08 in.) long achene, tip with yellowish-reddish brown unbranched hairs.
- Habitat: Fell tundra snow-bed sites, stream banks, meadows, also forest belt.
- Flowering time: July–August.
Of the four fleabanes that grow in Finland, half would not survive were it not for the large fells of Enontekiö which rise over a kilometre high in the far north of the country. Alpine fleabane (E. borealis) is very rare and grows on rocky outcrops on the fells, and it can usually be told apart from its relatives on account of its large size. One-flowered fleabane is very much like another finger-high species Arctic alpine fleabane (E. humilis), and they grow in the same habitats in the tundra on snow-bed sites, stream banks, rock fissures and fell meadows. Both species are quite common in Enontekiö – Arctic alpine fleabane doesn’t grow anywhere else in Finland but one-flowered fleabane grows rarely in the southern part of Utsjoki alongside Pirkejohka. The easiest way to differentiate between the species is according to their hairs. One-flowered fleabane’s are quite rare and they are white or reddish, while Arctic alpine fleabane’s dense covering is dark purple or almost black. There are also differences in the involucral bracts that surround the capitulum as they repeat the same colour differences.
One-flowered fleabane grows all over the northern Arctic region and in places further south in mountainous regions of central Europe, central Asia and North America. The appearance of the plant varies greatly over such a large habitat. In Finland one-flowered fleabane is usually divided into two subspecies: ssp. uniflorus and ssp. eriocephalus. Ssp. eriocephalus differs from the main form in that it doesn’t grow at all in the large area between Iceland and Alaska and so it is often regarded as an independent species. Its involucral bracts are densely white-haired from base to tip while ssp. uniflorus has involucral bracts that are hairiest at the base of the bracts.