- Family: Buttercup Family – Ranunculaceae
- Growing form: Perennial herb.
- Height: 6–15 cm (2.4–6 in.), in fruiting stage up to 25 cm (10 in.). Stem erect, usually unbranched, scantly bristly, upper part scantly brown-hairy. 2–3 cm long sheaths present at base of stem.
- Flower: Corolla regular (actinomorphic), dark yellow, 18–28 mm (0.72–1.12 in.) across; petals 5, longer than sepals. Sepals 5, densely brown-hairy, long-lived. Receptacle 1.5–5 mm (0.06–0.2 in.) long, glabrous or sparsely hairy at tip. Stamens many. Gynoecium separate, several pistils. Flowers 1–2, solitary, terminating stem.
- Leaves: Alternate, basal leaves 1–5, long-stalked, stem leaves 1–3, stalkless. Basal leaves’ blade kidney-shaped, usually cordate based, 3-lobed, central lobe entire, lateral lobes 2–3-lobed. Stem leaves lobed, lobes narrowly obovate–elliptic.
- Fruit: 1.5–2 mm (0.06–0.08 in.) long achene, approx. 1 mm long, almost straight bristle at tip. Achenes several together.
- Habitat: Fell tundra snow-bed sites, damp hollows, wet rock surfaces, young, dense broadleaved forests, stream banks.
- Flowering time: (June–)July–August.
There’s no proper Arctic tundra in Finland, but the Lappish fells have large areas of tundra above the treeline. The reason for this lack of trees is that the land is too high: as the altitude increases the temperature drops almost 1˚C for every hundred-metre rise, and northern Lapland peaks no longer support trees. Herb-stemmed vegetation is however diverse: apparently, despite the monotony, these areas are comprised of a mosaic of different kinds of habitats and e.g. a number of small buttercup species that have adapted to unique environments grow there.
Snow buttercup grows in snow-bed sites in the high tundra on Enontekiö and Utsjoki Fells and in flood-water sites. The furthest south it grows is Ounastunturi Fell. During its flowering time snow buttercup is only 10 cm (4 in.) high, but its flower, like many other fell species, is noticeably large in relation to the size of the plant as a whole. As the seeds ripen the stem stretches a little more and achenes that are transported on meltwaters sometimes end up a long way downstream to shingly shores. Forest belt vegetation is however without exception short-lived – the climate is too warm for these fell species.
Snow buttercups are very reminiscent of the endangered species sulphur buttercup, which only survives through the summer in damp places. It favours calciphilous surrounding. Sulphur buttercup is one of Finland’s northernmost species, and it only grows in the country’s north-west arm, close to the Norwegian border on the Vardoaivi, Guonjarvárri and Luassonibba Fells, casually also elsewhere. The best way to differentiate between the species is by the basal leaves: the blade on sulphur buttercup is broadly wedge-based and shallowly 5–9-lobed or toothed.