- Latin synonym: Harrimanella hypnoides
- Name also: Matted Cassiope
- Family: Heather Family – Ericaceae
- Growing form: Perennial dwarf shrub.
- Height: 5–10 cm (2–4 in.). Stem limp, prostrate, short-branched, woody.
- Flower: Corolla campanulate, white, often red-lobed, 4–5 mm (0.16–0.2 in.) long, fused, 5-lobed. Sepals 5, red. Stamens 10. A single carpel. Flowers solitary terminating short branches, nodding.
- Leaves: Alternate, stalkless, close to stem, with spreading tips, soft, overwintering. Blade needle-like, with entire margins.
- Fruit: Quite round, 3 mm (0.12 in.) long capsule.
- Habitat: Snow-bed sites on fells, seepage surfaces, stream banks.
- Flowering time: July–August.
The Heather family is quite large and includes many plants that like cold, frosty areas. Two representatives of genus Cassiope, which includes about a dozen species, that grow in Finland are moss heather and cassiope (C. tetragona). Moss heather is actually so unique that it is sometimes classified in its own genus Harrimanella. The species are not particularly close to each other and it is highly unlikely that they could ever be confused with each other.
Moss heather is quite common in some parts of the fell area, but it is hardly noticeable outside its flowering time. Its shoots look like moss, even to the extent that when it is not flowering it is hidden completely in the fell’s moss vegetation. Real mosses never flower, however, and when it is blooming moss heather is one of Finland’s most beautiful fell plants with its white, relatively large flowers.
Small and delicate moss heather can be found in low-growing meadows, stream banks, Lappish rock faces and snow-bed sites. It is only common to any extent in northern Lapland, but separate stands further south exist around Pallas-Ounas and in Saariselkä.
When it is not flowering it is a modest-looking plant which jointly holds the record among Finland’s vascular plants for growing at the highest altitude: it grows at the top of Finland’s highest fell, Halti, at a height of 1328 metres, with only two-parted sedge (Carex lachenalii) and rock lichen for company. Compare glacier buttercup.