- Family: Honeysuckle Family – Caprifoliaceae
- Growing form: Perennial dwarf shrub.
- Height: 5–15 cm (2–6 in.). Length up to 1 m. Stem limp, creeping, branched, woody, rooting, glandular-haired. Forms loose, mat-like stands.
- Flower: Corolla campanulate, pink, 5–10 mm (0.2–0.4 in.) long, fused, 5-lobed, lobes round-tipped. Calyx 5-lobed, lobes sharp-tipped. Stamens 4, of which 2 short and 2 long. Gynoecium composed of 3 fused carpels, ovary trilocular, style solitary. Flowers in pairs, nodding, fragrant.
- Leaves: Opposite, short-stalked, overwintering. Blade widely ovate–round, blunt-tipped, sparsely toothed, upper side dark green.
- Fruit: With glandular hairs, spherical, approx. 3 mm long achene, protected by 2 bracts.
- Habitat: Dry and young forest heaths.
- Flowering time: June–July.
The scientific name of twin flower’s genus is a dedication to the man who developed the current classification system of plants and other organisms, Carl von Linné. Twin flower was the great botanist’s favourite plant. Many biology societies have been named in honour of Linné, and Finland’s (founded in 1896) is no exception. Additionally, many little Finnish girls are still named Linnea or Vanamo, the Finnish name for twin flower, each year.
Twin-flower is the treasure of the Finnish forests, common wherever there are conifers, even on pine heaths. Its favourite habitat however is large old fir forests that are still in their natural state, and whose forest floor is linked by a coherent network of moss. In these kinds of places there are no other herbs to compete with twin flower. For plants that are suited to the stable climate of the old forests, almost any kind of ground disturbance is bad news. Forest fires, hoes, fragmenting the forests, treating the earth, fertilization and other human activity can make it virtually extinct. Twin flower survives however, even in renewed forest that has been grassed over, hanging on by the skin of its teeth and awaiting better times.
Twin flower’s creeping stem gets gradually covered in moss, so its length is difficult to notice: they are often two metres long, and in exceptional cases examples have been found of stems up to ten metres long. Erect scapes rise from the stem branches, terminated by two pink flowers. A nodding campanulate corolla protects the easily perishable pollen from the rain. At night the flowers emit a fragrance that is reminiscent of butterfly orchid or lilac, and it seems that almost everyone finds it pleasant. The scent also guarantees that insects notice twin flower: pollination is often carried out by flower flies and also bees and geometrid moths. After pollination the developing achene is covered in sticky glandular hairs so that it sticks easily to passing birds and other animals.