- Latin synonym: Drosera longifolia
- Name also: English Sundew
- Family: Sundew Family – Droseraceae
- Growing form: Perennial herb.
- Height: 6–20 cm (2.4–8 in.). Stem erect, clearly longer than leaves, straight-based, leafless, red scape.
- Flower: Corolla regular (actinomorphic), white, approx. 1 cm (0.4 in,) wide; petals five, 6–7 mm (0.24–0.28 in.) long. Sepals 5. Stamens 5. Gynoecium syncarpous, with 6 styles. Inflorescence 3–6-flowered, one-sided cyme. Flowers open only in sunshine.
- Leaves: In basal rosette, long-stalked, red, ascending oblique. Blade elongated obovate, upper surface with very long, red, glandular hairs that secrete a sticky substance.
- Fruit: Egg-shaped, blunt, glossy, capsule opening into four lobes.
- Habitat: Wet puddles and bogs, swamps and fens, boggy waterside meadows, muddy shores, accretions, gravel pits.
- Flowering time: June–July.
Some of Finland’s best-known carnivorous plants are probably members of the Sundew family that grow in bogs. The Sundew family is comprised of around 90 species, most of which grow in the southern hemisphere. There are only three species in Europe, and these also grow in Finland. In the Bladderwort family (Lentibulariaceae), butterworts and bladderworts are carnivorous: the families are not closely related, however, which implies that carnivorous plants have evolved more than once.
Great sundew’s favoured habitat includes wet swamps and puddles in minerotrophic and ombrotrophic raised bogs. The reddish leaves form a rosette which is so eye-catching that the small white flowers often go unnoticed. It is not so easy to find Sundews in flower either, as they only open up in good weather and even then for only a few hours a day. They close up in cloudy weather, and if the summer is particularly rainy they might never open their flowers even once! Unopened flowers self-pollinate and ensure an abundant crop of seeds. It is worth the effort that Sundews put into seed production, because they are relatively short-lived plants.
Great sundew is the largest of Finland’s three sundews, and it is easy to recognise from its narrow, oblanceolate leaves. A slightly more common species across Finland is common sundew (D. rotundifolia), which has a roundish blade and thrives on different kinds of bog moss hummocks. The hybrid that is produced by great and common sundew grows quite commonly alongside its parents. The third sundew is long-leaved sundew (D. intermedia), which has leaves that are somewhere in the middle of its parents’, but it can be easily differentiated at least when it is flowering because it has a curve-based scape.
Interesting-looking sundews are part of Finland’s folk tradition. In the days when there were believed to be herbs to treat women’s troubles and others that were for men’s problems, great sundew was believed to be specifically for treating women. Its close relative common sundew was believed to have an influence on sexual desire and so solved – if all went well – men’s problems.