- Name also: Houndstongue, Hounds-tongue, Hound’s Tongue, Dog’s Tongue, Gypsy Flower, Gypsyflower, Rats and Mice
- Family: Borage Family – Boraginaceae
- Growing form: Biennial herb. Taproot dark reddish brown.
- Height: 30–70 cm (12–30 in.). Stem with soft, grey hairs, inflorescence branched, round–slightly angular.
- Flower: Regular (actinomorphic), approx. 6 mm (0.25 in.) wide. Corolla initially bluish violet, later brownish red–dark violet, fused, campanulate (bell-shaped)–funnel-shaped, 5-lobed. Corolla lobes quite round. 5 protruberances in corolla throat. Calyx fused, campanulate (bell-shaped), 5-lobed almost till base, soft-haired. Calyx lobes elliptic. Stamens 5. Gynoecium fused, single-styled. Inflorescence a one-branched scorpioid cyme terminating shoots and branches.
- Leaves: 1st year: large basal rosette. 2nd year: alternate, basal leaves long-stalked, upper stem leaves almost stalkless. Stalk narrowly winged. Blade lanceolate, blunt, both sides soft-haired.
- Fruit: 4-parted schizocarp, tip of carpels fused with body’s conical base. Mericarps cup-like, yellowish brown, outer surface with hooked hairs, 5–8 mm (0.2–0.32 in.) long.
- Habitat: Villages, walls, ruins, roadsides.
- Flowering time: June–July.
- Endangerment: Endangered.
Hound’s-tongue is the only representative of its genus in Finland. (Chinese hound’s tongue, name also Chinese forget-me-not, Cynoglossum amabile may escape from gardens.) Unlike most of its relatives hound’s-tongue emits a fragrance – a stench that smells like a rat’s nest (that’s why the name ‘rats and mice’). It has been planted around houses to keep rats and mice at bay, and it has also been used on boats for the same reason. Anyone can test the power of this beautifully-flowered plant for themselves as it thrives happily in the company of humans. It has become rarer in Finland but still grows abundantly in the oldest inhabited areas in the south-west of the country and especially on the Åland Islands.
As can be deduced from hound’s-tongue’s habitats, it is not native to Finland. Its original habitat stretched to eastern parts of central Europe and the Balkans. Its hook-tipped carpels spread easily over long distances, however, by attaching to people’s clothing and animal fur. One appropriate name that has been used for the plant was ‘monk’s nit’, which is of German origin. This was probably given at the same time as Protestantism arrived in Sweden and when people wanted to ridicule and belittle everything to do with Catholicism and monasticism. Anyone who has ever been near hound’s-tongue plants will not easily forget how easily they stick and how stubborn they are to remove. Hound’s-tongue has also been transplanted on purpose: it was mentioned as a medicinal plant already 7,000 years ago on an Assyrian clay tablet, its root has been used as a sedative and sleep-inducing drug, and it has also been regarded as effective for certain sexually-transmitted diseases. It was later proved that the achenes contain poisonous alkaloids, some of which induce poisoning like South American curare.