- Family: Pea Family – Fabaceae (Leguminosae)
- Growing form: Perennial herb. Rhizomatous.
- Height: 20–50 cm (8–20 in.). Stem erect, woolly.
- Flower: Corolla zygomorphic, yellowish white, later brownish, 7–9 mm (0.28–0.36 in.) long, fused at base. Petals 5; the upstanding the ‘standard’, the lateral two the ‘wings’, the lower two united to form the ‘keel’, overall shape of corolla being butterfly-like. Calyx 5-lobed, hairy. Stamens 10. A single carpel. Inflorescence a long-stalked, densely spherical, racemose head, often 2 inflorescences together.
- Leaves: Alternate, stalked, stipulate. Blade with 3 leaflets; leaflets elliptic–lanceolate, with finely toothed margins, underside hairy. Stipules mainly united with stalks.
- Fruit: Indehiscent pod, remains inside calyx.
- Habitat: Dry meadows, meadows, rocky outcrops, banks, harbours.
- Flowering time: June–July.
- Endangerment: Near threatened.
Mountain clover seems to have adapted to life in dry, sun-baked areas with its strong rootstock and deep-reaching taproot. Its aerial parts have a biennial cycle: in the first year it develops a leaf rosette and only produces flowering shoots in the following year. It is easiest to spot around midsummer, when its white inflorescence reaches higher than the meadow vegetation that usually surrounds it. It is pollinated by bumble bees and honey bees. Compared to many other clover species the nectar is relatively easy to access – and it probably attracts a correspondingly wider range of pollinators to ensure its seed production.
Mountain clover can be found mainly in the south-western corner of Finland, especially on the Åland Islands and the south-western archipelago right up to the mainland. In the rest of Finland the species has spread randomly with traffic. It is thought that it reached Finland at the earliest during the warm period that followed the Ice Age, during which time the Åland Islands were emerging from the sea to provide a suitable habitat. It is very possible that it only arrived during the Iron Age, however, with the Vikings. Mountain clover could be a beneficiary if the climate becomes warmer in the future as it could spread northwards.
Mountain clover is not easily confused with any other white-flowered clovers. It can be told apart from white clover (T. repens) and alsike clover (T. hybridum) by its hairy calyx, as their calyxes are glabrous.