- Name also: Erect Cinquefoil, Common Cinquefoil, Common Tormentil, Septfoil[
- Family: Rose Family – Rosaceae
- Growing form: Perennial herb. Rootstock thick, woody, red-fleshed.
- Height: 10–30 cm (4–12 in.). With many stems. Stem limp–ascending, upper part branched, quite delicate, smoothly haired, up to 50 cm (20 in.) long.
- Flower: Corolla regular (actinomorphic), yellow, approx. 1–1.5 cm (0.4–0.6 in.) broad; petals 4, shallowly notched, base with orange spots, 4–6 mm (0.16–0.24 in.) long, slightly longer than sepals. Calyx 4-lobed; with epicalyx, epicalyx lobes narrow, almost as long as calyx lobes. Stamens usually 16. Gynoecium separate, pistils usually 4–8. Inflorescence an abundantly flowered corymb.
- Leaves: Alternate, basal leaves long-stalked, stem leaves virtually stalkless, stipulate. Blade palmate, with 3 (occasionally) 5 leaflets. Leaflets obovate, only tip with toothed margins, quite glabrous on top, underside densely short-haired. Stipules large, often lobed.
- Fruit: Quite round, ridged, greyish brown achene, several together.
- Habitat: Meadows, pastures, grazing land, roadsides, damp forests, swamps, fens, edges of rich bogs.
- Flowering time: June–August.
Tormentil’s root can weigh up to half a kilo (ca 1 lb) and it contains a lot of tannic acids which means that it has had many important uses in days gone by, such as for tanning leather and dying cloth. The blood-red liquid that trickles from a cut in the rootstock has given tormentil a reputation as a medicinal plant during the age of the Doctrine of Signs. The genus’s scientific name Potentilla comes from the Latin word potens, meaning ‘potent’, and refers to the frequent use of its members for medicinal purposes. The species name erecta refers to the plant’s erect growing form. Tormentil, with its yellow flowers, was believed to increase the amount of milk – and therefore butter – that cows could yield. It can hardly be said to have helped cattle farmers, but it has certainly made use of people and their domestic animals. It was originally limited to swamps and bogs but has found many new habitats connected with agriculture and spread to forest margins, grazing land, slash-and-burn forests and clearings all over Finland. It is the most common plant in its genus in Finland and is common all over the country, except the coast around the Bay of Bothnia.
Tormentil differs from most other members of its genus with its four-leaved corona. Another similar, although rare and endangered meadow plant, trailing tormentil, also named English cinquefoil also grows in the south-west of Finland. Compared to common tormentil its stems are often curved and rooting. Its basal leaves can also have four or five leaflets, and its stem leaves are stalked and have three leaflets at the most. Its stipules are almost always entire, and they are not large-toothed like common tormentil’s. It has a maximum of four yellow flowers, although slightly larger plants might have five. Trailing tormentil grows in the archipelago, most commonly on grazing land on the Dragsfjärd archipelago, but also in Nauvo and Iniö, and separately in Tammisaari. The overgrowth and general decrease of Finland’s traditional landscape and also cross-breeding with common tormentil poses a threat to the future of this already-endangered species.