Ranunculus cassubicus group
- Family: Buttercup Family – Ranunculaceae
- Growing form: Perennial herb.
- Height: 30–70 cm (12–28 in.). Stems 1–3, stem erect, 2–3 times branched, sturdy. Base of stem with, scaly leaves, withering late.
- Flower: Corolla regular (actinomorphic), golden-yellow, 2–3 cm (0.8–1.2 in.) wide; petals 5, usually longer than sepals, sometimes some are partially developed, different sizes, or lacking. Sepals 5, partly hairy. Receptacle 5–11 mm (0.2–0.44 in.) long, densely haired. Stamens many. Gynoecium separate, with many pistils. Inflorescence a lax cyme, flower-stalk glossy.
- Leaves: Alternate, basal leaves 1–2, long-stalked, stem leaves stalkless. Basal leaf blades kidney-shaped–round, usually hairy underneath, cordate-based, usually lobeless (sometimes shallowly 3-lobed), with toothed–serrated margins. Stem leaf blades lobed until base, lobes lanceolate, with toothed margins, teeth around the same size.
- Fruit: Hairy, 2–3 mm (0.08–0.12 in.) long achene, tip with 1.3–2 mm (0.052–0.08 in.) long bristle. Achenes in clusters.
- Habitat: Broad-leaved forests and old parks.
- Flowering time: May.
Kashubian buttercups burst into flower at the end of spring. The flower attracts pollinators, but the seed subject develops regardless without fertilisation, and the new plants are clones of their parents. Every mutation in the parent plant is passed on to its descendants and this new independent form constitutes a microspecies. In Finland there are dozens of these asexual microspecies that propagate themselves apomictically. There do not differ much from each other, but differences can be seen in the way the leaves are lobed. Other apomictic buttercup groups are the goldilocks (R. auricomus), R. fallax and R. monophyllos groups.
Kashubian buttercup means buttercup of Cassubia, the home of the Cassubian tribes in what is now Poland. The species’ habitat stretches from there to the Baltic and northern Russia and south to the Alps and far into southern Europe. In Finland this demanding and heat-loving plant grows at the northern reach of its habitat in rich broad-leaved forests, forest glades and old parks. People have affected the plant’s rich habitats, which has led to its decline.