- Name also: Celery-leaved Buttercup, Crowfoot Buttercup, Blister Buttercup
- Family: Buttercup Family – Ranunculaceae
- Growing form: Annual herb.
- Height: 10–40 cm (4–15 in.). Stem usually erect, thickish, hollow, abundantly branched, not rooting from nodes, grooved, glabrous or upper part hairy.
- Flower: Corolla regular (actinomorphic), light or greenish yellow, 6–10 mm (0.24–0.4 in.) wide; petals 5, approx. same length as sepals. Sepals 5, recurved, hairy, with membranous margins. Receptacle hairy, in fruiting stage particularly high. Stamens many. Gynoecium separate, with many pistils. Inflorescence usually a lax, abundantly-flowered cyme.
- Leaves: Alternate, basal leaves long-stalked, stem leaves stalked–stalkless. Basal leaf blades kidney-shaped, fleshy, glabrous, shiny, with widely tapered base–cordate base, 3-lobed, lobes further 2–3-lobed–toothed. Stem leaf blades 3-lobed, lobes narrow, uppermost blades lobeless, linearly lanceolate, with entire margins.
- Fruit: Elliptic, glabrous, creased, 0.7–1.2 mm (0.028–0.048 in.) long achene, tip with 0.05–0.15 mm (0.002–0.06 in.) long, straight bristle. Achenes in clusters.
- Habitat: Wetlands or shallow waters, ditches, puddles, rock pools on bird rocks, shoreside pastures, around cowsheds, manure piles, dirty water outlets, dumps.
- Flowering time: June–September.
Unlike most Finnish buttercups, celery-leaved crowfoot is an annual. It loves nitrogenous soils and is probably native to rock pools that have been enriched by gull excrement on bird rocks, kelp banks that have built up on the shore, and flooding muddy sandbanks in rich estuaries. The species has gradually conquered Finland pat the halfway mark, moving into culturally influenced habitats from drainage ditch banks to cattle yards and puddles in manure.
Celery-leaved crowfoot is Finland’s most poisonous buttercup, containing an abundance of ranunculin, which has been named after its genus. The first symptoms of poisoning are digestive troubles; when the poison has entered the system it causes dizziness and convulsions and large doses can lead to arrested breathing and circulation. Buttercups taste bad to humans and cattle alike, so celery-leaved crowfoot can usually grow in peace.
The ranunculin that celery-leaved crowfoot contains can also cause bad skin reactions. In the days before the welfare state beggars uses to elicit more sympathy from passers-by by wiping themselves with celery-leaved crowfoot stems and causing rashes and wounds. The same trick has also been used to try and wangle an exemption from national service, which is compulsory in Finland.
Scientific synonym: Ranunculus sceleratus ssp. reptabundus
NOT TRANSLATED YET. Harvinainen, uhanalaiseksi määritelty sammakonleinikki muistuttaa kovasti konnaleinikkiä, mutta on jonkin verran pienempi ja rennompi. Molemmat ovat yksivuotisia, sammakonleinikki kuitenkin usein ylitalvinen. Sammakonleinkin hedelmystö ei ole niin pitkulainen kuin konnanleinikillä ja sen ylimmät varsilehdet ovat leveämpiä. Yhteisillä paikoilla lajit voivat risteytyä.