- Name also: Tetterwort, Nipplewort, Swallowwort
- Family: Poppy Family – Papaveraceae
- Growing form: Perennial herb. Strong taproot.
- Height: 40–60 cm (16–25 in.). Lower part of stem and leaf-stalks sparsely long-haired.
- Flower: Regular (actinomorphic), 2–3 cm (0.8–1.2 in.) wide. Petals 4, yellow. Sepals 2, falling as flower opens. Stamens 12–30. Pistil of two fused carpels. Inflorescence a 3–6-flowered, axillary umbel.
- Leaves: Alternate, stalked. Blade pinnate, underside bluish grey and hairy. Leaflets quite round, slightly lobed, lobes blunt-toothed.
- Fruit: Slender, 3–5 cm (1.2–2 in.) long, bivalved, glabrous capsule, resembling a siliqua and opening from the base to the tip. Seeds black with fleshy white appendage (elaiosome).
- Habitat: Garden hedgerows, rocky commons, rocky embankments in lush woods.
- Flowering time: June–August.
Greater celandine is poisonous, especially its reddish yellow latex, which runs from broken parts of the plant’s surface. Its flowers excrete no nectar, rather pollination is carried out by nutrition-hungry insects – self-pollination seems to be possible. Its small, black seeds have a juicy appendage, elaiosome which ants like to eat, and the seeds are dragged along to new habitats as the ants enjoy their meal. Ant-eating birds, such as woodpeckers and wrynecks, might spread the seeds further, but more efficient long-distance spreading is probably carried out by people.
Greater celandine was used in bygone times as a medicinal herb and was possibly also cultivated. It most commonly grows in culturally-influenced places, e.g. old dwelling areas. It can also grow like native species in broad-leaved forests, but if so, not far from civilization. With good luck one can also come across a version of the plant with several petals.