- 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 highly 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.