Greater celandine
Chelidonium majus
Family · Papaveraceae · Poisonous
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This plant, or one that resembles it, is dangerous. Identifying is not authorising: no app has the authority to tell you that you may eat or touch a plant.
Emergency

The yellow poppy of shady walls and ruins, with a sign no other native plant has: break a stem and a bright orange, almost fluorescent latex comes out.
Walls and rocks · Town and roadside · Oak woods · Roadsides and waste ground
Also known asswallowwort, tetterwort
How to tell it
The orange latex is definitive and stains the fingers. Leaves divided into rounded lobes, blue-green beneath, soft-looking. Small yellow four-petalled flowers. Long thin pods, like a crucifer's.
What it is confused with
No dangerous lookalikes known in the Iberian Peninsula.
What it is for
The latex was applied to warts for centuries, which is where the common names come from in several languages. Internal use, no: it contains hepatotoxic alkaloids and there are documented cases of liver injury from celandine preparations. The latex also irritates skin and is dangerous in the eyes.
With documented traditional uses. Not a therapeutic indication and not a dose.
Where it occurs
Each square is an area with recorded observations of this plant. The lighter background is the set of areas where any of the entries has been observed, and serves as a reference. Note what this is not: it is not where the plant lives, it is where people record it, so trails and towns always look fuller than the mountains. Data from GBIF.
Sources
Community
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