Chelidonium majus: foliage and flowers

Chelidonium majus, known in English as "greater celandine" or "tetterwort" and in French as grande chélidoine or herbe aux verrues, is a perennial native to Europe which is sometimes found growing wild in Toronto forests. (It's not listed on SER Ontario's Invasive Exotic Species Ranking for Southern Ontario (PDF).) Its large leaves are deeply lobed; the four-petalled yellow flowers appear in the spring. This plant was photographed in High Park south of the Black Oak Café.