Slanke sleutelbloem / primula elatior
Primula elatior, the oxlip (or True oxlip), is a flowering plant in the genus Primula, found in nutient- and calcium-rich damp woods and meadows throughout Europe eastwards to Altai Mountains and as far north as Scandinavian Mountains in northern Norway and on the Kola Peninsula in Russia. In the British Isles, it is found only in the east, and mainly in East Anglia.
It is a low growing herbaceous perennial plant with a rosette of leaves 5-15 cm long and 2-6 cm broad. The deep yellow flowers are produced in the spring between April and May; they are in clusters of 10-30 together on a single stem 10-30 cm tall, each flower 9-15 mm broad.
It may be confused with the closely related Primula veris (cowslip) which has a similar general appearance although the oxlip has larger, pale yellow flowers more like a primrose, and a corolla tube without folds.