Cowslip
Primula veris

Cowslip is one of Ireland's best-known wild perennials. The bright yellow flowers grow in a cluster and droop. The fresh green leaves are in a rosette; they narrow suddenly at the base to a short stalk.
The plant grows in large drifts in rough pastures where there have been cows in the past, and where the soil is limy. Many pastures have been ploughed up lately and re-seeded and cowslips have become scarcer. However there are still some to be seen. The plant is mainly one of the midlands and is rare in the north and the extreme south. In the past it was traditional to make wine out of cowslip flowers.
Caleb Threlkeld mentioned Cowslip in his Synopsis Stirpiu Hibernicarum, published in 1726 - "The Cowslips are Friends to the Nerves," he wrote.
The flowers are out in April and May.
Cowslip grows in Britain, except for some counties of Scotland, and in temperate Europe and Asia.