This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
The habitat of this Poppy is moist glens, damp rocky places, shady spots. The plant has the rosette habit. There are no hairs on the stem or leaves. There is a stout, thick, branched and tufted rootstock. The roots are thick. The stem is woolly at the base, many-flowered. The leaves are pinnate, with segments deeply divided nearly to the base, distinct or decurrent, and are long-stalked, bluish-green below. The flowers are yellow, large, borne on long stalks. The sepals are hairy. The petals are rounded. The style is short, the stigma pin-headed, with 4-6 rays. The capsule is 4-6 valved, ribbed, smooth, elliptic to oblong, beaked. The seeds are black or brown, netted. The plant is 1-2 feet high, flowering from June to August, and is a herbaceous perennial.