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.
This plant is found in plantations, rock-works, old castle gardens, and subalpine woods in which it has been planted. The habit is prostrate or erect. The stem produces rhizomes bearing stems and leaves. The stem-leaves are twice-ternate, the leaflets egg-shaped, heart-shaped, toothed. The flowers are red, in a short panicle, less than the leaves, as if growing from the leaf-stalk. The 4 sepals fall, and there are 4 petals. The 4 nectaries are cup-shaped. There are 4 stamens. The capsule is a pod, with numerous seeds. The plant is 6-18 in. in height, flowering in June and July, and is a herbaceous perennial.