This section is from the book "Wayside And Woodland Blossoms", by Edward Step. Also available from Amazon: Wayside And Woodland Blossoms: A Guide To British Wild-Flowers.
Like the Celandines, this plant was known to our fathers as a Cuckoo-flower; in fact, in many parts of the country its name is still "Cuckoo-flower," but as that title is also given to the Ladies'-smock confusion is caused by its use. It is one of the Campions, a genus of graceful plants that, is included in the Natural Order of the Pinks (Caryophylleae).
The habit of the plant will suggest the Stitchwort, to which it is not very distantly related. It is a perennial plant, delighting in moist places, whether wet meadows, ditch banks or bogs. The leaves that spring directly from the slender rootstock are stalked; those on the reddish stem are not. The calyx is dark red, with purple veins; the rosy petals cut into four eccentric narrow segments. The flowers produce honey, and the stamens come to maturity before the stigmas, thus favouring cross-fertilization. Flowers May to August.
There is another common rosy-flowered Lychnis that occurs in somewhat similar situations. This is:-
Lychnis flos-cuculi - Caryophylleae. The Red Campion (Lychnis diurna), with stem covered with soft hairs, which are sticky near the upper part of the plant. The flower has a singularly neat appearance, altogether lacking the ragged character of flos-cuculi. The petals, instead of being deeply cut, as in that species, are merely divided into two lobes. The calyx is reddish, with triangular teeth. The anthers and stigmas are produced in separate flowers; occasionally flowers may be found with both organs, but one or the other will be undeveloped.
The Red Campion is a plant of the hedge-bank and the copse, where it may be found in flower from June to September. In Cornwall it keeps fully in flower till the end of the year. This page was written there a few days before Christmas, when the fern-clad rocky hedgerows were lit up with great numbers of the flowers of Red Campion and Herb-Robert.
The name Lychnis is from the Greek, Luchnos, a lamp or torch, the application of which is obscure.