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 plant is damp woods, chiefly in the north. The habit is grass-like. The stem is erect or ascending, round, stout, downy above, shining, brittle. The lower leaves are rough above, long-stalked, heart-shaped, the upper stalkless, egg-shaped. The flowers are white, in a loose-panicled cyme on slender flower-stalks, the petals longer than the sepals, deeply cut, narrow. The sepals are blunt, lance-shaped, with membranous margins. There are 3 styles. The capsule is egg-shaped, as long as or longer than the sepals, the fruit-stalk spreading or turned back. The plant is 1-2 ft. in height. It flowers in May and June, and is a herbaceous perennial.
The habitat of this plant is shady banks. The habit is erect. The plant resembles 5. media, but has larger leaves, with longer stalks, the upper stalkless, the lower inversely heart-shaped. There are also 10 stamens. The seeds have prominently rounded wart-like knobs. The plant is 3-12 in. in height, or more, up to 18 in., and is in flower from April to July, being a herbaceous annual.