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 is shady banks, walls, cottage roofs, dry places, woods, etc. The habit is the rosette habit. The rosettes are stalk-less, oblong, fleshy, and the stolons may be subterranean and autumnal. The root is blunt. The stem is erect, hairless, or downy, slender. The leaves are stalked or in whorls of 3, the edges and veins downy, egg-shaped to lance-shaped, oblong, the base rounded, toothed, opposite, hairless. The buds are nodding, egg-shaped. The flowers are pale-purple. The sepals are lance-shaped. The lobes of the stigma are 4, short, not rolled back. The capsule is finely downy. The plant is 6-24 in. high, flowering in June and July, and is a herbaceous perennial.
The habitat of this plant is roadsides, dry stony places, garden walls, etc. The habit is as in the last. The root is blunt. The stolons are autumnal, the leaves in loose rosettes, spreading. The stem is obscurely angled, round, erect, branched, downy, the hairs short, bent back. The leaves are oblong, lance-shaped, opposite below, toothed, alternate, stalked, narrowed to the base, the lower pairs limp, drooping. The buds are inclined, egg-shaped. The leaf-stalk ends in obscure lines running down the stem. The flowers are numerous, pale-rose. The sepals are broadly linear, with a long narrow point. The stigma lobes are 4, short, and spreading. The capsule is finely downy. The seeds are tubercled, inversely egg-shaped to oblong, nearly acute below. The plant is 9-24 in. high, flowering from July to September, and is a herbaceous perennial.