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 species is spongy banks of rills, alpine and sub-alpine districts. The plant is almost devoid of hair. The root is creeping. The stems are tufted, ascending, with 2-4 lines of down. There are yellow summer stolons, which are subterranean, slender, bearing rather round, distant scales, and scaly buds in autumn. The stems are erect, wavy, simple, more or less succulent (hence alsincefolium), rooting below. The leaves are opposite as a rule, ovate to narrow-.pointed, with bent-back teeth, shortly-stalked, smooth, shining, rather membranous. The flowers are few, large, purple or rose-colour. The buds are bluish, nodding. The sepals are linear to oblong. The capsule is erect, long, long-stalked, nearly smooth. The seeds are narrow, club-shaped. The plant is 4-12 in. in height. It flowers in July, and is a herbaceous perennial.
The habitat of this Willow-herb is mountain rills of the higher mountains. The plant has the rosette habit, and is prostrate below. The plant is small, somewhat downy. The summer stolons are subterranean, and form a rosette. The barren stems are short, with close upper leaves; the flowering stems are erect, from a short rooting base, with oval or oblong leaves, blunt, narrow below, not long-pointed. The stem has raised lines of down, and is ascending, slender, simple, curved. The leaves are few, pale-green, short-stalked, the upper lance-shaped, elliptic, blunt, entire or toothed, red-tinted, opposite. The buds are blunt, nodding. The flowers are drooping, pale rose-purple, the sepals linear to lance-shaped, acute. The capsule is nearly hairless, the seeds narrow to inversely egg-shaped, pointed below, with a blunt point. The plant is 2-9 in. high, flowering in July, and is a herbaceous perennial.