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 moist alpine moors. The plant is prostrate, then erect, herbaceous in habit. The rootstock is prostrate, then ascending or subterranean, woody and leafless. The aerial stems are erect, forked above, scaly below, 4-angled. The leaves are few, stalkless, in pairs, oblong or ovate, acute, with 5-7 veins, bluish-green below. The flowers are in terminal umbels, with an involucre of 4 white leaves or bracts, which are acute, petal-like, with few flowers. The flowers are white or dark purple, and very small. The petals and sepals are bent-back. The bracts have purple tips, and serve as petals. The stamens are yellow. The fruit is a drupe, red in colour. The plant is 4-8 in. high, and flowers from July to August, being a herbaceous perennial.