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 dry pastures, heaths, heathy places. The habit is prostrate (hence depressa). The stem is wavy, wiry, long, much branched, the upper part (like the flower-stalk, sepals, petals, and capsule) sometimes downy. The upper leaves are chiefly opposite, the lower oblong, spoon-shaped, and the upper elliptic, scattered, in 2 rows, or crowded. The bract is shorter than the flower-stalk. The flowers are variable, few in a raceme, terminal and lateral. The calyx wings are as broad as the fruit. The plant is 1-10 in. long, flowering from June to September, and is a herbaceous perennial.