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 sandy commons, or waste broken ground, or where the ground has been flooded. The habit is erect. The stems are branched, and numerous. The leaves are narrow, linear to lance-shaped. The flowers are pale-pink. The parts are in fours or fives. The flower-stalks are slender. The calyx-lobes are erect, awl-like, closely appressed. The corolla-segments are blunt-pointed, half as long as the tube. The stigma is 2-lobed. The capsule is spindle-shaped. The plant is 1-4 in. in height. It flowers late in August and September, and is a herbaceous annual.
Marsh Gentian (Gentiana Pneumonanthe, L.) - The habitat of this plant is moist heaths, turfy heaths, and bogs. The habit is erect, or ascending. The stem is slender, scaly below, usually simple, leafy above. The leaves are linear to oblong, blunt, with 1-3 veins. The flowers are few, terminal or axillary, borne on short stalks, large, deep-blue within, with a broad green band down the centre of each lobe. The calyx is inversely conical, has 2 bracts, with 5 linear, blunt, equal segments. The corolla is narrowly bell-shaped, with no hairs in the throat. The capsule is stalked. The plant is 4-18 in. in height. It flowers in August and September, and is a herbaceous perennial.