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 wet, stiff soils, wet places. The plant has the rush habit. The stem is coarsely, deeply furrowed, slender, rigid, bluish-green. The pith is interrupted. The sheaths are dark. The leaves, if present, are reduced. The panicle is much-branched, loose. The perianth-segments are narrow, linear, lance-shaped, awl-like, as long as the capsule. There are 6 stamens. The capsule is black, ovoid, elliptic to oblong, mucronate. The plant is 1-3 ft. high, flowering in July and August, and is a herbaceous perennial.
The habitat of this plant is lake margins, stony and gravelly margins of lakes. The plant has the rush habit. There is a creeping roocsiock. The stems are slender, finely furrowed, wiry, pale-green. The pith is interrupted. There are no leaves. The panicle or cyme is small, stalkless, with few flowers, about the middle of the stem. The perianth-segments are longer than the capsule, lance-shaped, acute. There are 6 stamens, with anthers shorter than the anther-stalks. The capsule is blunt, top-shaped, with a short, abrupt point. The seeds are very small. The plant is 6-8 in. in height, flowering in July and August, and is a herbaceous perennial.