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 bogs and marshes. The plant has the sedge habit. The plant is slender. The rootstock is tufted, with no stolons. The stems are 3-sided, smooth, hardly rough above, longer than the leaves. The leaves are narrow, flat. The spike is slender, interrupted, with few or no awl-like bracts. The spikelets are 3-8, egg-shaped, elliptic, touching the lower, often with a bract, male below only. The glumes are pale, the edges broad, membranous, white, with a green keel, blunt, short-pointed. The fruit is erect, acute, plano-convex, flattened, faintly ribbed, the ribs slender, whitish, broadly egg-shaped, as long as the glumes, pale-olive, not winged, with an obscure beak, short, notched, not split, rough on the borders. The nut is egg-shaped, elliptic, lenticular, with a short beak, pale. The styles are persistent. The plant is 1-2 ft. high, flowering in June and July, and is a herbaceous perennial.
Carex buxbaumii, Wahl. (= C. fusca, All. = C. polygama, Schkuhr). - The habitat of this plant is stony banks, spongy bogs, and wet places. The rootstock is short, creeping, stoloniferous. The stems are 3-sided, rigid, leafy below, rough. The leaves are narrow, flat, with reddish-brown, rigid sheaths, the edges net-like, filamentous. The lower bracts are leafy. The spikelets are 3-5, oblong, blunt, close, the lower distant, shortly-stalked. The glumes are rounded, blunt-pointed, the lower longer than the fruit, nearly black, or dark-red-brown, with a green keel which is blunt-pointed. The fruit is bluish-green, oval, ellipsoid, blunt, flattened, 3-angled at length, divided into 2 nearly to the base, shorter than the glumes, with slender ribs. The nut is 3-sided, inversely ovoid, brown, with white dots. There is no beak. The plant is 1-2 ft. in height, flowering in July, and is a herbaceous perennial.
The habitat of this plant is marshy and peaty places. The plant has the sedge habit, and is slender. It is densely tufted. The stems are rigid, 3-sided, slightly rough above. The leaves are long, limp, erect, flat, narrow, the margin rolled back when dry, with long, reddish-brown, shining, filamentous leaf-sheaths, the lower leafless. The fertile spikelets are stalkless, erect or drooping, long, cylindrical, 1-3, sometimes male above, stout, the male spikelets slender, 1-2. The bracts are variable, auricled, the lower leaflike, short. The fruit is rounded to egg-shaped, oblong to elliptic, acute, flattened, veined, closely overlapping, with green nerves, dark-purple, and with a green keel, in 6-9 regular rows, larger than the glumes, and a sheathing beak. The beak is short, notched. The glumes are pitchy, dark-brown, in 8 rows, egg-shaped, blunt, short-pointed, the lower with an excurrent rough midrib. The glumes of the male spikelets are narrow, acute. The nut is inversely egg-shaped, round, short-beaked. The plant is 1-3 ft. high, flowering between May and July, and is a herbaceous perennial.