This tall, graceful sedge is found in the North Temperate Zone in W. Europe, N. Asia, and N. Africa. It is not found in any early plant-beds. It is found in all parts of Great Britain, except Northants, Glamorgan, Notts, S.E. Yorks, Linlithgow; as far north as the Shet-lands, up to 3200 ft. in the Highlands, and in Ireland.

The Green-ribbed Sedge is an ericetal species found in dry habitats, and it grows in upland stations on the borders of woods, on stony hills, on heaths and moors, as well as in fields, in woodland districts, and on sandy soil by the roadside, up to high elevations.

This is a tall, erect, finally drooping plant, with a slender, graceful stem, with a creeping rootstock. The stems are 3-angled, smooth, with numerous leaves, which are not very long, rigid, keeled, and curved back, flat. The bracts are leaflike.

The spikes are stalked, cylindrical, distant, and the male and female are on different stems. The male flowers are solitary, the female are short, stalkless, or nearly so, distant, the lower ones stalked, the upper included. The sheaths are not so long as the flower-stalk. The spikes are cylindrical, with perigynia with green ribs, and 3-angled, longer than the glumes, which are oblong and compound. The beak is rough alone the margin, and divided into two nearly to the base. The nut is rough and inversely egg-shaped.

This sedge is 1-2 ft. high. The flowers are in bloom in June. The plant is a perennial, propagated by division of the rootstock.

The floral mechanism is that typical of sedges with more numerous and longer female spikelets. There is no doubt that some of the sedges can be pollinated by insects, though usually, as here, by the agency of the wind.

Green ribbed Sedge (Carex binervis, Sm.)

Photo. Horwood - Green-ribbed Sedge (Carex binervis, Sm.)

The nut is indehiscent and falls to the ground close to the plant, or it may be swung on the slender drooping flower-stalks by the wind to a short distance.

Green-ribbed Sedge is a humus-loving plant, and grows in a rich humus soil on heaths or woodland tracts.

The second Latin name refers to the ribbed perigynia.

The plant is often infested by a fungus, Puccinia caricis, one of the "rusts".

Essential Specific Characters: 329. Carex binervis, Sm. - Stem tall, triangular, slender, leaves flat, female spikelets brown, remote, perigynia with two green ribs, nut obovoid.