Their stems are solid, usually more or less triangular, not swollen at the nodes as in grasses; and the sheaths of the leaves which surround the stems are not split. The flowers are in little green or brown spikelets that are either solitary at the top of the stem, or collected into a cluster, spike, panicle, or umbel. Each spikelet is in the axil of a scaly or leafy outer bract, and consists of several scales or glumes, each with a single sessile flower in its axil. The flowers have no perianth, but there are often a few very small scales or bristles at their base. They have two or (generally) three stamens; a one-celled ovary; and a style that is more or less deeply cleft into two or three slender stigmas. The fruit is a small, one-seeded nut, usually flattened in the species which have two stigmas, and triangular where the stigmas are three. [Illustration: THE COMMON SEDGE.] The reader should make himself thoroughly acquainted with the above features of the sedges, in order to avoid any confusion with the rushes, on the one hand, and with the grasses on the other; and he must not be led astray by the fact that some of the sedge family are popularly known as rushes. Of this order the pretty Cotton Grasses (_Eriophorum_) often form a very conspicuous feature of marshes and other wet places. They are tufted or creeping plants with terminal spikelets, very much like those of the other sedges, but their flowers are perfect, and the bristles which represent the perianth grow to a considerable length as the flowering advances, protruding far beyond the overlapping glumes, and at last forming dense tufts of fine cottony hairs. Two species are decidedly common and widely distributed, more especially the Common Cotton Grass (_Eriophorum polystachyon_), which is often so abundant as to give a general whitish appearance to whole patches of boggy land. It is a creeping plant, with solid, rigid, solitary stems, from six inches to over a foot in height; a few shorter, radical leaves; and a few leaves on the stem. Its spikelets, three to twelve in number, form a terminal cluster, the inner ones sessile, or nearly so, and the outer stalked and more or less drooping. They are at first oval or oblong, about half an inch long; but in fruit, usually in the month of June, they form dense cottony tufts from one to two inches in length. [Illustration: THE MARSH SEDGE.] The other is the Hare's-tail or Sheathing Cotton Grass (_E. vaginatum_)--a tufted species, common on boggy moors, with many stems which are round below and triangular above, at first about six or eight inches high, but lengthening as the flowering advances. At the top of each stem is a solitary oval spikelet, of a dark brownish-green colour, over half an inch long, with many straight bristles that eventually form a dense, globular, cottony tuft about an inch in diameter. This is an earlier species, flowering during April and May.