Herbs. Sheaths of leaves not split. Flower in the axil of a single scaly bract (glume).

FIG. 178.-Flower of Cotton Sedge.

Type-Common Cotton Sedge (Eriophorum polystachyum).

A grass-like herb, with an erect stem, bearing several sessile and pedunculate spikes, with long white and cottony hypogynous bristles in fruit.

In this Order the ovary is 1-celled, but the divided style or stigma indicates the syncarpous character of the pistil.

Seeds. Solitary, albuminous, in a 1-celled achene.

The largest genus of the Order is Carex, of which nearly 50 species are native in Britain. Carex differs from the Type in having monoecious flowers, arranged in spikes the male flowers, consisting of 3 stamens, destitute of a perianth, borne in the axil of a scale-like bract,

FIG. 179.-Male flower of Carex.

FIG. 180.-Female flower of same.

FIG. 181.-Vertical section of fruit of same.

called a glume; the female flowers, each enclosed in a flask-shaped loose integument, called the perigynium, which is open at the apex, to allow the stigmas to protrude.

The Papyrus used as paper by the ancients, especially the Egyptians, was prepared from the pith-like tissue of the stem of a large Cyperus.

A common plant in the fens, Scirpus lacustris, is cut for chair-bottoms, baskets, mats, horse-collars, bottlecovers, &c.

The cottony bristles of Cotton Sedge are collected for stuffing pillows. They are not of sufficient staple to be woven like cotton.

The Sand Carex (Carex arenaria), and a grass, the Sea Maram (Psamma arenaria), form long creeping rhizomes, which are highly important in binding the moving sands of dunes and embankments on the sea

coast.

73. Natural Order-Gramineæ. The Grass Family. DISTRIBUTION.-A very large and cosmopolitan Order. Some tropical genera (of Bambuseæ) are arborescent.British genera 42, species 100.

Herbs. Sheaths of leaves split in front (except Common Melick). Flowers sheathed by two-rowed scaly bracts (glumes); innermost glume (pale) 2-nerved.

Type-Common Wheat (Triticum vulgare).

An annual, with an erect unbranched jointed stem (culm), and distichous spicate flowers.

The structure of the flower of wheat is described at pages 44-45.

The table on the next page will serve to show in what particulars several grasses, British and exotic, deviate from the above Type.

The first column gives the name of the species. The second shows the kind of inflorescence, which is generally a panicle, though often compressed, or the branches so short as to resemble a raceme or spike, when it is termed racemose or spicate. The third column gives the number of outer glumes to each spikelet; the fourth indicates the presence or absence of the flowering glume; the fifth the presence or absence of the pale; sixth, the number of lodicules; seventh, of stamens; eighth, of styles.

The species printed in small capitals are Cornproducing or Cereal Grasses, called Cereals, from Ceres, the Roman goddess of Corn.

The sign denotes a striking deviation from the normal structure of Grasses.

The arrangement of the flowers of Barley requires explanation. The 1-flowered spikelets are arranged, three together, on each joint of the axis (rachis) of the inflorescence. In two-rowed Barley, the single floret of the central spikelet only is fertile, the florets of the 2 lateral spikelets being barren; in six-rowed Barley, each of the 3 spikelets contains a fertile floret.

Compare Rye with Barley. They are very similar at first sight, but the spikelets in Rye, instead of being in threes, are arranged singly upon the rachis, as in Wheat, and each spikelet contains 2 lateral fertile florets and a central floret, represented often by a minute rudiment or pedicel simply, which is easily overlooked.

OBSERVE, in any common Grass, the stem, called a culm, usually hollow (fistular), jointed, and with sheathing

FIG. 182.-Ternate one flowered spikelets of Barley.

leaves, the sheath being almost invariably split down the front, and embracing the culm: the ligule, a scale-like

FIG. 183. -Spikelet, dissected, of Vernal Grass. The lowest pair of scales, right and left, are the outer glumes; then come two awned empty glumes; then, to the right, the flowering glume, and, to the left, the small pale; lastly the two stamens and the pistil.