GRASS

The presence of gra land depends not so much on soil as on rainfall. Gra es have shallow roots and require frequent showers during their growing season. The earth is naturally divided into woodland, desert, and gra land, but an increase of pasture at the expense of woodland may spoil the pastures of a locality. Nearly all pastures are sown with mixed gra es. Of these Phleum pratense (timothy gra ) is cheap, and used for crops of more than one year’s duration. JLoliwm perenne (perennial rye-gra ) is cheap, and very popular. Alopecurus pratensis (meadow ‘Ox-tail) is expensive, and therefore often adulterated. Gra es are herbaceous monocotyledonous plants with jointed stems, hollow except at the bases of the leaves, They belong to the natural order Tramineae, which includes cereals, gra es, and bamboos. The embryo has one Cotyledon, which remains behind in the seed-coat to absorb the endosperm. The primary root is soon replaced by other roots from the base of the stem. The long, narrow leaves are parallel-veined and have long membraneous sheaths, which enclose the stem, being split on the side opposite the leaf-blade. The leaves are arranged in two opposite series. In the buds the leaves may be rolled or folded. The flowers are arranged in spikelets (7.e are borne on the axis without stalks). These may be grouped together in various ways. If the spikelets are borne on branches of the main axis the inflorescence is a panicle, which is loose as in the oat, or close and cylindrical as in the foz-tail gra . In the wheat the spikelets form a compound spike, The number and character of the flowers in a spikelei vary, and the sepals and petals are absent or scaly. The spikelet bears a number of scales in two rows; the two basal scales have no flowers, and are called glumes. The other scales represent bracts and carry flowers in their axils. They constitute the lower or outer palae or flowering glumes. A long proce , the awn, is sometimes carried by the lower palae, Above the lower palae is the flower, above which there is a scaly bracteole called the upper or inner palae. The flower has three or two stamens inserted below the pistil and borne on long, slender filaments. The anthers are versatile. The pistil consists of one carpel bearing two feathery stigmas, and the ovary contains one ovule, The fruit is a caryopsts (7.¢.) has the seed-coats and fruit-wall fused together, while the seed is albuminous. Two little scales, dodicules, are found at the base of the ovary. The stigma ripens first and the wild gra es are cro -fertilized, but the cultivated cereals are self-pollinated. are wind pollinated. Perennial gra grows either by rhizomes, runners, or suckers, « or,by branching at the base form tufts.