Fig. 3. Spikelet of Awnhss Brome Grass. Natural size. Gl.-Sterile glumes. L. - Lemma.
Spikelets: The ultimate branches of the inflorescence end with so-called spikelets, a kind of partial inflorescence (Fig. 3). At the base of the spikelet are two sterile glumes (Fig. 3, Gl.), though Italian and Perennial Rye Grass have only one. Above them are a number of fertile glumes, called lemmas (Fig. 3, L.), which carry a flower in their axils. Each flower is enclosed by a delicate glume called palea (Fig. 4, Pa.) and consists chiefly of three stamens (Fig. 4, St.) and a pistil with two feathery branched stigmas (Fig. 4, P.). The number of flowers varies in different grasses; Awnless Brome has seven to nine in each spikelet, whereas Red Top has only one. In the latter the whole spikelet consists of the two sterile glumes (Fig. 3, Gl), the lemma (Fig. 4, L.) and the palea (Fig. 4, Pa.) enclosing the flower proper.
Fertilization: Before blossoming the glumes tightly enclose the flowers, and nothing is seen of the stamens and pistil. At flowering time the glumes generally open wide and the stamens and pistil are visible (Fig. 4). Dustlike masses are soon produced from the stamens and carried away by the wind. This is the pollen, which, when caught by the branches of the stigmas, induces the lower part of the pistil or ovary (Fig. 4, O.) to develop into fruit. In wheat, oats and barley the pollen is generally transported to the stigmas before the glumes of the spikelet begin to separate; each flower is Consequently fertilized by its own pollen. This is never the case with the grasses dealt with in the present publication. The stamens are not ready to shed their pollen until after the glumes have separated, and there is thus always a chance for the pistil to be fertilized by pollen from another flower. In many grasses such a cross-fertilization is favoured by the fact that the stamens and pistil of one flower are not ripe at the same time.
Fig. 4. Flower with enclosing glumes of Tall Oat Grass. Four times natural size. L. - Lemma. P. - Stigma. Pa. - Palea. O. - Ovary. St. - Stamen.
Fruit: After fertilization the ovary of the grasses develops into a fruit enclosing a single seed. Properly speaking, the grains of corn, wheat and rye are fruits containing a seed, just as the hazel nut is a fruit enclosing the seed. The hulled seed of Timothy is in reality a fruit containing a single seed. In most grasses the fruit remains enclosed in the glumes and the whole thing is termed seed. This is the case, for instance, in Rye Grasses, Fescues, Blue Grasses, Red Top, unhulled Timothy, etc., the seed of which, properly speaking, is a fruit enclosed in the glumes. The term "seed" being generally applied, it has been used in the description of the grasses to designate the fruit enclosed by the glumes, as it is generally found in commerce.
Agricultural Value: Practically any wild grass will serve, in one stage or another, as food for stock. Even the grasses of deserts, or other inhospitable localities, which are dry, woody and unpalatable the greater part of the year, may, when young or when refreshed by rain, furnish nutritious fodder or pasture. The value of wild grasses, however, is generally considerably lower than that of the cultivated sorts. The latter are better cared for, have readier access to food, less of a struggle for existence, and so are apt to grow more luxuriantly and yield a better quality of hay or fodder.
When attempting to cultivate a wild grass, or when growing a cultivated variety, one should consider its suitability to the climate and soil and to the purpose for which it is grown. Different grasses make different demands. All of course require sufficient food and water, but what is enough for one may bring another to the point of starvation. A water supply which produces luxuriant growth in a certain grass may prove injurious to another, perhaps closely related, species. Thus Sheep's Fescue can make a comfortable living where Meadow Fescue would suffer seriously. On the other hand, Meadow Fescue and Orchard Grass would languish in wet and sour soil, where Blue-joint Grass, Meadow Foxtail and Fowl Meadow Grass would grow luxuriantly. It is therefore important to choose varieties to suit the locality.
Such grasses as Red Top, which have a creeping root system and grow from early spring to late fall if the weather is favourable, are especially fitted for pasture, as they stand tramping and provide green food the whole season. On the other hand, they are not good for hay, as most of the leaves are rather close to the ground. Timothy and similar grasses are less adapted for pasturing, as their bunchy growth and shallow root system make them liable to be uprooted or at least injured by tramping. But this type of grass furnishes excellent hay.
The development and duration of a grass are also factors to be considered. Some start growth very early in spring, and are valuable when early hay or pasture is required. Others, starting late, are rather slow and are desirable for late hay or pasture. Some grasses are short-lived and die after the first or second year; Italian Rye, for instance, may be used in a short rotation, but is of no use for permanent pasture. Most of the perennial grasses reach full development the second or third year after sowing, and are valuable when permanent pasture or hay is desired.
One variety is rarely grown alone, except when intended for seed, as mixtures of grasses or grasses and clovers generally give a higher yield of better quality. Orchard Grass, for instance, is generally grown with other varieties. If grown alone, it would be coarser, less digestible and less palatable. The farmer's demand for the maximum yield of the best obtainable quality has led to the use of mixtures which give the heaviest possible returns in hay or pasture of the highest feeding value.
To obtain a heavy yield it is not sufficient to choose grasses which are heavy producers when grown alone. They must be adapted to the soil and climate and be able to thrive together and make the best possible use of every inch of ground. When hay is desired, the worth of the mixture depends not only on the value of the individual grasses, but also on their ripening together. An ideal mixture is composed of species which reach the flowering stage at the same time. The proper time to cut for hay is generally during early flowering. If very early and very late grasses are grown together, the return will be comparatively small and the quality of the hay inferior. Which species should be used depends upon the soil, rainfall, and other factors.
Clovers are often grown with grasses because such a mixture gives a better balanced feed and does not rob the soil of as much fertility as would grasses alone, which are heavy feeders. A ton of Timothy hay contains about eighteen pounds of nitrogen, six and one-half pounds of phosphoric acid and from twenty-eight to thirty pounds of potash. This is rather more than would be returned to the land by a ton of ordinary green farmyard manure. If no fertilizers are applied, it is evident that continuous crops of Timothy would rapidly deplete the soil, and the same is true, in a general way, of other grasses. Leguminous plants (see page 18) accumulate nitrogen from the air and are of great importance as soil improvers. Clovers return nitrogen to the soil, and thus to a certain degree maintain its fertility.