In several parts of England rye is sown either by itself, or mixed with tares to be cut whilst green, for the feeding of sheep, cows, and horses. Rye straw is used by brick-makers, and collar-manufacturers; and is considered an excellent material for the thatching of cottages and barns. 32. GRASSES.--_By grasses we are to understand such plants as have a round, jointed, and hollow stem, surrounded at each joint with a single leaf, long, narrow, and pointed; and the flowers of which are a kind of chaffy husk. According to this definition, wheat, barley, oats, and rye, properly belong to the grasses, although they are known by the peculiar appellation of corn or grain._[2] To the grasses it is that the face of nature is indebted for a great portion of its cheerful appearance, and its beauty. They constitute the general herbage of every country, covering to an immense extent the whole surface of the ground. They are very various in their kinds, the British species alone being nearly a hundred and twenty in number. To many species of animals their leaves afford an indispensable article of sustenance; and their seed supply food to birds. 33. _SWEET-SCENTED VERNAL GRASS_ (_Anthoxanthum odoratum_, Fig. 17).[3]--This species is usually considered (though it perhaps ought not exclusively to be so) as that to which the hay fields are indebted for their well-known and delightful fragrance. When partially dried it is very odorous; and, if chewed, in a recent state, its _stalks_ are highly aromatic, tasting not unlike those of fresh lavender. The _root_ has an odour somewhat resembling that of musk. A distilled water, which serves as a vehicle for some perfumes, is occasionally prepared from the leaves and flowers of the vernal grass. The dried flowers are employed in some parts of the Continent for imparting an agreeable flavour to snuff and tobacco. The vernal grass is not very productive, and by some farmers it is considered not palatable for cattle. Others, however, esteem it an useful addition in their meadows; and, from its being generally found in great abundance on such pastures as sheep are fond of, and afford excellent mutton, it is at least thought to be a good grass for them. 34. _COTTON GRASS_ (_Eriophorum angustifolium_, Fig. 18).--The seeds of this grass are encompassed with long cottony or wool-like hairs; and so abundant are the plants in many tracts of marshy land, particularly in the northern parts of England, that the ground appears almost as if covered with snow.