“Very clear, indeed,” said Miss Perceval, “and quite full enough. The grasses are easily distinguishable from all other plants, except the Cyperacea; and even they shew a well-marked line of separation, as their stems are sometimes triangular, and very seldom jointed; and the sheath is always entire, not split like that of the grasses.
“The grasses are of the greatest importance,” she continued, “in the economy of nature; they form in most countries the chief covering of the earth; they are the principal support of terrestrial animals; and you know that the basis of all agriculture is the cultivation of plants which belong to their order.”
Miss P. easily allows herself to be drawn out, and before we reached home, we obtained the following particulars of that numerous family.
“There are about eighteen hundred species already known; and the industry of botanists is every day adding to the list: there are both land and fresh-water grasses, but no marine grass. They occur in every soil; generally in society with other grasses, but sometimes a single species will be found occupying a considerable district. Sand appears the least favourable to their growth; but even sand has species peculiar to itself. They are spread over the whole vegetable kingdom, from the equator to the polar regions; and from the sea-shores to the tops of the highest mountains, at least to the line of perpetual congelation.
“We are still in want of a perfect natural classification, by which their distribution on the globe might be made more distinct: at present, each of the ten groups into which they are arranged, contains too many, so that not one of the groups belongs exclusively to any one zone. Some, however, may be regarded as tropical, and some as chiefly inhabiting the temperate climates. The variation of the grasses in the different continents is still less perceptible; there is scarcely any difference between those of North America and those of the temperate regions of the European continent. Between the two temperate zones also the distinction is inconsiderable. Of thirty-six species from the Cape, thirty occur in the northern hemisphere; while in other tribes of plants, Southern Africa has many that are peculiar to itself. I may mention poa as being one of the most extensively distributed genera; some of its species are found in every part of the world, from Spitsbergen to New Holland.”
“We may say then,” said Mary, “that latitude has but little influence on these plants.”
“Yes, it has a decided influence,” said Miss Perceval, “on their vegetation; the tropical grasses acquire a much greater height, and almost assume the appearance of trees. Some species of the bamboo, which you know belongs to this tribe, are fifty feet high. The leaves too are broader, and approach more in form to the leaves of the other families of plants.”
I then asked Miss P. to give me some idea of the distribution of those grasses which are cultivated.
“The cultivated grasses,” she said, “which extend farthest to the north in Europe, are barley and oats. These, which in milder climates are not generally used for bread, afford the inhabitants of Norway, Sweden, and Scotland, their chief vegetable nourishment. Rye comes next to these; it is the prevailing grain along the borders of the Baltic, and in part of Siberia. Next follows a zone including Europe and a large part of Western Asia, where rye disappears, and wheat almost exclusively furnishes bread.
“The next district extends across Barbary, Egypt, Persia, and the countries of the East, where, though wheat abounds, rice and maize are extensively cultivated; and in some of those countries the sorghum, which yields a grain resembling millet, and the poa Abyssinica, are largely used by the inhabitants. In the eastern parts of the temperate zone, including China and Japan, rice predominates over all other grains. Between the tropics, maize prevails in America, rice in Asia, and both in nearly equal quantities in Africa; probably because Asia is the native country of rice, and America of maize. The native country of wheat has not yet been ascertained, but there are few places into which it has not been introduced. Several other grains and plants that supply food, are cultivated in the torrid zone, but we cannot touch on them now, as they are not grasses.