PLANTS AND ANIMALS COMPRISE THE PRODUCTS OF AGRICULTURE. The plants make it possible for the animals to live. The purpose of this volume is to discuss the plant products of the farm ; and the first general subject that may receive attention is a discussion of the plant in its physio logical relations with its environment and with various practices of the cultivator.
In its broadest application, agriculture is concerned with all plants that are grown by man, whether for his own direct use in food and clothing and shelter, or for his animals, or for the gratification of his msthetic tastes. The kinds of plants that are grown for his own sustenance and protection and for his animals are comparatively few, and they are the ones intended in this Cyclopedia. The number that are grown to satisfy his artistic tastes are legion and they cannot be enumerated here ; these are recorded, for this country, in the Editor's Cyclopedia of American Horticulture. All so-called horticultural plants and crops, whether for food or ornament, are included in that work, and therefore the fruits and vegetables are given only short and summary treatment in the present vol ume; and for the same reason, discussions of horticultural practices are omitted here.
The vegetable kingdom is of marvelous diversity. Any observing person has only to recall the range of his own observation to illustrate how true this is. From trees to water-plants and ferns and mushrooms and sea-weeds is a far sweep of organic forms. A glance at the contrasts of Figs. 1 to 3 enforce this range of the vegetable kingdom. Some of its members, as the bacteria, are even microscopic and not attached to the earth or other support. Some of these minute forms have the power of moving in their liquid habitation. The bacteria subsist on food organ ized by other plants or by animals, sometimes existing on the living body, when they are said to be parasitic, sometimes on disorganizing or decaying matter, when they are said to be saprophytic. Some plants, of larger size and more complex structure, become individu ally attached to a host plant, practically taking root thereon, as the mistletoe. Such plants may have foliage or green leaves, or they may be blanched and unable to organize food for themselves. The
mushrooms and toadstools, representing the so-called higher fungi, are saprophytic on decaying matter in the ground or in old logs and litter. Most plants, however, are earth-parasites, fixed in the soil, drawing their food from it and supplementing this supply from the carbon of the air. Plants have become adapted to all places on the earth where life is possible, modified in duration, form, stature and physiological action. They have also become adapted to the struggle for existence with each other, contending for space and light. Some are creepers on the ground ; others climbers on rocks and on their fellows ; others tower above all competitors. Some are adapted to shady places. Some inhabit the water ; others have escaped to the marshes, the plains and the hills. In the long pro cesses of time, one kind has given rise to other kinds. Some forms have died and are lost. The plant creation is plastic, abounding and living. This creation stands batween man and the soil of the earth.
The most marked division line in the vegetable kingdom is between the flowerless plants and the flowering plants. the former including all bacteria, yeasts, fungi, algae (to which the sea-weeds belong), liverworts, lichens, mosses, ferns. The demarcation between these two groups is not so marked morpho logically as it was once supposed to be, and the present tendency is to drop the distinction as respects flowerless or flowering feature, and to speak of one group as spore-bearing and the other as seed 'waring : even this distinction is not wholly true, but the morphological phase of the subject does not need consideration here, and the two groups, being natural, may be maintained even if the terminology is ansatisfactory. The seed-bearers naturally divide into the gymnosperms, in which the ovules are naked (not inclosed in an ovary or pericarp), and the angiosperms, or ovary-bearing plants. The former include the pines, spruces, firs, larches, cedars, yews, and some other woody plants. Geologically, the group is old. The angiosperms comprise all the remainder of the flowering plants, making up by far the larger part of the conspicuous flora of the earth.