BOTANY. That branch of biology, or the science of living organisms, which deals with plants, and is thus distinguished from zoology, which deals with animals. An individual plant, considered as a living or once living organism, may be studied in two ways—with reference to its structure or with reference to its functions. These represent the two great subdivisions of pure botanical science—anatomy and physiology respectively. All other phases of botanical sci ence are special developments of one of these two, either alone or in combination with the other, or in relation additionally to some other branch of knowledge. Anatomy and physiology are thus the primary elements, as it were, of botany, which in varying combinations with each other and with the elements of other sciences constitute the branches of botanical science actually in existence, such as taxonomy, ecology, cytology and pathology. The term plant anat omy is restricted frequently in actual use to gross anatomy and is often called structural bot any. In this sense is covered about as much of the whole of anatomy as can be studied by the unaided eye or with a lens. Minute anatomy, or histology, covers the minute structure of plants, the principal instrument in its study. being the compound microscope. A study of the rela tionships of plants on the basis of anatomical re semblances constitutes comparative anatomy, or morphology. The classification of plants, known as taxonomy or systematic botany, is in the main a specialized branch of morphology, for the principal means by which plants may be grouped so as to indicate their genetic relationship is a comparison of their structural differences and resemblances. In its actual study plant physi ology is closely associated with plant histology because most of the functions of the plant are intimately connected with the structure of plant cells, and the physiologist must of necessity understand these structures. A special branch of botanical research which has to do with the complex structure and activities of the plant cell is known as plant cytology. The study of the diseases of plants, whether they are due to fungi or other plant organisms, or are purely physiological, is plant pathology, sometimes called vegetable pathology.
History.— Among the ancients, Aristotle, the Greek philosopher (384 to 322 a.c.), The ophrastus, his pupil (about 372 to 287 a.c.), the Roman naturalist, Pliny the Elder (23 to 79 Am.), and the Greek physician, Dioscorides (of the 1st or 2d century A.D.), left botanical records of historical interest, but botany as a modern science has developed in the last four centuries, dating from the Reformation. The writing, par ticularly by the Germans, of herbals, or treat ises on economic and medicinal plants, and the founding of botanical gardens, occupied most of the 16th century, but in the year 1583 Cesal pino, an Italian physician, published the first formal and comprehensive classification of plants. This, though artificial, formed the basis of all generally recognized classification to and including the time of Linnaeus in the latter part of the 18th century. The 17th century was
chiefly notable for advances not in the classifi cation of plants, but in their structure and vital processes. Malpighi, an Italian, and Grew, an Englishman, almost simultaneously published their researches on the gross anatomy and the cellular structure of plants, the first of which were presented in 1671. To the work of these men in plant anatomy little of importance was added in more than a hundred years. The other important discovery of the century was the demonstration by Camerarius in 1691, through direct experiment, of the sexuality of plants. The 18th century was marked especially by advances in classification. In the year 1700 Tournefort published his 'Institutiones,' in which for the first time genera were systematic ally named and described. During this century Linnaeus, the great botanical compiler and sys tematizer, brought out his successive works, cul minating in the (Species Plantarum,> in 1753. It was later in the same century, too, that bo tanical exploration came to be recognized as an important department of the voyages of geo graphic and scientific discovery in which the nations of Europe became engaged. In 1789 A. L. de Jussieu published his 'Genera Plantarum,> in which was first systematically formulated a comprehensive classification of plants according to their natural relationship, as opposed to the artificial systems followed by Cesalpino and Linnaeus. In the last two decades of this cen tury were laid the foundations of our present knowledge of the important part played by the air in the nutrition of plants, a proper concep tion of which was possible only in the light of the new developments which took place at that time in chemistry. The 19th century witnessed enormous strides in plant anatomy and plant physiology, the latter largely contributed to by workers in chemistry and physics, and the former rendered possible by improvements of the compound microscope and accessory in struments, especially those which came into general use about 1840. From this movement has been derived most of our knowledge of the life-history and relationship of the lower groups of plants, the fungi, algae and lichens, and the assignment of the pines and their rela tives to their true position next above the ferns. The whole realm of botanical research was pro foundly affected by the work of Darwin, begin ning with the publication of his 'Descent of Man,> in 1858, which gave a new point of view for all subsequent work. In systematic botany the principle of the development of species from a common ancestor was substituted for the old view of the constancy of species. The remarkable adaptations for cross fertilization in the coloration, odor and structure of flowers was given its true and significant explanation as a means for originating and perpetuating species. Darwin's work gave a new philosophi cal basis for the interpretation of observed phe nomena and facts.