Page:Collier's New Encyclopedia v. 02.djvu/148

BOSWELLIA Johnson, he carefully recorded his sayings, opinions, and actions, for future use in a biography. In 1773 he accompanied Johnson on a tour to the Scottish Highlands and the Hebrides, publishing an account of the excursion after their return. His “Life of Samuel Johnson,” one of the best pieces of biography in the language, was published in 1791. He died in London, May 19, 1795. His son,, born in 1775, created a Baronet in 1821, killed in a duel in 1822, excelled as a writer of Scotch humorous songs.  BOSWELLIA, named after Dr. John Boswell, of Edinburgh, Scotland. A fine genus of terebinthinous trees belonging to the order amyridaceæ (amyrids). B. thurifera, called also B. serrata, furnishes the resin called olibanum, which is believed to have been the frankincense of the ancients. It is found in India, as also is B. glabra, the resin of which is used instead of pitch. The products of the entire genus are more or less used in pharmacy.  BOSWORTH, or MARKET BOSWORTH, a small market town in Leicestershire, England, 12 miles W. by S. of Leicester. On a moor 2 miles to the S. was fought (1485) the battle in which Richard III. was slain, and which terminated the Wars of the Roses. On an elevation, called Crownhill, Lord Stanley placed the crown on the head of the Earl of Richmond, Henry VII.  BOTANY, the natural history of the vegetable kingdom, the science that treats of plants. It forms, with zoology, the subject of biology in its more comprehensive sense. Plants are living beings which derive their chief sustenance on the one hand from water, which, together with certain dissolved mineral substances, they take in through their roots from the soil, and on the other from carbonic acid gas, which they absorb through their leaves from the atmosphere. Plants alone are able thus to unite inorganic materials and create from them organic compounds capable of sustaining life. Plants thus have, in the economy of nature, the important function of forming from the crude substances of the mineral kingdom the elaborated food materials necessary, not only for their own vital energies, but for the direct or indirect support of all animal life as well. The process by which plants accomplish this chemical change is called assimilation and is carried on only through the agency of light and in the presence of their peculiar green pigment, known as leaf green or chlorophyll. The first product of the process (which is chemically one of deoxidation) is starch. Nitrogen, sodium, sulphur, and a few other elements are taken in by plants through their roots and in the form of dilute solutions. These elements combine with the starch derived by assimilation and form protoplasm and the other highly complex substances of the plant.

All plants, like animals, are composed of small bodies, which at least in their early stages, are microscopic masses of protoplasm, each provided with a specialized portion known as a nucleus. These bodies are called cells, although the name is inappropriate and founded upon the crude and mistaken ideas of the earliest microscopists. Plant cells differ from animal cells in the fact that they are not naked, but are each enveloped in a peculiar, usually transparent membrane of cellulose, a tough, elastic substance in composition allied to starch. In the simplest plants, it is often called protophytes. The cells are solitary, few, or, if more numerous, are essentially alike, being grouped usually in gelatinous masses. In the higher plants, however, the cells are always very numerous and many of them undergo great changes, some being transformed to tubes or vessels for the transmission of the sap, others being elongated and hardened into woody fibers, serve to give strength to the plant body, while still others, such as those of the outer layer (epidermis) assume a protective function.

Botany may be divided into three chief branches.

Structural Botany.—Structural botany includes all inquiries into the form, arrangement, internal anatomy, and composition of plants and their members.

Physiological Botany.—Physiological botany treats of the vital processes of the plant, both physical and chemical.

Systematic Botany.—Systematic botany deals with the different kinds of plants and groups them according to their racial affinities into orders, families, genera, species, varieties, and forms. Botanical histology is a term commonly applied to the minute anatomy or microscopic structure of the plants, especially of their tissues. Cytology deals with the physiology and histology of the individual cells. Vegetable pathology is a branch of physiology treating of plant diseases. Ecology comprehends a recently developed and highly interesting examination of the relations which exist between the structure of the plant and its environment. Economic botany treats of the