(From The London Gardeners' Magazine Of Botany.)

IN speaking of the age of trees, we insensibly use the term age, in the same manner as we do when speaking of animals. We talk of old trees, old animals, and old houses, as if the same processes had gone on in one as in the other. Yet, when we come to examine the nature of the changes which have taken place during the age of the one and the other, how different they are. Not more docs the process of change in the old house differ from the tree and animal, than does the same process in these two. The animal has but one life, and this life is dependent on the harmony of the whole organization; whilst, if we examine a tree, we shall find it has, (so to speak,) many lives. Each bud is capable of an independent existence; nay more, many parts of the tissues of plants are capable of producing buds, and each cell has its separate and independent existence. It is here, then, that we see how different must be the circumstances under which age is attained in a tree, from those which produce it in an

Plants are called annual, biennial, or perennial, as they endure for one, two, or more years. The difference depends on this, that the tissues of some plants arc unable to resist the meteorological iutiu-ences to which they are exposed, so well as others. The reason of this difference in the tissues is not well made out. It is, however, well known, that a plant in this country may be an annual, on the Continent, a biennial, and, in the Tropics, a shrub, or tree. This is the case with the castor-oil plant. Ricinus communis.