CLASS BOOK OF BOTANY BEING AN INTRODUCTION TO THE STUDY OF THE VEGETABLE KINGDOM. BY J. H. BALFOUR, M.D., F.R.S. E., REGIUS KEEPER OF THE ROYAL BOTANIC GARDEN, PROFESSOR OF MEDICINE AND BOTANY IN THE UNIVERSITY OF EDINBURGH, WITH UPWARDS OF 1000 ILLUSTRATIONS. EDINBURGH: ADAM AND CHARLES BLACK, NORTH BRIDGE. LONGMAN & CO. LONDON. MDCCCLII. PREFACE. THE object of the present work is to initiate the student into the study of the structure and forms of the various parts of plants. It embraces what is commonly called Vegetable Organography, or a description of the tissues of which plants are composed, and of the various organs which are concerned in the processes of nutrition and reproduction. Without an accurate knowledge of this department of Botany, it is impossible to make progress either in the physiology or in the classification of plants. It bears to Botany the same relation that anatomy does to practical medicine. It is the basis and foundation on which the superstructure is to be raised. In the following pages, plants are in the first instance considered with reference to their minute structure. This is the Histological division of the subject, and calls for the use of the microscope. The combinations of the elementary tissues, which constitute the different organs, are next brought under consideration, and the plant is traced from its simplest condition through various morphological changes until it acquires the complete form of the seed-bearing individual. The laws of Morphology, or of the transformations of organs, and the general principles of Vegetable Symmetry, are also brought under the notice of the student. As flowering and flowerless plants differ essentially in their reproductive organs, it has been thought proper to treat |