The maxims however of Ray, and the great general views of that illustrious naturalist, were destined not to fade even before the meteoric brilliancy that surrounded the throne of Linnaeus. A French botanist, Antoine Laurent de Jussieu, soon entered the field to oppose the latter. In the year 1789, just eleven years after the death of Liu mous, be produced under the name of Genera Plantarum' an arrange ment of plants according to their natural relations, in which the principles of the great English botanist are tacitly admitted, and his fundamental divisions adopted, in combination, in part with those of Tournefort, in part with those which bad been proposed by Adansdn in his remarkable work on the Families des Plantes,' and the rest with what are peculiar to the author himself. Jussieu possessed in a happier degree than any man that has succeeded him the art of adapting the simplicity and accuracy of the language of Linnaeus to the exigencies of science, without encumbering himself with its pedantry. He knew the impossibility of employing any single charac ters to distinguish objects so variable in their nature as plants ; and he clearly saw to what evils all artificial systems must of necessity give rise. Without pretending then to the conciseness of Linnaeus in forming his generic characters, he rendered them as brief as was con sistent with clearness ; without peremptorily excluding all distinctions not derived from the fructification, he nevertheless made the latter the essential consideration ; instead of defining his classes and orders by a few artificial marks, he formed them from a view of all the most essential parts of structure ; and thus he collected under the same divisions all those plants which are most nearly allied to each other. Hence, while a knowledge of one plant does not by any means lead to that of another in the system of Linnaeus, it leads directly to tho knowledge of many more in the classification of Jussieu, which has accordingly gained the name of the 'Natural System.? This at once brought the science back to a healthy state ; it demonstrated the pos sibilty of reducing the characters of natural groups to words, contrary to the opinion of Limucus, who found that task altogether beyond his powers ; it did away with the necessity of artificial arrangements, and, giving a death-blow to verbal botany, it laid the foundation of that beautiful but still imperfect superstructure which has been erected by the labours of Brown, De Candolle, Lindley, and others. If tho system of Jussieu were not a return to that of Ray, modified only and improved by modern discoveries, we should certainly have taken this period for the commencement of The Sixth and latest Era in our science. But it was reserved for a man whose fame lies chiefly in the literary world to effect the last great revolution that the ideas of botanists have undergone. In 1790, one year after the appearance of Jussieu's Genera Plantarum,' the German poet Gothe published a pamphlet called The Metamorphosis of Plants.' At that time the various organs of which plants consist had been pretty well ascertained, the distinctions between the leaf, the calyx, the corolla, the stamens, and the pistil were in a great measure understood, and the botanists were not a few who fancied there was nothing more to learn about them. Nevertheless even in the time of Theophrastus a notion had existed that certain forms of leaves were mere modifications of others that appeared very different, as the angular leaves in croton of the round cotyledons or seminal leaves of that plant. Linnaeus himself had entertained the opinion that all the parts of a flower are mere modifications of leaves whose period of development is anticipated (' Prolepsis Plantarum'); Ludwig in 1757, and more especially Wolff in 1768, had stated in express terms that all the organs of plants are reducible to the axis and its appendages, of the latter of which the leaf is to be taken as the uni versal type. But the theory of Linnaeus was fanciful ; Ludwig was a
writer of too little authority in his day to succeed in establishing a doctrine so much at variance with received opinions; and the theory of Wolff was propounded in a paper upon the formation of the intes tines in animals, which seems altogether to have escaped the observa tion of botanists. Entirely unacquainted with the writings of the two latter naturalists, but aware of the Prelepsis Plantarum' of Linnaeus, Gethe took up this important theory, and demonstrated that all those organs to which so many different names were applied, and which in fact have so many dissimilar functions to perform, Were all modifica tions of one common type—tho leaf; that the bract is a contracted leaf, the calyx a combination of several, the corolla a union of several more in a coloured state, the stamens contracted and coloured loaves with their parenchyma in a state of disiutegmtion, and the pistil another arrangement of leaves rolled up and combined according to certain invariable laws.
Although at first Guthe's views were disregarded, they were gradu ally adopted, and formed the basis of inquiries in that department of botany called the Morphology of Plants. To no one is the science of Botany more indebted, from his early adoption of the generalisation of G5the, then Robert Brown. In his ' Prodrornua of the Flora of New Jlolkuul,' and in a multitude of papers in the Philosophical' and ' Limeesn Transactions,' he proved not only the truth of Gotho's law but practically demonstrated its importance. It was never with him a theory, as it was with its discoverer, but a great generalisation which every now fact in the vegetable kingdom served to confirm. Nur did he apply it to the superficial facts of the structure of plants, but working with the microscope ho applied it to the development of the tissues of plants, and in every department of botany has made it to bear most abundant fruit. With the name of Brown in the modern history of botany we timid also associate the name of another English nuin—Dr. Lindley, who, by his extensive knowledge of vegetable structures, his indefatigable industry, and power of generalisation, has contributed very largely to the perfection of the present chussification of plants, as well as to the diffusion of sound general views on the subject of botany and its practical applications. To De Candollo also in recent times the progress of botany is deeply indebted, more espe cially for his laborious ' l'rodromue of the Vegetable Kingdom,' in which not only are the orders described, but the genera and species. We can only add that in recent times the science of Botany has been indebted to the labours of the following amongst other observers : Schleiden, Richard, Brogniart, Tulasne, Unger, Endlicher, Schacht, Von Mold, Bischoff, Treviranus, Lehmann, Suminaki, llofTmeister, Sir W. J. Hooker, J. D. Hooker, Henfrey, Bentham, Walker Arnott, Wright, Wallich. Boyle, Balfour, lkibington, Leighton, Biers, J. J. Bennett, T. Thomson, Asa Gray, Henslow, Berkeley.
In order to facilitate the study of Botany by the aid of this work, we give the following Glossary of the terms employed when describing the parts of plants.