DIE VEGETATION DER ERDE. 371 classification. This is the fault not so much of Prof. Green as of the traditional system. Because the stodgy old type of Manual (to which Bentley's and Henfrey's belong) contained a condensed account of the characters of the groups and orders of plants, of very little service to anyone, Prof. Green has been at infinite pains to give us such accounts in which he exhibits the width of his reading and minute care in his selection of facts. It is good work thrown away for the greater part. Such details are right and proper in a special book on a particular group, but surely out of place in a general manual. From a book like Oliver's Lessons it is but a step to the use of a Flora such as Bentham's, and it is a pity to erect a barrier of such density between them. Prof. Green, we are confident, would never have invented such pemmican as he here offers for bread — it is an outcome of the miserable old tradition that Botany was to be taught in the most repellent way possible. We are sure he would never have invented it, because the physiology is treated in such a different way. By-the-bye, fig. 831 certainly does not represent the haustoria of the potato-disease fungus; and, speaking of figures, we note that many make two or more appear- ances in the course of the work. Turning from these complaints to meet Prof. Green on his own particular ground, the physiology of plants, it is difficult to avoid words of praise that will not be called extravagant. There is nothing so good, so shnple, and so valuable in every way in our language, and certainly no German could ever find it in his heart to write with such brevity and lucidity on plant physiology. So thoroughly good is it that we recommend the publishers to issue it separately as an Elementary Physiology. Where all deserves this praise, and all is so well sustained, it is difficult to point to any- thing of special merit; but Chapter V., which is introductory to the subject of the food of plants, is a capital example of clear writing and lucid exposition of a subject always difficult for the elementary student. Taking the Manual as a whole, it is an excellent investment for the university or college student. It is carefully and honestly done by a man of almost unique experience in the requirements and methods of our teaching establishments, and of excellent judgment as to what ought to be taught. _ G. M. Die Vegetation tier Erde. Sammlung pflanzengeographischer Mono- graphien, herausgegeben von A. Engler und 0. Drude. I. Grundziige der Pflanzenverbreitung auf der iberischen Halbinsel von Moritz Willkomm. 8vo, pp. xiv, 395, with 21 figures in the text, 2 photogravures, and 2 maps. Leipzig: Engelmann. 1896. Price 12 m. If corresponding areas of the earth were treated with the same exhaustiveness as has been the south-west peninsula of Europe by Moritz Willkomm, the series, of which the present is the opening volume, would be an extensive one. Such, however, is not the intention of the editors ; special attention will be given to the plant-
