XXIII. Root of _Calamites_ (_Astromyelon Williamsonis_) in transverse section 254 XXIV. Cone of _Calamostachys Binneyana_; sporangia and sporangiophores 256 XXV. Harry Marshall Ward (1895) 261 XXVI. Sir Joseph Dalton Hooker (1868) 302 Text-fig. p. 77. Figure from _Vegetable Staticks_ showing a vine with mercury gauges in place to demonstrate root pressure. INTRODUCTION The present volume represents in somewhat expanded form a course of lectures arranged by the Board of Studies in Botany of the University of London and delivered during the early part of 1911 in the Botanical Department of University College, London. These lectures, which were ten in number, were widely attended by advanced and post-graduate students of the University and others interested in the subject. The ten lectures comprised in the course were delivered by various botanists, the lecturer in each case being either a worker in the same field as, or in some other way having a special qualification to deal with, his allotted subject. In view of the interest aroused by their delivery the hope found wide expression that the lectures might be issued in book form. At the time when the arrangements were being made for publication the University of London Press had not yet reached the publishing stage, so hospitality had to be sought elsewhere. That the book is issued from the Cambridge University Press is largely due to the good offices of Prof. A. C. Seward. In consenting to publish _The Makers of British Botany_ the Cambridge University Press suggested that some additional chapters should be prepared so that the work might be more fully representative. This has been done so far as was possible in the time available. The sixteen chapters forming the book include (1) the ten lectures, which are printed essentially as they were delivered, (2) six additional chapters specially written under the circumstances just mentioned. As a rule each chapter will be found to deal with a single Botanist; with the exception of the first and last chapters. In the former Prof. Vines has linked together Morison and Ray, the founders of Systematic Botany in this country, whilst in the last Prof. Bayley Balfour has expanded what was originally intended as a sketch of his father, the late Prof. J. Hutton Balfour, into a very interesting account of his predecessors in the Edinburgh chair from the year 1670 almost down to the present time. The subjects treated, the authors and the order of arrangement are as follows:--