THE PLIOCENE FLORAS OF THE DUTCH-PRUSSIAN BORDER 149 



belonging to families no longer found in Europe. Similarly a 

 cone referred to Sequoia is about 2 mm. long, though in the form 

 of the cone-scales it bears a close resemblance to the recent 

 species, and the genus is known to have flourished in England in 

 the Oiigocene period. A new genus of Anonaceae named 

 Jong7nansia, after Dr. W. J. Jongmans, is founded on seeds from 

 Eeuver and Swalmen. It is impossible to do justice to the 

 admirable work of Mr. and Mrs. Eeid within the limits of a 

 review ; it is a model of careful research and an exceptionally 

 important contribution towards the solution of phytogeographical 

 Pi'o^^lems. A. C. Seward. 



Tlie Princiijles of Plant -Teratology. By W. C. Worsdell. 8vo, 

 vol. i, pp. xxiv, 270, with 25 plates and 60 text-figs. 

 London : Kay Society, 1915. Price 25s. net. 



In 1869 the Eay Society issued Dr. Maxwell Masters's classic 

 w^ork on Vegetable Teratology. The method of arrangement 

 adopted was the obvious one, the author was treating of the 

 various abnormahties occurring in the plant-kingdom and bring- 

 ing together for the first time a great amount of detailed informa- 

 tion, and the type of abnormality therefore provided the basis for 

 the arrangement. Though the amount of knowledge on this 

 subject has increased greatly since Dr. Masters's book appeared, 

 an increase which was due in the first instance largely to his own 

 investigations, his Vegetable Teratology continues to be the most 

 ready book of reference, supplemented by Penzig's Pflanzen- 

 teratologie. Mr. Worsdell strikes a different note. His book "is 

 intended to present the subject in more scientific fashion, and in 

 quite a new form, both as regards the mode of treatment and the 

 large number of additional facts." The arrangement is a morpho- 

 logical one ; the subject matter, except in the small section on 

 Fungi, is treated under the headings of the various main organs 

 of the plant, root, stem, leaf, and flower. But the author has a 

 deeper purpose, to wit the study of the phylogenetic (evolutionary) 

 origin of the organs of plants. The chief problem to solve is : 

 from what original organ has this or that structure been derived 

 in the course of evolution, and what are the changes through 

 which it has passed in order to reach its present condition ? And 

 the best solution is reached, in Mr. Worsdell's opinion, by means 

 of the teratological method. The study of ontogeny is in some 

 cases a trustw^orthy guide, the anatomical method is of subsidiary 

 value for determining the morphological nature of an organ, the 

 comparative method is " pre-eminently serviceable," but " surely 

 most important and valuable of all is the teratological method." 



The author regards the vitalistic position as the only logical 

 one. Any change which takes place, whether normal or abnormal, 

 is always of the nature of a definite variation which under normal 

 conditions takes the form of a purposeful adaptation. Even in 

 cases where the change is harmful, as in double flowers, a 

 fasciated shoot or a virescent ovule, " there is in a sense a 

 purposive adaptation, for no doubt the plant adapts itself in the 

 best way it can to the abnormal conditions." 



