BOTANY 145 



each fermentable substance is only affected by its own particular enzyme this does not 

 settle the question as to whether these bodies may not be resolved into fewer substances 

 each more or less protean in form. For it appears to be tolerably certain that enzyme- 

 action in general is a function of the surface properties of the . substances which are 

 responsible for its occurrence. It may happen (and often does) that the enzyme is 

 located in more or less specialised cells adjacent to, but not identical with, those which 

 contain the fermentable material, and in some seeds and fruits the two classes of sub- 

 stance may eyen be contained in quite different tissue systems.' H. E. Armstrong's 

 investigations also show that there may exist a considerable range of variation in. the 

 accompaniment of enzyme and glucoside in nearly related varieties and species of plants. 

 The glucoside may be very scarce, with a minimal quantity of .the enzyme, or while the 

 latter may be abundant the glucoside may be lacking. The suggestive bearing of such 

 observations on the chemical differences between species is obvious, and the -matter has 

 already been referred to in connection with the colour inheritance of plants of hybrid 

 origin. 



An excellent resume of the physico-chemical aspect of plant physiology, and especially of 

 respiration in its relation to fermentation, is given in Palladin's Pflanzenphysiologie, Berlin, 

 1911, also Jost, Vorlesungen u. Pflanzenphysiologie, 2te aufl.; H. E. & E. F. Armstrong, 

 series of investigations on ferments in recent vols. of the Proc. Roy. Soc.;. F. Blackman, 

 numerous papers in the Phil. Trans. Roy. Soc. dealing especially with photosynthesis, and 

 articles in recent .volumes of New Phytologist; F. Czapek, Ueber eine methode zur direkten 

 Bestimmung der Oberflachenspannung der Plasmahaut von Pflanzenzellen, Jena, 1911, and 

 Chemical Phenomena in Life, London, 191 1 ; W. W. Lepeschkin, u Ueber die einWirkung anaes- 

 thesirende Stoffe auf d. Osmo. Eigenschaften d. Plasmamembran," Ber. Deut. Bot. Gesellsch., 

 Bd. 29, 1911. 



Angiosperms. Although the past few years have produced no very startling changes 

 in the views entertained as regards the phylogeny and interrelations of the angiosperms, 

 several important works have appeared which continue to voice the divergent opinions 

 entertained on these questions. The point of view adopted depends largely on the/value 

 placed on different criteria. Thus whilst Wettstein regards the Monocotyledons as 

 having arisen from Dicotyledons via the Ranales and Helobiae, Lotsy in his large work, 

 still in course of publication, while admitting the probability of this view for one group of 

 Monocotyledons, considers the whole class as at any rate diphyletic. He sees a second 

 point of contact, through the aroids, with the Dicotyledonous piperales. In this he is 

 supported by some American writers who have approached the matter from another, 

 the embryological, side. Lotsy goes further than many systematists will follow him in 

 deriving the Dicotyledons, through the magnolia-like forms, from the fossil gymnosperm 

 type of Bennettites. Most authorities are inclined to look with scepticism on a supposed 

 origin of the angiosperms from any gymnospermic ancestors at present known to us, and 

 the recent discoveries of angiospermic remains of a highly organised type in the Lower 

 Cretaceous rocks adds weight to the negative position. For the plain indication is that 

 the angiosperms were already a flourishing family even at the time when the Bennetti- 

 teae were in their prime, whilst evidence from other sides points to the conclusion that 

 the importance of this group of fossils may easily be overestimated in framing large 

 phylogenetic schemes. 



j Gymnosperms. Considerable attention has been focussed upon the gymnosperm 

 ever since the discovery of motile antherozoids, first in Ginkgo and subsequently in the 

 Cycads. The study of the fossil seeds, and of the Bennettitian remains in America 

 have further added to and consolidated our knowledge of a group which is now perhaps 

 better understood than most of the other important sections of the vegetable, kingdom. 

 A very large share in the elucidation of the structure and development of individual liv- 

 ing species has been undertaken by American botanists. The results of modern investi- 

 gations have been well brought together by Coulter and Chamberlain in their recent 

 volume on the gymnosperms. Still more recently, the thorough study of the morphology 

 of the Podocarpoid alliance has cleared up much that was obscure in this important 

 group of genera, and has thrown light on their relationship with the cone bearing species 

 of gymnosperms. 



