830 REPORT— 1901. 



persistent calyx as in Latiatse, or within bracts as in Graminese. This feature, it 

 will be observed, emphasises that which I have put in the forefront, as leading to 

 the establishment of the angiospermous type. That it must give greater seciu-ity 

 to the embryo in relation to its water-supply is obvious, although it has evidently 

 also direct connection with seed-dispersal. Another general character observed in 

 these higher groups is the greater security for economical pollination afibrded by 

 the adaptations in relation to insect-visits. At the same time the case of the 

 Gramineffi shows us that other adaptations in this respect are not incompatible 

 with prominence. 



I will not dwell upon the influence of water upon the vegetative organs in 

 Dicotyledones and Monocotyledones. Of all the factors of environment its effects 

 are best known because most easily seen. The examination of plants from the 

 standpoint of their relation to water — bearing in mind that this is physiological, 

 and not merely physical — has already thrown a flood of hght upon their forms and 

 upon their distribution, and offers a fertile field of investigation for the future. 



Water has been, then, a dominating influence at all periods in the evolution of 

 our vegetation. The picture of its claim in this respect which I have presented to 

 you is drawn in the broadest outline, and with the intention more of recalling 

 points of view from which familiar facts in the life of plants may be looked at. 

 It is just occasions like this which give the opportunity of telling to a competent 

 audience of the impressions received by one's most recent glimpse in the 

 kaleidoscope of plant-life. It is in this spirit I ofter my imperfect sketch. 



The following Papers and Eeports were read : — 



1. Tltp International Association of Botanists. By Dr. J. P. Lotsy. 



2. Cytology oj the Cyanophycece. By Harold Wager. 



The researches of Scott, Zacharias, and others have definitely revealed the fact 

 that the contents of the cells of the CyanophycefB are differentiated into two dis- 

 tinct portions, an outer peripheral layer in which the colouring matters are placed 

 and a central colourless portion which is usually spoken of as the ' central body.' 

 The central body is regarded by many observers, and notably by Biitschli, as a 

 true nucleus. So far as my own observations go, it appears to me to resemble the 

 nuclei of higher organisms in that it is composed of a chromatic network, but 

 differs from them in the absence of a nuclear membrane and nucleolus. Staining 

 and other reactions show that chromatin is present, but in most cases only in 

 small quantities. The presence of phosphorus in the central body can also be 

 demonstrated, as Macallum has shown, by means of the molybdate, phenjd- 

 lij'drazin reaction. 



In the process of division the cell begins to divide and new cell walls formed 

 independently of the division of the nucleus. 



In the process of nuclear division the chromatin threads become drawn out 

 longitudinally and parallel to one another, and are then divided transversely. 

 Some of the division stages, especially in elongate cells, resemble stages in true 

 karyokinetic division. 



Various staining methods can be employed to render the structure of the 

 central body visible, but it is more clearly demonstrated in some species than 

 others. 



The colouring matter is not distributed evenly through the peripheral layer. 

 It occurs in the form of granules or fibrils. The structure of the peripheral layer 

 recalls that of the chromatophores found in other organisms. It consists of a 

 colourless and a coloured portion, and the coloured portion appears, as before men- 

 tioned, fibrillar or granular. 



The investigation of the cell structure of the Cyanophycece is not interfered 

 with to any considerable extent by plasmolysis phenomena. 



