648 Physiologie. — Palaeontologie. — Algae. 



VI. Salt marsh Plants. In these plants the strength of sap may 

 reach the high value of 14958 mm. 



The conclusion drawn from the experimental work is as stated 

 below : 



The osmotic strength is least in submerged fresh water plants. 

 The greater the physiological drought under which the plants are 

 accustomed to grow the greater the strength of cell sap. In all 

 plants growing under the same conditions the strength of sap is 

 generally the same unless the anatomical arrangements for checking 

 loss of water by transpiration differ greatly. In that case the plant 

 with the less adequate anatomical provision has the greater strength 

 of cell sap. 



The direct effect on transpiration of increased osmotic strength 

 of sap will be negligible. The depression of the freezing point of 

 the sap within the ränge of strengths found will be small, but may 

 be of physiological value in plants with the greatest strength of sap. 



The effect of increased osmotic strength of sap on absorption 

 will be marked, and of considerable physiological importance. The 

 effect of increased temperature on any plant will be to increase the 

 osmotic pressure of the sap and thus to enhance the power of 

 absorption of water by the plant. E. Drabble (Liverpool). 



Ami, H. M., Notes on an Interesting Collection of Fossil 

 Fruits from Vermont, in the Museum of the Geological 

 Survey of Canada. (Ottawa Nat. XX. p. 15—17. 1906.) 



The specimens in this article were incorporated in the Museum 

 collection in the early days of Sir William Logan, having been 

 brought to notice by the eider Hitchcock in 1853 and first recorded 

 by him in the American Journal of Science for that year. Later, in 

 1905, Prof. G. H. Perkins, Director of the Geological Survey of 

 Vermont, studied this material and his results, as recorded in the 

 same Journal, were published in the Report of the Vermont State 

 Geologist for 1903-04. p. 174—212. D. P. Penhallow. 



Berry, E. W., Leaf Rafts and Fossil Leaves. (Torreya. VI. 

 12. p. 247—248. 1906.) 



The author directs attention to the waj^ in which leaf rafts are 

 formed in the rivers of the southern coastal piain of the United 

 States. As such rafts become stranded they sink to the bottom, be- 

 come covered with silt deposits and so pass into the condition of 

 fossil leaves. Comparison is made with deposits of Cretaceous and 

 Pleistocene leaves, and it is shown that the modern leaf rafts afford 

 a rational explanation of the circumstances under which at least 

 many of the earlier deposits of leaves were formed. 



D. P. Penhallow. 



Bradshaw, A. P., Short notes on the study of the British 

 Seaweeds. (Annual Report and Transactions of the Manchester 

 Microscopical Society for 1905. 1906. p. 56—60.) 



This paper consists of some populär remarks and notes on 

 marine algae, and is intended as a help to amateurs who niight take 



