NOTES AND ABSTRACTS. 



397 



and stem turn black, and look as if they had been cut by frost, and 

 the fruit turns black at the stem end. The plant succumbs rapidly, 

 and white tufts of conidiophores appear on the under surface of the 

 leaves, on the stem, and in the furrow round the fruit stalk. Unless 

 associated with other organisms the Phytophthora does not produce 

 wet rot in the fruit. 



The above diseases are controlled by spraying with Bordeaux and 

 lime-sulphur washes. — D. M. C. 



Transpiration and Light Intensity. By B. E. Livingstone 

 {Bot. Gaz. pp. 417-438, Dec. 1911; 1 fig.).— In order to test the 

 various methods of recording transpiration, the author compared the 

 actual amount of water transpired (under given light conditions) by 

 three plants — Physalis, Xanthium, and Martynia — with the results as 

 shown by Hicks' solar radio-integrator, three porous cup atmometers 

 (brown, white, and black), a black bulb thermometer in vacuo (Kny 

 Scheerer), Wynne's exposure meter with standardized paper, and 

 Clements' actinometer with solio paper. 



Graphs are given showing the records obtained by these various 

 instruments, and by the living plants under same conditions' of exposure; 

 coefficients of correction, are also calculated. 



The author concludes that, on the whole, the black and brown 

 atmometers and the Hicks' integrator are valuable instruments for 

 estimating solar intensity so far as transpiration is concerned. The 

 black bulb thermometer recommends itself as the best of the non- 

 integrating devices. The photographic papers may be valuable when 

 the effects of light variations on photo-synthesis, rather than on trans= 

 piration, are to be determined. — G. F. S. E. 



Transpiration, Variations in. By B. E. Livingstone and W. H. 

 Brown {Bot. Gaz. pp. 309-330, April 1912).— The authors collected 



I once every hour or every two hours a large number of similar leaves 

 from plants growing in the open. These were immediately placed in 

 stoppered bottles, and the moisture contents calculated by the dry 



' weight obtained. 



. The authors found, at least frequently, a marked decrease of 

 j moisture in the leaf during the day, and a corresponding rise at night. 

 I Some non-succulent, small-leaved desert plants and some succulents 

 do not show the same diurnal fall. — G. F. S. E. 



Trees, Effect of Drought on. By Huebner (Garten flora, 

 vol. Ixi. pt. iv. pp. 76-82). — In the district of Teltow the drought of 

 1911 had a disastrous effect on the Birch, Elm, Juniper, Lime, Picea 

 '■■ excelsa, Ahies yectinata, Taxus haccata, and Thuya occidentale. The 

 j Canadian Poplar resisted the drought better than the black and white 

 I Poplars. The dry season suited the Tamarisks, Buddleia, Exochorda, 

 Hijdrangea, and Ligustrum. Green Fly did much damage, but fungoid 

 I diseases were less prevalent than usual.— 5'. E. W. 



