86 Physiologie. 



are tested with Guignard's alkaline picrate paper some plants 

 gave evidence of the presence of hydrogen Cyanide, vvhile others 

 gave no reaction. 



The results of two years' experiments lead to the correlation of 

 the appearance of the cyanophoric glucoside and the attendant en- 

 zyme with climatic conditions which favour maturity rather than 

 luxuriance of growth. The investigations have been extended to 

 plants from all parts of Europe with similar results. The plant is 

 evidently variable, and cyanophoric and acyanophoric plants may 

 occur in close proxirait3^ Attempts have been made to isolate the 

 glucoside but with no success so far. Other experiments were made 

 to determine the enzymic activity of the plant, the results being 

 given in a table. 



Hydrogen Cyanide has also been detected in some other species 

 of Lotus, but no trace of it has been proved in Hippocrepis comosa, 

 a. plant which resembles Lotus corniculatus very closely. 



W. E. Brenchley. 



Brenchley, W. E., The Development of the Grain of 

 Barley. (Ann. Bot. 26. NO 103. p. 903-928. July 1912.) 



Samples of Barley plants and grain were taken at three-day 

 intervals from the time of flowering until harvest. Various chemical 

 analyses were made on the straw and grain, the results being cor- 

 related and expressed in the form of curves. A comparison is 

 drawn between the composition of the grain and the whole plant of 

 barley and whsat at progressive stages of growth. The progress of 

 the entry of starch into the grain is traced and also the disorgani- 

 sation of the nuclei that occurs during development. 



The results may be summarised thus: 1. The weight of the 

 whole plant, the nitrogen, ash and phosphoric acid increase stea- 

 dily until a maximum is reached by the time dessication sets in. 

 Then while the nitrogen and phosphoric acid remain fairly constant. 

 the weights of the whole plants and the ash decrease. 



2. Certain maturation changes are evident during the prolonged 

 dessication period of barley, with are scarcely seen in wheat. 



3. With wheat the manuring hardly aflfects the analyses of 

 grain or straw, but in Barley the effect of Phoshoric acid starva- 

 tion is reflected in the results obtained. 



4. Starch infiltration foUows a progressive course from the cha- 

 lazal end of the grain up towards the embryo. The nuclei of the 

 cells undergo a gradual deformation into networks, probabh^ owing 

 to the increasing pressure of the starch grains. 



W. E. Brenchley. 



Groom, P., Some Aspects of Periodicity in Plants. (Science 

 Progress VI. p. 62. 1911.) 



After a general introduction, longevity of individual plants and 

 of seeds is dealt with, and the question of times of flowering in 

 different species is discussed. Other subjects treated are the rh3'^thmic 

 change of form illustrated by the successional change in the 

 dimensions of the leaves and internodes of a shoot produced during 

 one vegetative season, the formation of annual rings, etc. 



Agnes Arber (Cambridge). 



