748 Forestry Quarterly 



state of decay, and vesicles originating in the deep strata of the 

 cortical parenchyma were discovered. 



Character of mycelium and vesicles correspond exactly to those 

 of the endotrophic mycorrhizae of the olive — a weak parasitism 

 occiirring on a dying tissue. The one-year-old olive roots showed 

 no trace of the infection. 



The author concludes, that the failure of the olive trees in the 

 neighborhood of oaks is probably caused merely by the oaks having 

 impoverished the soil or by the eventual decay of the root due to 

 development of Dematrophora in the soil remains. "The theory 

 of any injurious action due to the mycelium of the diseased oak 

 roots may be totally discarded." 



Atti della Reale Academia dei Lincei, vol. xxiv, Rome, 1915, pp. 536-9. 



According to F. Doe, an excellent oppor- 



Asphyxiating tunity to study the effect of asphyxiating 



Gas gas on French forests is offered in the 



and Canton of Verzy, to the east of Rheims 



Vegetation and to the north of Chalons. According to 



Doe, the gas was launched October 19 and 



20, 1915. Blown by a high wind the heavy gas extended quickly 



over an area exceeding 10 miles from the place where it was 



started. The vineyards were not permanently injured, nor was 



cauliflower or turnips, but lettuce and most ornamental plants 



suffered severely. In the forests, the oak, beech, birch and 



hornbeam were not damaged, but the leaves of Scotch pine turned 



yellow, exactly as if the forest had been burned over. Apparently, 



the damage reported by Doe was very much the same as if there 



had been a large smelter in the neighborhood. 



T. S. W., Jr. 



Revue des Eaux et Forets, July 1, 1916, pp. 192-5. 



Continuing his discussion on the processes 

 Causes of diameter development (the first part 



oj briefed on pp. 325-7 of this volume), 



Tree Form Dr. Jaccard, of the Swiss Plant-Physio- 



logical Institute, discusses the physiological 

 reasons for winter rest. He refers to Klebs' experiments, who could 

 artificially produce in a given plant either continuous growth or 



