286 Forestry Quarterly. 



rill. The perithecia were found December 30, 191 1 on diseased 

 and undersized oak leaves on an unthrifty trunk of Quercus sessil- 

 iflora in southern France. Harlot and Mangin had earlier pre- 

 dicted this connection, but had no direct evidence. Several 

 authors have attempted to show a difference in form between the 

 conidia of the "oak-mildew" and those of AL alni, and Griffon 

 and Maublanc finally ventured to describe the fungus as O'idium 

 alphitoides. 



The present authors compared their material with specimens of 

 M. alni on leaves of several North American oaks supplied by 

 Professor Farlow of Harvard University, and were unable to 

 establish specific differences which would warrant a separation. 

 A description of the French collection is given. The conidia are 

 shown to be quite variable, and this has, in the opinion of the 

 authors, led several investigators to make distinctions which are 

 not justifiable. 



The authors believe that the fungus is indigenous, and not in- 

 troduced from America, and express the view that, at first, it was 

 localized, or rare, and has developed rapidly under the influence 

 of slight modifications in the host which were favorable to its 

 evolution. The present appearance of the perithecia is attributed 

 to the dry summer of iQii, followed by a wet mild autumn which 

 gave a long growing period. 



Sur la forme de I'Oidium du chine en France. Comptes Rendues 

 Academic Science (Paris), January, 1912. 154:124-127, 15. 



SOIL, WATER AND CLIMATE. 



Dr. Leininger of Tharandt points out that 



Site the description of sites and their classifi- 



Classification. cations by estimate, as usually practised, 



especially for experimental work, is en- 

 tirely inadequate, because the estimate is made without any mea- 

 sured basis. He quotes the best authorities, referring to the 

 absolute ignorance mostly exhibited in this direction, and cites the 

 work of Braza who examined the site description based on opinion 

 in the yield tables of Weise for pine in detail of mineral constitu- 

 ents, humus contents, soil moisture and compactness, and found 

 no proportional relations between those factors and the site 

 classification. 



