Periodical Literature. 95 



progressing down the young lateral into the parent branch, 

 which, if strong, is not killed the first season. 



Remedial measures consist: (i) careful inspection of nur- 

 series which furnish the stock; (2) examination of all plants in 

 April or May, before the new shoots form, and the cutting out 

 and burning of all dead or diseased twigs, repeating once or 

 twice at intervals of one or two weeks. 



A technical description of the fungus is given. 



Ueber Exposporium Ulnti n. sp. als Erreger von Zweighrand an Jungen 

 Ulmenpflanzen. Mycol. Centralbl. i, March, 1912. Pp. 35.42. 



During June of the present year Eddel- 

 Sycamore biittel and Engelke received from Hildes- 



Leaf heim, Germany, diseased leaves of Plat- 



Disease, anus occidentalis which were infected with 



Gloeosporium nervisequum and a new 

 species of Microstror.ia which they name M. platani. The fun- 

 gus produces nearly circular dark-brown spots. As long as the 

 leaves remained on the tree the organism was not in evidence, 

 but developed well in the laboratory, where the fruit-bodies 

 emerged from the stomata and gave a grayish-white appearance 

 to the spots. Experiments are under way to show that the 

 fungus is not a new conidial stage of Grwmonia veneta, to which 

 Gloesosporium nervisequum belongs. 



Ein neuer Pile auf Platanenbldttern, Microstroma Platani nov. spec. 

 Mycol. Centralbl. I, September, 1912. Pp. 274-277. 



The biological relationships of the fungi 

 "Tar-spot" which cause the "tar-spot" of maples, and 



of which have formerly been grouped under 



Maples. Rhytismo) acerinum (Pers. )Fr., are par- 



.tially unravtelled by Muller in a recent 

 paper. Several authors had intimated a specialization into bio- 

 logical races, but no experimental proof was at hand. J. Muller 

 worked nearly twenty years to distinguish the races morphologi- 

 cally and finally concluded that the variations were not sharp 

 enough to be of specific value. 



Karl Muller performed two series of innoculation experi- 

 ments. In the first series he took potted plants of Acer plana- 

 noides, A. pseudoplatanus and A. campestre and assembled them 



