328 Eumycetes. 



7. Finally, the fact that the form here was found only upon 

 plum, although the apple trees stand within a few feet of some 

 heavily infected plum trees, coincides with the observations of many 

 investigators that S. cinerea occurs predominantly upon stone fruiis. 

 However as a resuli of his inoculation tests, the writer has found 

 that the fungus in Illinois may also inlect pome fruits, at any 

 rate under laboratory conditions, and Ewert also reports that 5. 

 cinerea may infect pome fruits. M. J. Sirks (Haarlem). 



Edgerton, C. W., A method ofpicking up Single spores. 

 (Phytopathology. IV. p. 115-117. 1914.) 



In mycological or pathological work it is frequently necessary 

 to isolate Single spores or asci and transfer them to culture media 

 where their development can be watched. In order to make sure 

 that a colony really develops from an individual spore or ascus. it 

 is necessary to pick this out of the mixture and transfer it to the 

 desired culture medium. The author describes a simple instrument, 

 which gave fairly good results. The principle involved is not new, 

 but the simplicity of the apparatus may appeal to other workers 

 along this line. Therefore the writer publishes his description, which 

 must be read in originali. M. J. Sirks (Haarlem) 



Melhns, I. E., A species of Rhisophidium parasitic on the 

 oospores of various Perono&poraceae. (Phytopatholog}" IV. p. 

 55-62. 1914.) 



In his studies of oospore germination of various Peronosporaceae, 

 begun after a method had been worked out for germination of the 

 asexual spores, considerable difficulty has been encountered b}' the 

 writer, due to a parasite, Rhisophidimn pollinis, which attacks the 

 ripe oospores when they are placed in water to germinate. Similar 

 difhculties have been reported alread}^ in 1863 by De Bary, and 

 since by some other workers, though the relations of the infecting 

 fungus was not clear. The writer has made extensive researches 

 about this infection of germinating oospores of Cystopiis hliti by the 

 Rhisophidium-s'pecie?,. The method used by the author is described; 

 then foUow the observations and experiments, communicated in 

 detail. Infection-experiments made it piain, that Rhisophidium poUinis 

 is quite cosmopolitan in its nature in that it grows readily on the 

 oospores of three different genera of Peronosporaceae. No attempts 

 were made to infect conidia of the Peronosporaceae, but it is very 

 probable, in view of the results obtained with Rhisopus- zomdAdi, that 

 they also can be infected. Another experiment made it clear that 

 the Rhisophidium pollinis parasitic on the oospores of Cystopus hliti 

 may also become a parasite on pollen (i. c. of hyacinth and calla-liljO- 



The Rhisophidium poUinis, as studied by the writer, also pro- 

 duces a thick walled resting spore. These were not ver}^ numerous 

 and developed only in old cultures, contradictory to the observations 

 of earlier authors. But these authors studies a Rhisophidium-species, 

 predominatingly parasitic on algae, hosts that are easily destroyed 

 and low in food value, while the oospores, used bj^ the writer. are 

 not easily destroyed and contain an abundance of food in proportion 

 to the volume. Perhaps this gives an explanation lor the difference 

 in resting spore-development between the writers' results and ihose 

 of other investigators. M. J. Sirks (Haarlem). 



