344 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



Variation in Phyllactinia corylea.* — E. S. Salmon finds a remark- 

 able variation in the conidial form of this species. The fungus grows 

 on a great variety of hosts (some 130 species, belonging to 52 genera), 

 and the author has gone through the material, examining and comparing 

 the Oidium whenever it was present. On certain hosts he finds constant 

 morphological differences in the conidial form ; two varieties are marked 

 by the form of the conidiophore : var. rigida, where it is rigid and 

 acicular, and var. subspiralis, where it is thick-walled and tortuous. 

 Another variety, angulata, is based on the shape of the conidia. Salmon 

 thinks that we have here an instance of a species which is undergoing, 

 or has lately undergone, a mutation period. The peculiar conidia in 

 the variety angulata occur on a wide range of host-plants, and it is a 

 curious fact that while this variety is found on such trees as Quercus, 

 Fagus, and Ulmus in America, in Europe the conidia found on trees of 

 these genera show the characters of the type. This seems to point to 

 the theory that the peculiar shape has appeared as a " mutation " 

 independent of any host. Salmon is also of opinion that biologic forms 

 exist within the species, but that it is necessary " to group all such 

 biologic forms round a clearly defined morphological centre — the 

 systematic species or variety." 



New Genus of Parasitic Fungi.f — Nicolas Jacobesco records a 

 destructive canker of lime trees caused by a fungus new to science 

 which he names Trematovalsa Matruchoti. Small longitudinal slits with 

 a black interior are first noticed in the bark of the tree. These multiply, 

 and the bark splits at right angles to the slit, until the stem or branch 

 is surrounded with wounds, and is destroyed altogether, as the fungus 

 penetrates deeper into the tissues. Jacobesco describes the perithecia of 

 the fungus, and the 4-celled spores. He also describes the spermogonial 

 and pycnidial forms which occur in succession on the infected areas. 



Balansia and Dothichloe.J — These two genera of Pyrenomycetes are 

 parasitic on grasses or carices. Gr. Atkinson has studied the different 

 species, and gives full descriptions. Balansia forms stalked or cushion- 

 like stromata in which the perithecia are imbedded. Dotliichloe is a new 

 genus proposed for those forms that have a very thin black stroma. 

 The author discusses the economic importance of these parasites, and 

 the disastrous consequences that would follow if they spread to any 

 extent, or if by changing their host, they should attack the more im- 

 portant forage plants. 



Sporulation of Yeasts of Ascomycetous Fungi.§ — The formation 

 of endogenous spores in Saccharomyces has been considered the test 

 whereby the true yeasts were to be distinguished from the budding 

 stages of other fungi. P. Yiala and P.Pacottet have been experimenting 

 with several forms of fungi in this connection, and give an account of 

 their researches. Glwospormm ampelophagum and G. nervisequum, 

 which cause respectively anthracnosis of the vine and of the plane, were 



* Ann. Mycol., iii. (1906) pp. 493-505 (3 pis.), 

 t Comptes Rendus, cxlii. (1906) pp. 289-91. 

 \ Journ. Mycol., xi. (1905) pp. 248-67. 

 § Comptes Rendus, cxlii. (1906) pp. 458-61. 



