216 SUMMARY OF CURRENT RESEARCHES RELATING TO 



tion of the germinating tube, whether terminal or lateral ; the length 

 of the hyphse; their iorm, whether simple or branched; the form of 

 the haustoria and the reaction to light of the hyphse. He considers 

 that as these are fairly constant phenomena, they ought to have due 

 weight in the determination of species. The various forms of germina- 

 tion are illustrated in the text. He made mauy infection experiments 

 with conidia, and the results are given in a carefully tabulated form. 

 They serve, he holds, to establish the conclusions he had already arrived 

 at from his observations on the germination of the conidia, viz. that all 

 stages of the life-history must be considered in the diagnosis of species. 

 On many plants that lie watched throughout the season he found that 

 conidia only were produced, and the question arose as to the wintering 

 of the fungus. He is of opinion that the ascus spores have a wider 

 range of capability of infection than have the conidia ; that the Oidium 

 form has become specialised to particular busts. The same ascus fruit 

 \\ ill develop on various plants, but the resulting conidia will not trans- 

 fer from one host to another. He contrasts them with similar infection 

 results in the Uredinese. There is also a short discussion of the 

 haustoria of Sphserotheca Eumuli ; these were found to penetrate only 

 the epidermis cells of the host. 



"Shot-hole" Fungi.* — D. M' Alpine enumerates and describes the 

 so-called "shot-hole" Fungi of Australia, which attack the cultivated 

 Amygdalese and Pomese, producing round holes in the leaves as it 

 caused by shot. A callus of healing-tissue is formed round the edge 

 of the spot, and the author sees no evidence that the destruction is 

 brought about by the excretion of a poisonous substance by the mycele 

 of the fungus. There are over 20 species known in Australia, one of 

 the most frequent being Clasterosporium Amygdalearum, the pyenidial 

 stage of which is known as Phyllosticia prunicola ; also Gnomonia circum- 

 scissa, belonging to the Pyrenomycetes, of which the conidial form is 

 'Ascochyta chlorospora. 



An Arctic-Alpine Ehahdospora.j — Tycho Vestergren gives a list 

 of plants belonging to fifteen natural orders of Dicotyledons on which 

 he has found Bliabdospora cercosperma. It grows also on Monocotyledons 

 and Vascular Cryptogams, and is very frequently met with in northern 

 Europe and in Greenland. The author gives a detailed account of the 

 developments of the fungus and also the results of his experiments on 

 the germination of the spores. He got easily a growth of hyphse and 

 the production of secondary conidia, but was unable to reproduce the 

 perithceium. He has included Septoria caudata in the species, and from 

 his observations and researches he concludes that the ascomycetous 

 form of the fungus will be found in Heterospltaeria ; probably H. - atella 

 var. alpestris. 



Sexuality of certain Yeasts. % — A. Guilliermond, after describing 

 the phenomena of conjugation by isogamy occurring in certain yeasts 

 {Schizofaccharomyces octoxporus and Sch. pombe), states that these phe- 

 nomena are always accompanied by nuclear fusion. That, at least, is 



* Proc. Linn. Soc. N. S. Wales, xxvi. (1901) pp. 221-32. 



t Bihaiig k. Svensk. Vet.-Akarl. Hand!., xxvi. pt. 3, No. 12, 23 pp. and 2 pis. 



% Comptea Ilendus, exxxiii. (1901) pp. 1252-4. 



