192 SUMMARY OF CURRENT RESEARCHES RELATING TO 



filament. They are provided with several evacuating tubes. Oogonia 

 are less variable and without evacuating tubes ; aotheridia entirely 

 penetrate the oogonia. There may be more than fifty oospores in one 

 oogonium ; they are globose and smooth, and escape by the decay of the 

 enclosing membrane. 



Perennial Mycelium of Phytophthora infestans.* — There has been 

 considerable diversity of opinion as to the persistence of the potato- 

 disease fungus in the tubers, and as to whether the tubers give rise to 

 healthy or infected plants. I. E. Melhus has undertaken cultural 

 experiments to decide these questions. He found that in the large 

 majority of cases the sprouts from infected tubers were also infected by 

 the fungus, and very commonly the fungus fruited. Experiments were 

 also made as regards the stalks and leaves, and Melhus found that 

 though some diseased tubers produced healthy plants others were very 

 seriously infected, and the mycelium spread up to the surface of the 

 soil, where aerial spores were found, which again gave rise to secondary 

 infection. 



Leptostromacese.'j' — H. Diedicke publishes a critical revision of many 

 of the genera of Nectrioideae, Excipulacese, and Melanconiese. Several 

 of the genera he finds to be synonyms ; in other cases he has extended 

 the descriptions from his own observations. The genera omitted from 

 the survey gave no occasion for criticism. 



Microthyriacese.J — F. Theiszen publishes a paper containing critical 

 and descriptive notes on various genera and species of this family of 

 Ascomycetes. He records a number of new species and several new 

 genera, Amazonia, Thallochsete, and Myxomyriangium, the latter with 

 brightly coloured minute stromata crowded on a thin olivaceous subicu- 

 lum. Another new genus, Hysterostoma, with 2-celled brown spores, 

 belongs to the Dothidiacese. 



Morphology and Physiology of Penicillium.§— K. Schilbersky has 

 made experimental studies on the coremium growth of Penicillium 

 especially in P. glaucum. Several species he found were characterized 

 by the tendency to form the compound growth, some of them irregu- 

 larly and independently of any external influence {P. luteum and 

 P. glaucum), others more constantly and in all conditions (P.granulatum 

 and P. clav/forme). On sugar, gelatin, etc. P. Juglandis always formed 

 coremium growths. 



The coremia of P. glaucum are formed somewhat rarely : they con- 

 sist of upright parallel sparingly branched stalks, with the spores produced 

 at the summit. Schilbersky found these coremia most frequently on 

 pears not yet fully ripened ; on apples and soft pears they appeared very 

 rarely, but a good growth was obtained on the skin of lemons. He con- 



* Centralbl. Bakt., xxxix. (1913) pp. 482-8. 



t Ann. Mycol., xi. (1913) pp. 528-45. 



% Ann. Mycol., xi. (1913) pp. 493-511 (1 pi. and 7 figs.). 



§ Math. Naturw. Ber. Ungarn, xxvii. (1913) pp. 118-30 (2 figs.). 



