188 SUMMARY OF CURRENT RESEARCHES RELATING TO 



He found similar conditions prevailing on dead cherry branches. He 

 therefore concludes that these represent an early generation of the 

 fungus, from the conidia of which the new flowers and shoots are 

 infected. He records a second summer generation, and a third harvest 

 generation which attacks the fruits. Culture experiments were made, 

 and advice is given as to combating the disease. 



Study of Heterosporium.* — W. J. Dowson has made an extensive 

 series of observations and of cultures on two species of Heterosporium, 

 H. echiiuilahim, and another form found on the lower leaves of beet, 

 to which he has given the name H. Betee. Artificial cultures of the 

 conidia were made on various media, as well as infection experiments. 

 He proved that H. Betse and a species of Hormodendron were sapro- 

 phytes or only very weak parasites, wounded and dying tissue only 

 being invaded. 



On the other hand, H. echhmlatwn, a very common black mould on 

 leaves of Dianthus, was found to be a true parasite ; the mycelium was 

 traced down into the living tissues of the leaf. It is intercellular, and 

 no haustoria are formed. In inoculation experiments Dowson found 

 that on the sixth or seventh day after sowing the hypli^, from germi- 

 nating conidia pierced the epidermis of the leaf probably by the middle 

 lamella, or by the stomata. After a vegetative growth in the tissues 

 of three to four weeks, conidia were again formed. They are produced 

 at the tips of the conidiophores l)y a budding process, usually in chains 

 of three. The bent and knotted appearance of the older conidiophores 

 is due to a side growth at the apex. Dispersal of the fungus is secured 

 by means of wind and rain. Perithecia-like bodies were found on 

 overwintered material of H. ecMnulafum, but their true nature and 

 '•elationship were not determined. 



Coremium-formation in Penicillium.j — It has been established 

 by several workers that the Coremium condition is confined to certain 

 :lefinite species of the genus Fenicillium. M. Munk has selected one of 

 these for culture experiments to determine the influences that induce 

 the composite growth. He gives the formula of a solution in which 

 the Coremium always appeared, and states that the formation was en- 

 couraged by the addition of nitrates and alkalis, by heightening traus- 

 jiiration, and by reducing the acid content of the atmosphere. When 

 the source of carbo-hydrate was an alcohol, more especially glycerin, 

 the appearance of the Coremium was almost certain. 



The formation was hindered by certain salts (chlorides and sul- 

 phates) l)y the addition of acids — the inorganic being more effective 

 than the organic — and by high and low temperatures. 



Other results are recorded and the physiological processes discussed. 



New Genus of Hyphomycetes.l — The new fungus described by 

 li. 8chkorbato\v as Oemmophora yurpurascens was obtained from the 



* Mycol. Centralbl., ii. (1913) pp. 1-14, 78-88, 136-44 (52 figs.). 



t Mycol. Centralbl., i. (1912) pp. 387-403. 



X Ber. Deutsch. Bot. Gesell., xxx. (1912) pp. 474-82 (figs.). 



