On the Morphology and Development of Phoma Richardiae n. sp. 
305 
may be explained, also, on either ground. But the gemmae begin to 
assume a dark colour before the halo appears; the latter spreads from 
the gemmae, gradually extending its edge further afield, and always 
being densest in the centre; further, the brown conidia on the “luft“ 
mycelium — which do not come in contact with the agar at all — also 
develop a dark brown colour. These facts taken together indicate that 
the cause of the colouring, both of fungus and agar must be sought for 
in some vital process, rather than in a purely chemical change in the 
food medium ; though the food medium obviously exerts an influence, as 
witness the variation on different media. 
The theory of self-poisoning receives support from the behaviour of 
the pycnospores. It is to be noted that the changes observed, occurred 
only where a great number of spores were present in a limited space, 
under conditions where germination was possible. It the plant does 
excrete a poisonous substance, the most marked effects would be looked 
for where a great number of spores germinated, or attempted to germinate 
in a confined space Whatever the cause, it is evident that the spores 
soon find themselves in the same position as the mycelium in an old 
culture; they either grow out to gemmae direct, or pass over at once to 
the formation of brown conidia. Those at the edge of the drop which 
can send out mycelium into the air, retaining only sufficient contact with 
the liquid to permit of food absorption, and thus having comparatively 
little surface exposed to poisonous effects, are alone capable of normal 
growth. Were it purely a matter of competition it would be expected 
that the outermost spores in the drop would fare the worst; and that 
the rest would tend to form thin straggling hyphae instead of large conidia 
and gemmae rich in oil. It is difficult to account for the spore changes 
on the assumption that they are caused by the purely chemical alteration 
in the food medium, consequent on the absorption of some of their in¬ 
gredients, since they take place in a solution of Cane Sugar in distilled 
water, and in ordinary tap water. (Schluß folgt.) 
Referate. 
JAVILLIER, M., Influence du zinc sur la consommation par 
VAspergillus niger de ses aliments hydrocarbonés, azotés 
et minéraux (Compt. Rend. Acad. Sc. 1912, 155 , Nr. 2, 190—193). 
Bei Anwesenheit von Zink ist Aspergillus niger imstande, alle für 
sein Wachstum notwendigen Nährstoffe besser auszunutzen; der Pilz haus¬ 
haltet sparsamer, indem er, zugunsten seines Wachstums, wenig für seine 
Erhaltung verbraucht. So verbrauchte z. B. der Pilz für die Bildung 
von 1 g Trockensubstanz bei Anwesenheit des Stickstoffs in Form von 
Ammoniumtartrat nach zweitägiger Cultur ohne Zink 11,45 g, mit Zink 
3,70 g Zucker. Der Verbrauch von Stickstoff betrug bei Abwesenheit 
von Zink 0,091, bei Anwesenheit desselben 0,054 pro Gramm Trocken¬ 
substanz, wenn der Stickstoff als Ammoniumtartrat in der Lösung ent¬ 
halten war. 
Die Zusammensetzung der Asche von Aspergillus niger wird eben¬ 
falls durch die Anwesenheit von Zink beeinflußt. Der Gehalt an Si und 
20 
Mycologisches Centralblatt, Bd. II. 
