Algae. — Eumycetes. — Pflanzenkrankheiten. 327 



The rival views that sexual reproduction is chiefly due to inhe- 

 rent tendenc}" and chiefly influenced by outside conditions are 

 discussed at some length. On the basis of the avaible evidence it 

 is concluded that the sexual process is mainly determined by outside 

 factors. 



The causes that lead to subsequent germination of the spores 

 of Algae are sought chiefly m external conditions, although it is 

 thought that inherent tendency maj'^ in this case come into play to 

 some extent. 



Many species do not produce anj' marked resling-stage in such 

 a pond as Barton 's, and it must consequently be concluded that a 

 few individuals alwa5^s manage to persist during the minimum 

 period. 



The presence of ducks during one years of the observations 

 exerted a very marked effect on the algal flora, the filamentous 

 forms in particular being very poorly represented. 



Oedogoniinn multispornni Wood has been observed for the first 

 time in ßritain. As Wood 's original diagnosis was not very 

 satisfactory, a new emended diagnosis is published. A form of 

 Oedogoniiun Pringsheimn Cram. caused much trouble owing to the 

 very variable shape of the oogonia, which is described in the last 

 chapter of the paper. In this chapter one finds some systematic 

 notes on Spirogyra cataeniforniis (Hass.) Kütz. and on 5. quadrata 

 (Hass.) Petit. Jongmans. 



Hara, K., Ueber Polystovnella Kawagoii nov. sp. (ßotanical Ma- 

 gazine. Tokyo. XXIX. Japanese text. p. 51 — 54. 1915.) 



In dieser Arbeit wird eine Diagnose in deutscher Sprache ver- 

 öffentlicht von Polystomella Kawagoii Hara nov. sp. Der Pilz findet 

 sich auf beiden Seiten der Blätter von Prunus tnacrophylla S. et K. 

 in Kagoshima und auf P. spinulosa. 



Weiter findet man in der Arbeit die Synonj^mik von Euntycro- 

 cyclus Sciiltula (Berk. et Curt.) Hara nov. nom. {Dothidea Scultula 

 Berk. et Curt., Polystomella Scultula Speg,, Mycrocyclus Scultula 

 Sacc. et Syd., Coccoidella Scidtula v. Höhnel). Jongmans. 



Hemmi, T., On Cyclodothis Pachysandrae sp. nov. (Botanical Ma- 

 gazine. Tokyo. XXIX. Japanese text. p. 414—416. 1 Fig. 1915.) 



Enthält eine lateinische Diagnose von C. Pachysandrae. Der 

 Pilz wächst auf lebenden Blättern von Pachysandra terminalis und 

 wurde bei Maruyama (Prov. Ishikari, Hokkaido) gefunden. 



jongmans. 



Eriksson, J., Etudes sur la maladie produite par la Rhi- 

 socione violacee. (Revue gen. Bot. XXV. p. 14—30. 4 Fig. 1913.) 



L'auteur publie la description de la maladie et une diagnose 

 de l'espece: Hypochnus violaceus (Tul.) Eriks. De cette espece il 

 faudra noter comme f. sp. Dauci la forme qui a son Stade Rhisoc- 

 tonia sur les Carottes et son Stade Hypochnus sur la base des tiges 

 des Stellaria media, Myosotis arvensis, Galeopsis Tetrahit, Erysimutn 

 cheiranioides, Urtica dioica et Sonchus arvensis. On ne peut decider 

 positivement, si les formations de feutrage mycelien qu'on trouve 

 sur les Betteraves, le Rhizoctonia violacea f. sp. Betae ainsi que 



