240 Myxomycetes. — Pflanzenkrankheiten. 



Sch>vartz, E. J., The Plasmodiophoraceae and their Relation- 

 ship to the Mycetosoa and the Chytrideae. (Ann. Bot. XXVIII. 

 p. 227-238. 1 pl. 1914.) 



The Plasmodiophoraceae ^ including the genera Plasniodiophora , 

 Sorosphaera, Tetrarnyxa, Sorodisciis, Molliardia, Spongospora and 

 Ligniera, are regarded by the author, in agreement with Maire 

 and Tison, as forming a distinct order intermediate between the 

 Mycetosoa and the Chytrideae. In support of this view the cytological 

 features of all three groups are summarised. 



In all a vegetative and a reproductive phase occur. In Plasmo- 

 diophoraceae the vegetative nuclei divide in a characteristic "cruci- 

 form" manner, and the formation of reproductive nuclei is preceded 

 by an akaryote stage. Both these features are v^anting in Mycetosoa, 

 but occur in members of the Chytrideae. On the other hand a pos- 

 sible point of relationship with the Mycetosoa may occur in the 

 conjugation of the Myxamoebae, if this can be shown to take place 

 in Plasfnodiophoraceae. The Plasmodiophoraceae differ from the 

 Chytrideae in that the resting cells are the spores, v^hereas in the 

 Chytrideae they are the spore mother-cells. In all three families there 

 appears to be an absence of karyogamj^ prior to spore-formation. 



Three new species of Ligniera are described, L. bellidis, L. 

 fnenthae and L. alismatis. E. M. Wakefield (Kew). 



Baccapini, P., SmW Exobasidium. delle Asalea. {BmW. Soc. hol. liaL 

 p. 137—138. 1912.) 



Ce Champignon a ete observe en Hol lande, dans quelques 

 localites de l'Allemagne, et, en Italie, pres de Rome; il vient 

 d'etre decouvert ä Florence sur des Azalees cultives. L'identifica- 

 tion est difficile; Petri a rapporte le parasite ä Exohasidium disco- 

 ideum, Laubert h Exobasidium japo)iicum ou Exobasidium penta- 

 sporiiim ; l'auteur incline vers cette derniere determination. 



Bonaventura (Firenze). 



Barker, B. T. P. and C. T. Gimingham. The action of Bor- 

 deaux mixture on plants. (Ann. Ap. Biol. I. p. 9—21. 1914.) 



The paper is divided into two sections, dealing v^ith a) spray 

 injury or scorching by Bordeaux mixture, and b) the penetration of 

 copper from Bordeaux mixtures into the plant. 



In experiments with apples, healthy and undamaged summer 

 foliage was found to be uninjured by spraying, where as artificially 

 or naturally wounded leaves were "scorched". The effect is consi- 

 dered to be due to soluble copper Compounds produced by the 

 action on the Bordeaux mixture of exudations from the injured cells. 



Cells with readih^ permeable walLs, such as root hairs, germ 

 rubes of fungi, etc. exert a solvent action on copper Compounds, 

 followed by absorption and consequent death. On the other hand, 

 in some cases, copper Compounds may be absorbed and transported 

 from one part of the plant to another, without injury to the cells 

 through which they pass. E. iM. Wakefield (Kew). 



Barker, B. T. P. and O. Grove. A Bacterial Disease of 

 Fruit Blossom. (Ann. Ap. Biol. I. p. 55-97. 1914.) 



The authors give a preliminary account of a disease of pear- 



