Eumycetes. — Pflanzenkrankheiten, 409 



tosperma schiffsankerförmigen — Conidien unterschieden) mit 1 

 Art: T. singulare auf Ubnus parvifoUa, Urocystis Dioscoreae diWi Dios- 

 corea Tokoro, Dbneriiim elegans auf Pasania cuspidata, Uleontyces 

 decipiens auf Quercus thalassica, Cercospora profusa auf Acalypha 

 australis. Neger (Tharandt). 



Bayer, E., Die Zoocecidien der Insel Born hol m. (Verhandl. 

 k. k. zool.-bot. Ges. Wien. LIX. p. 104-120. 1909.) 



Verf. und sein Bruder sammelten emsig Zoocecidien auf Born- 

 holm; auf 64 Wirtspflanzen konnten sie 112 Arten von Gallen 

 feststellen, welche von 108 Cecidozoen erzeugt wurden. Frühjahrs- 

 formen konnten nicht berücksichtigt werden. Neue Formen werden 

 nicht beschrieben. Matouschek (Wien). 



Pole Evans, J. B., The mildews of the Grape Vine. (Trans. 

 Agric. Journ. VII. 26. p. 213—214. 1909.) 



Plasuiopara viticola, (Berl. & De Tonil. Downy mildew, attacks 

 all green parts of the vine, usually appearing first as a glistening 

 growth on the lower surface of the leaves, which shortly wither and 

 fall. In consequence, the grapes fail to mature, myriads of resting 

 spores are formed within the affected tissues, which retain their 

 vitality in the soil for years, The fungus is a true parasite, living 

 upon the tissues of its host. 



Uncimila spiralis, (Berk. & Gurt.). Powdary mildew, appears on 

 Upper surface of leaves as dull white patches extending over the 

 whole leaf, which curls up characteristically. Small black resting 

 spores are formed towards the end of the season. The fungus also 

 attacks the berries, and lives almost entirely on the surface of its 

 host, extracting its food by means of haustoria. W. E. Brenchley. 



Potter, M. C, Leaf-Spot of Odontoglossum Uro-Skinneri. (Gard. 

 Chron. XLV. March 6. 1909. p. 145-146. 4 figs.) 



The disease described forms slightly-raised black spots on the 

 under sides of the old and fully grown leaves. Each spot is sur- 

 rounded b}^ a translucent border. Sections through the young stages 

 of the spot show that there is an accumulation of browm mucilage 

 in the respiratory cavities of the stomata, which exudes into the 

 stomatal openings. In later stages the mucilage coUects in large 

 masses spreading through the h3'podermal cells and into the internal 

 tissues of the leaf. In this position the gum is colourless. The cells 

 in the infected areas separate along the middle lamella, and the 

 Contents become much disorganised. The chloroplasts split up into 

 a number of small bodies, and in common with the nucleus and 

 protoplasm finally disappear. 



No fungus mycelium nor an}' trace of a wound was found, nu- 

 merous bacteria were however noted in the cells surrounding the 

 tissues in the initial stages of gum forraation, and the author suggests 

 that an invading bacterium may exercise a destructive action upon 

 the protoplast producing a formation of gum, Inoculation experiments 

 were unsuccessful. The spot was noted to be more prevalent on 

 plants grown in a moist atmosphere; when these Avere removed to 

 a drier one its development was checked. A. D. Cotton (Kew), 



