Pflanzenkrankheiten. 577 



der in und um sich das in der Zelle vorhandene Pilzelement an- 

 sammelt. Von diesem Energiezentrum aus strebt der sich separie- 

 rende Pilzkörper nach der Zellwand hin. Es entsteht dabei ein 

 birnenförmiges Ding, dessen Stielspitze an die Wand stösst und 

 hier seinen Austritt in den anstossenden Luftraum oder das benach- 

 barte Zelllumen sucht. Ausserhalb der Ansatzstelle bildet sich ein 

 junger Pilzfaden. Eine Mehrzahl zusammengehörender und zusam- 

 menlebender Zellen arbeiten hierbei gemeinsam. Tag für Tag breitet 

 sich das Fadennetz mehr und mehr im Gewebe aus, jetzt wesent- 

 lich unterzellular, bis nach 8 — 15 Tagen ein zusammenhängendes 

 Pseudoparenchym und endlich ein sporenerzeugendes Hymenium 

 fertig gebildet hervortritt. Jongmans. 



Kusano, S., On the chloranthy of Prunus Mume caused by 

 Caeoma Makinoi. (Journ. Coli. Agric. Imp. Univ. Tokvo. II. 6. 

 p. 287-326. PL 17—18. 3 Textfig. 1911.) 



The author describes the chlorantic flower and the changes in 

 the calix, the corolla, the androecium and gynaeceum, the develop- 

 ment of the diseased flowerbud. He discusses the relation between 

 the development of the fungus and the malformation of the floral 

 organs and more specially of the anther and the ovule. The third 

 part of his paper are etiological considerations on chloranthy. At 

 the end of the paper the author gives among others the following 

 general remarks. 



The chloranthy of Prunus Mume is due to the action of the 

 fungus parasitic in the flowerbud. The protoplasm of the undiffe- 

 rentiated organ reacts to the Stimulus exerted \>y the mycelium and 

 the course of development is modified in the way mentioned in 

 details in the first part of the paper. The Stimulus of the mycelium 

 for causing chloranthy is very limited in extent. The development 

 of Chlorophyll, attended by other external and internal modifications 

 of the floral organs, extends pari passu with the extension of the 

 mycelium. A strong malformation is correlated with a vigorous 

 development of the fungus, so that, when the conditions are such 

 as to inhibit the füll development of the latter, the infected portion 

 of the flower undergoes less malformation. 



Complete chloranthy does not result unless the necessary action 

 of the fungus operates upon the bud at a certain stage of its develop- 

 ment. Its Operation at earlier stages develops the bud into a shoot, 

 while at later stages it produces incomplete or no chloranthy. 



The autor discusses the opinion of Velenovsky on abnorma- 

 lities. The abnormality in question here should, according to Vele- 

 novsky, be included in the pathogenetic group. The autor however 

 looks upon abnormalities of this kind as atavistic phenomena, and 

 is of the opinion that chloranthic flowers throw some light on the 

 morphological nature of floral organs in general. 



Reviewing now, as a whole, phenomena of the chloranthy and 

 the associated changes caused by the fungus, the relation between 

 the time of infection and the degree of the ensuing malformation 

 will become very apparent. This may be easily seen from the fol- 

 lowing series of diseased buds and their derivatives thus far obtained 

 by the autor. 



a. Bud looks like a normal leafbud, outer budscales attacked 

 by the fungus; develops into a shoot. 



Botan. Centralblatt. Band 120. 1912. 37 



