616 Fung'» Bacteria und Pathologie. 



Ritzema Bos hat eine Erkrankung der Blätter von Anemone ja- 

 ponica beschrieben*) und als Ursache derselben Tylenchus devastatrix 

 hingestellt. Oster wald er vertritt in dem vorliegenden Aufsatz die 

 Ansicht, dass die betreffenden Nematoden keine Tylenchus, sondern die 

 wesentlich kleinere Aphelenchus olesitus seien, die auch in Chrysanthe- 

 mum indicum, Begonien, Asplenien vorkommen. Laubert (Berlin). 



ROLFE, R. A., The Genus Mystacidium. (Orchid Review. 



Vol. XII. No. 134. Febr. 1904.) 



This was founded by Lindley in 1836 to contain the S. African 

 plant then known as Angraecum capense ; it was described by the younger 

 Linnaeus in 1871 under the name of Epidendrum capense. The plant 

 was called Myst. filicorne. Harvey added 2 more S. African species 

 in 1863, and Ridley 5 more from Madagascar in 1S85. In 1864 

 Reichenbach reduced this genus to Aeranthes on aecount of some 

 similarity in the pollinarium. Bentham placed the number of species 

 of M. at 20. The author found that 19 species oecurred in Tropica 1 

 Africa, and there are probably as many more in the Mascarene 

 Islands and S. Africa, and one outlying species in Ceylon. The 

 genus is separated from Angraecum by its 2 distinet glands to which the 

 pollinia are attached each by its own stipes, while in Angraecum there 

 is only a single stipes and gland. The allied genus Listrostachys is 

 characterised by having 2 distinet stipes attached to a single gland. 

 Saccolabium is more nearly allied to Angraecum than are Listrostachys 

 and Mystacidium. W. C. Worsdell. 



SIMON, F. B., Untersuchungen über die Gifte der Strep- 

 tococcen. (Cbl. f. Bakt I. 0. XXXV. 1904. p. 308 ff.) 



Nach Verf. erzeugen die pathogenen Streptococcen zwei verschie- 

 dene Toxine, die unabhängig von einander entstehen: ein schwächeres, 

 das erst nach Zertrümmerung der Zellen gewonnen werden kann und 

 ein viel stärker wirkendes, das von selbst ausgeschieden wird. Letzteres 

 entsteht aber nicht permanent, sondern nur unter der Einwirkung der 

 Abwehrstoffe des Thierkörpers; mit der durch letztere bewirkten Hemmung 

 der Zellenvermehrung beginnt die Toxinausscheidung. 



Hugo Fischer (Bonn). 



Smith, E. F. and D. B. Swingle, The.dry rot of potatoes 

 due to Fusarium oxysporum. (U. S. Dept. Agric. Bureau 

 of Plant Industry Bull. LV. 1904. p. 1—64.) 



Dry rot of the potato has been known both in this country and 

 abroad for a long time. The best work has been done in Germany. 

 The disease usually enters the plant by means of the roots and slowly 

 spreads until the whole subterranean portion of the plant is affected. 

 When the plants are about a foot high the leaves assume a lighter 

 green color than the healthy ones, turning after a considerable time to 

 a deeided yellow or brown. With the change of color they lose their bright 

 glistening appearance and begin to curl and roll up. When the plants 

 are mature the affected ones are noticeably shorter than the sound ones; 

 the roots have become so weakened that the top lies prostrate 

 on the ground in a characteristic manner. They can be pulled 

 up much easier than the sound ones because of the rotting of the roots. 

 These are usually covered with a pink, white, or even reddish 

 growth of mycelium. The mycelium invades all parts of the root, but 

 more especially the bark. It is present in the water duets, but is not 

 especially abundant there. The fungus was found in tubers of 



*) Referirt im Bot. Centralbl. 1904. Bd. XCV. p. 210. 



