Fungi, Bacteria und Pathologie. J 59 



MlDDLETON, T. H. and POTTER, M., C, Black Dry Rot in 

 Swedes. (Journal of the Board of Agriculture. Vol. IX. 

 No. 1. June 1902. p. 25. 1 Plate.) 



An account of a bacterial disease in Brassica napus which appeared 

 in the county oi Durham in 1901. 



The organism (which is distinct froni Pseudomonas destructans 

 previously described as destroying Turnips) was isolated and the disease 

 was artificially produced by inoculation. The bacterium possesses a 

 single polar flagellum and thereiore belongs to the genus Pseudomonas. 



G. Massee and A. D. Cotton (Kew). 



MURRILL, W. A., The Polyporaceae of North America. I. 

 The g e n u s Ganoderma. (Bull. Torrey Bot. Club. XXXI. 1902. 

 p. 599—608.) 



An attempt is made to present in order the members of the luciduc 

 group of Polyporus occurring in North America. A brief history of 

 the genus is given together with a key, and description, synonomy, habitat, 

 distribution, and notes on each of the seven species: Ganoderma tsugae 

 sp. nov., Ganoderma pseudoboletus (Jacq.), Ganoderma sessile sp. nov., 

 Ganoderma parvulum sp. nov., Ganoderma. Oerstedü (Fries.). Ganoderma 

 yonatum sp. nov., Ganoderma sulcatum sp. nov. 



Notes are made on the following questionable species: Fontes in- 

 crustans Fries., G. nutans (Fries.) Pat., G. nitens (Fries.) Pat., G. ne- 

 glectum Pat. P. Spaulding. 



Percival, John, „Silver leaf" disease. (Journal of Linnean 

 Society Botany. Vol. XXXV. No. 245. July 21 1902. 

 p. 390. 1 plate. 5 figures.) 



The author has investigated the disease oi Plums and other species 

 oi Prunus, which is known as „Silver Leaf'; and he attributes it to the 

 presence of the fungus Sterenm purpureum in the roots. 



Specimens of „silver leaf" trees were examined from various loca- 

 iries, and in each case the root-stock was found to be diseased ; 

 the wood showing internal discoloration and containing fungal-hyphae 

 at the junetion of the dead and living tissue. Portions of the diseased 

 roots cut into lengths and kept in damp Chambers gave rise to a dense 

 white mycelium and finally to sporophores of Stereum purpureum. Healthy 

 trees were inoculated with pieces of the sporophores of this fungus in 

 March: eight or nine weeks later the leaves began to show the silvery 

 character. 



This latter appearance is due to intercellular spaces filled with air 

 present beneath the cuticle along the line of union of the epidermal 

 eells. No mycelium is to be found in these leaves or in any of the 

 branches; though the wood of the stem is discolored, in advanced cases. 

 infection is thought to take place below gronnd and apparently through an 

 unwounded surface. A. D. Cotton. 



Ricker, P. L, Notes on Some West American Fungi. 

 (Journal of Mycology. VIII. p. 125—128. Oct. 1902.) 



A list of fungi collected by Messrs. E. D. Merrill and E. V. 

 Wilcox in Wyoming and Idaho during the Stimmer of 1901, also of 

 fungi found upon grasses in the Herbarium of the U. S. Department of 

 Agriculture. G. G. Hedgcock. 



