350 Pflanzenkrankheiten. — Bacteriologie. 



purpureum is an active agent in producing the disease of Plum 

 trees know as Silver leaf. 



A number of inoculation experiments on young trees were 

 carried out, 3 methods being employed, namely, 1) by means of 

 natural sporophores of the fungus 2) by mycelium grown from spores 

 in pure culture and 3) by spores. The first method of inoculation 

 almost invariably resulted in silvering of the foliage, and the second 

 frequently so; the controls in both cases remaining free from disease. 

 Spore-inoculations have so far yielded few results. 



Though not denying the possibility of other causes the author 

 strongly believes in Stereum purpureum being the agent chiefly 

 responsible for "Silver leaf" in the fruit-growing districts of England. 



A. D. Cotton. 



. . ^ 



Möbius, M., Pilzgallen an Buchenstämmen. (Ber. senckenberg. 

 naturf. Ges. Frankfurt a. M. XLII. 1. p. 7—12. 6 Abb. 1911.) 



Bereits Darwin berichtet in seiner „Reise eines Naturfor- 

 schers um die Welt" von einem vegetabilischen Naturprodukt, das 

 für die Feuerländer als Nahrungsmittel von Bedeutung ist. „Es ist 

 ein kugeliger, hellgelber Pilz, der in ungeheurer Menge an den 

 Buchenstämmen wächst". Berkeley benannte den auf Fagus betu- 

 loides vorkommenden Pilz Cytlaria Darwinii. Während die Indianer 

 noch heute den Pilz, dessen krebsartige Geschwulste an den Buchen 

 Patagoniens sehr häutige Erscheinungen sind, eifrig sammeln und 

 geniessen, gibt N. Alboff an, dass er vollkommen geschmacklos sei. 



Verf. beschreibt ein von Baron Dr. von Schrenck-Notzing 

 (Leipzig) aus dem Feuerland mitgebrachtes Exemplar der Cyt- 

 taria Geschwulst und bildet Zweige mit den Auswüchsen, einen 

 Durchschnitt durch eine Galle des Pilzes sowie Blätter von Fagus 

 betuloides ab. W. Herter (Tegel). 



Bottomley, W. B., The structure and phy siological signi- 

 ficance of the Root-nodules of Myrica-Gale. (Proc. Rov. 

 Soc. LXXXIV. B. 571. p. 215-216. 1911.) 



Roots were examined from plants from various localities. The 

 nodules form Clusters originating from the outgrowth of lateral roots 

 and not by dichotomy of the apical meristem (e. g. Cycas). The 

 nodules contain a tetrarch vascular bündle, an endodermis with 

 oil-drops, cells with oil-drops, and enlarged cells with bacteria in 

 form of small rods. Towards the apex of a nodule, zooglea threads 

 of bacteria pass from cell to cell. The cortical cells of young lateral 

 roots become infected before emerging from the main root, normal 

 growth is checked, but by division and growth of the cells con- 

 taining bacteria the nodule is formed. When the nodule reaches its 

 füll size the end of the stele surrounded by a few cortical cells 

 grows on and forms a thin rootlet; around this three brancbes or 

 nodules arise endogenously, the repetition of this gives rise to 

 Clusters. No fungal hyphae were observed, but there were filaments 

 of bacteria. Identity with Pseudomonas radicicola of nodules of 

 Leguminosae was established by pure cultures. After incubation 

 for 7 days, cultures gave a fixation of 2'05 mgrm. of nitrogen over 

 controls. Myrica plants without nodules were planted in a green- 

 house in soil free from nitrogen, and these died; others with no- 

 dules lived. W. G. Smith. 



