ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 643 



Pigment-formation in Merulius lacrymans.* — C. A¥ehmer points 

 •out that ill the open the iiiycelium of this fungus takes on here and there 

 a lemon-yellow colour. In cellar cultures of the fungus the colour changes 

 to brown. The yellow colour in the cultures was very persistent and was 

 almost independent of changes in the nature of the culture media. The 

 brown colour appears later and may possibly be identical with that of 

 the spores. 



Fungi parasitic on Lichens.j — Abbe Vouaus has made a study of 

 these microscopic fungi, which are divided into three groups, Pyreno- 

 mycetes, Discomycetes, and Fungi imperfecta In the present issue he 

 deals with the first group, which is by far the most numerous, and he 

 describes all the species so far as they have been recorded, giving the 

 microscopic details, together with habitat and locality. 



Studies on Mycorhiza Formation. J — J. Fuchs has attacked the 

 problem of determining the Mycorhiza fungi by making sterile cultures of 

 seedling trees and of various fungi, and then introducing the mycelium 

 to the roots. He obtained pure cultures of a number of fungi, but he 

 was successful in only one case in obtaining mycorhizal growth — the 

 mycelium of Golly bia macro ur a penetrated the root-cells of Finns 

 Strohus, and the Mycorhiza formed was indistinguishable from the 

 normal form. Occasionally it was found that mycelium had entered 

 the cells which did not correspond with the cultivated fungus, and it 

 was surmised that the mycorhizal fungus may have been in the seed. 

 Fuchs thinks the connexion between the roots and the fungus is one of 

 a tolerated parasitism, causing at first a very slight damage to the root- 

 cells, and finally becoming harmless. 



Symbiosis of Fungi with the Higher Plants. § — J. Zillner 

 discusses the different cases in which fungi are associated with 

 Phanerogams, mostly as Mycorhiza fungi. He considers that the chief 

 function of the fungus is to supply water to the roots of the host, 

 partly in an indirect way by breaking up the starch into more osmotic 

 solutions, and thus setting up a current of water from the soil. In 

 soils poor in nitrogen the fungus is proliably of service in the direct 

 assimilation of nitrogen, but only in some cases, as in others the fungus 

 dies in the absence of soil nitrogen. The fungus itself gains by 

 securing easily assimilated carbohydrates. Parasitic fungi are also 

 reviewed, and the relation between the host and the parasite examined. 



Black Spot of Roses. II — F. A. Wolf has studied the development 

 of the fungus that shows on rose leaves as a somewhat circular black 

 spot, and is known as Adinonema Rosae. The black colour is due not to 

 the fungus, but to the disintegration of the underlying cells of the host. 

 The author has cultivated the fungus, and describes in detail not only 



» Ber. Deutsch. Bot. Gesell., xxx. (1912) pp. 321-9 (3 figs.). 



t Bull. Soc. Mycol., xxviii. (1912) pp. 177-208. 



:: Bibl. Bot. (1911) 33 pp. (4 pis.). See also Ann. Mvcol., x. (1912) pp. 427-8. 



§ Beih. Bot. Gentralbl., xxviii. (1912) pp. 475-84. 



II Bot. Gaz., liv. (1912) pp. 218-34 Q pl.j. 



