ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 223 



true fusion occurring between the nucleoli. The secondary nucleus thus 

 formed surrounds itself with a membrane. At the same time the cyto- 

 plasm of the basidium shows a longitudinal fibrillar structure in the 

 upper part. Petri gives a detailed account of the different phenomena 

 noted in the cell and the nucleus, which divides in two, corresponding to 

 the two sterigmata of Naucoria nana. In conclusion, he examines the 

 theory of sexuality. He does not think that the synkarion has the value 

 of a fecundation, but rather that it represents the origin of a sexual 

 difference limited to the nuclei. 



Polyporus fraxinophilus.*— Hermann von Schrenk describes the 

 mischief wrought by this fungus on the white ash in North America. 

 The mycelium penetrates to the heart wood of stem and branches, so 

 destroying the tissue that the tree falls to the ground. The fruiting 

 form makes its appearance not far from the place of infection. The 

 author gives a careful description of it and of its occurrence on dead 

 wood, and suggests methods of curing the disease in the early stages. 



Oidium Tuckeri.| — Appel found that the fungus passed the winter 

 as mycelium in the tissue ;of the new wood of the vine. Numerous 

 haustoria were formed, and in the early part of the year a normal 

 mycelium was developed with conidia that again infected the growing 

 vines. 



American Mycology.! — A. P. Morgan records some interesting 

 fungi for British Columbia. He writes also a note on Corticium leuco- 

 thrix. J. B. Ellis and B. M. Everhart describe a series of new species 

 from various localities in the United States, and W. A. Kellerman 

 begins a series of mycological notes — new observations on forms already 

 recorded. 



Subterranean Fungi in Italy. § — 0. Mattirolo writes a short treatise 

 on the growing importance of these fungi in view of their connection 

 with the mycorhiza of the higher plants, and then proceeds to give a 

 detailed account of many of the forms. The whole forms part of a 

 complete monograph of these fungi now in progress. His survey 

 includes Tuberaceae, Hymenogastrea?, an unusual type of Lycoperdacete, 

 Gastrosjjorium gen. nov., which grew among the roots of grasses, and 

 some other forms, such as Onygena equina found on the decaying hoof 

 of an ox, which he includes in his underground series. 



Mycorhiza of Conifers. || — A. Moller has attacked the problem of 

 mycorhiza, and the results of his researches contradict the conclusions 

 come to by Frank and other workers. The pines of one and two years 

 growth developed well in sandy soil, more especially under a top cover- 

 ing of leaves ; but this was due to the protection against drought and 

 not to mycorhiza. He found no fungus developed on the tips of the 



* U.S.Dept. of Agric. Bureau of riant Industry, Bull. No. 32 (1903) 20 pp. 5 pis 

 See also Centralbl. Bakt., x. (1903) pp. 799-801. 



t Centralbl. Bakt., xi. (1903) pp. 143-5. 



% Joum. of Mycol., ix. (1903) pp. 161-2, 104-8, 169-70 (1 pi.). 



§ Mem. Reale Accad. Sci. de Torino, liii. (1903) pp. 331-66 (1 pi.). 



II Zeitschr. Forst. u. Jagduesen, litft 5 (1903). fee also But. Zeit., lxi. (1903) 

 pp. 329-30. 



