ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 407 



UredineaB.* — P. Magnus has published a note on the distribution 

 of Puccinia Geranii^ a widespread Uredine. There occur on different 

 species of Geranium a number of forms which are relegated to this 

 species of Puccinia. The European species grows only on Geranium 

 silvaticum. In other countries it is confined to other species of the 

 genus, and does not pass from one host to the other. Magnus sees in 

 it a species morphologically well characterized, but which has developed 

 geographically biologic races. 



E. Baudyst has taken up the vexed question of the wintering of 

 the uredospores of Puccinia graminis. By his experiments he had 

 already proved that a large number of uredo-forms are able to resist 

 the winter cold, and he now claims to have proved that not only does 

 the mycelium persist in the leaf but the uredo sori increase, so that the 

 spores are ready for new infection in spring. 



A. W. Borthwick and M. Wilson J have published an account of 

 Peridermium Laricis, which they record for the first time in Scotland. 

 It is the Eecidial form of Jlelampsora (or Melampsoridium) betuJina, 

 which is not rare in Scotland. The ^ecidia grow in rows on the upper 

 side of the leaves, and each group of spores is enclosed by a delicate 

 white pseudoperidium. A history of the occurrence of the fungus is 

 given by the authors. 



Centrosome in the Uredineae.§— Madame Fernand Moreau has 

 demonstrated the presence of this body during the resting periods of 

 the nucleus. She has found it in the Cseoma stage of Coleosporium 

 Senecionisy in the uredospores of llelampsora helioscopiae, and in the 

 8ecidiospores of j^ciclium Clematidis. In the two latter cases it is 

 present on the nuclear membrane as a very minute body. In Coleo- 

 sporium Senecionis the nuclei are much larger with a large nucleolus. 

 In several of these were seen a centrosome, a small round structure on 

 the membrane. 



Perennial Uredines.lj — As but little is known as to the occurrence 

 of mycelium in the permanent tissues of the host, W. J. Dowson has 

 undertaken the examination of Anemone nemorosa, the host both of 

 ^cidium leucospermum and Puccinia fusca. 



He found that the infected plants showed the mycelium of the 

 parasite in the rhizomes and in the buds, frequently in the terminal 

 buds. The hyph^e of the fungus had invaded the plerome, the peri- 

 blem, the dermatogen, and the meristematic tissue of the vegetative 

 apex, but had not entered the xylem or the phloem. 



In the buds the mycelium is intercellular ; in older portions of the 

 rhizome it is both inter- and intracellular. In the latter case it enters 

 the cell by the pits in the wall. The cells of both parasites are 

 uninucleate and develop somewhat complicated haustoria in the leaves 

 as well as in the rhizomes of the host. 



* Ber. Deutsch. Bot. Gesell., xxxi. (1913) pp. 83-7. 



t Ann. MycoL, xi. (1918) pp. 25-43. 



X Notes Boy. Bot. Gard. Edin., No. 36 (1913) pp. 79-82 (1 pi.). 



§ Bull. Soc. Mycol. France, xxix. (1913) pp. 242-3. 



11 Zeitschr. Pflanzenkr., xxiii. (1913) pp. 129-37 (1 pL). 



2 E 2 



