310 SUMMARY OF CURRENT RESEARCHES RELATING TO 



reverts to the early form, and the change could be considered as due to 

 hindrances in development. Similar changes can be brought about 

 artificially by various unfavourable conditions. Figures are given of the 

 different spore-germinations and of the differences in the leaves. 



Uredineae. — 0. Treboux * has continued his infection experiments 

 with various Uredineae, details of which are given. In connexion with 

 his experiments on Puccinia Polygoni-amphihii, he obtained aecidia on 

 Geranium coJumbinum and G. rotimdifoUum, in addition to others pre- 

 viously noted. Puccinia permixta Syd., which grows on Di])lac]me 

 serotina, formed secidia on Allium globosum, A. porrum, Siud A. sativum. 

 Other additional results were obtained with Puccinia stipina, a pleo- 

 phagous species : with the teleutospores of a Puccinia on Oarex steno- 

 phylla ; with Puccinia glumarum, in which he found there were no 

 biological species ; with P. agropyrina, which he proved to be the same 

 as P. dispersa. A number of experiments are also recorded on P. 

 coronata and P. coronifera, and results are given of infections with 

 Uromyces, of which the j^ciclium stages grow on species of Euphorhia. 



A. de Jaczewski j describes an instance of a fruit being attacked by 

 a Uredine. It occurred on apples, on which the Roestelia, or jEcidium 

 stage of Gymno sporangium tremelloides, formed a large blotch. The 

 author gives a general account of Gymtiosporangium. 



G-. G. Hedgecock J records field observations on some Uredineae. 

 He found in Colorado that a number of trees of Pinus ponder osa were 

 attacked by Peridermium Jilamentosum, the alternate stage of which, 

 Crornartium filamentosum, is parasitic on Castilleja plants. He further 

 remarks that where cattle or sheep graze in the forest these plants are 

 eaten down, and there is little chance of the fungus spreading. 



Hymenomycetes of Varena.§ — C. Massalougo noticed the great 

 abundance of large fungi in the pine woods round Yarena after a very 

 wet summer. Massalongo describes the type of vegetation in the woods, 

 not only the different pine trees but the underbrush of Gcdluna, 

 Vaccinium, etc., with mosses, hepatics, and ferns. He gives a long list 

 of the fungi obtained. 



Studies on Pleurotus ostreatus and Pleurotus ulmarius.|| — 

 CD. Learn selected these two gilled species of fungi to examine their 

 action on the woody tissues on which they are parasitic. He describes 

 the methods of germinating the spores, sterilizing the specimens of 

 wood used in the cultures, etc. Diseased wood was also prepared and 

 examined microscopically. In wood of Acer saccharimi which had been 

 rotted by Pleurotus ostreatus, it was found that the hyphae appeared to 

 traverse the vessels, or to follow the course of the vessel some time before 

 diverging ; they may also branch off profusely and enter the medullary 

 rays. The hyphae pass through the pits in the wall of the vessels, and 



* Ann. Mycol., x. (1912) pp. 557-63. 



t BuU. Soc. Mycol. France, xxix. (1913) pp. 165-9 [(1 fig,). 



X Phytopath., iii. (1913) pp.'15-17. 



§ Bull. Soc. Bot. Ital., 1912, pp. 227-31. 



11 Ann. Mycol., x. (1912) pp. 542-56 (3 pis.). 



