282 SUMMARY OF CUERENT RESEARCHES RELATING TO 



irregular, coral-like, leaden-grey bodies of all sizes up to a diameter of 

 4 era. They were filled with a dark brown conglomerate of spc.res 

 which were first formed in the root permeated by hyphas, but after- 

 wards increased so greatly in number that the root was burst open, 

 and the mass of spores exposed, which then either enveloped the finer 

 roots with a weft, or else formed the coral-like bodies which appeared 

 like appendages to the roots, and were buried in the soil. The mass 

 of spores was surrounded by a thin weft of colourless hyphaj, and was 

 composed in the centre of from one to three large dark brown spores, 

 with a diameter of 12-16 jx, surrounded by a number of smaller spores ; 

 the nearly or quite round mass having a diameter of 30-40 /x. I'he 

 fungus belongs, undoubtedly, to the genus Urocystis, but is charac- 

 terized by its subterranean habit and large size. 



The same writer also records the discovery of red masses of long 

 multicellular teleutospores in leaves of Pyroln minor, belonging to 

 Ureilo Pyrolce. The structure of the teleutospores shows the fungus to 

 belong to the Coleosporei, and to be closely related to Coleosporium 

 Ledi. The correct name is therefore Chrysoniyxa Pyrolce. The 

 author believes it to be connected genetically with ^cidium conorum 

 Picece found in proximity on cones of Picea excelsa. 



Species of Hysterium parasitic on Cruciferae.*— K. Prantl has 



investigated the development of Hysterium nervisequium, macrosporum, 

 and pinastri on the leaves of various Cruciferae. He finds that after 

 the germinating hyphae have perforated the ej^idermis, weeks, months, 

 or even years may elapse before any signs of disease are visible on the 

 leaves. The fructification takes from two to seven years to mature. 

 According to the nature of the host, the disease may be either chronic, 

 when the leaves do not lose their colour for a considerable time, and 

 remain on the plant until the parasite is mature ; or acute, when the 

 leaves at once both lose their colour and drop from the tree. 



Ch.estnut-disease.t — Gr. Gibelli describes in detail the disease 

 which extensively attacks chestnut-trees in Italy and the South of 

 France. Abandoning his previous theory that it is the result of 

 depauperation of the soil, the author now hesitates between attributing 

 the disease to fine mycelial overgrowths of the apices of the roots, or 

 to pycnidia detected by him on the diseased roots. 



Plant-diseases caused by Fungi.J — E. Hartig publishes an ex- 

 haustive account of the various diseases caused in trees, cultivated 

 crops, and other plants, by the attacks of fungi. He discusses 

 several difficult questions which arise in connection with the subject, 

 as for example the apparent hypertrophy of the tissue of the host, 

 without any evil consequences resulting from the attacks of some of 

 these parasites. 



* Foistwissensch. Centralbl., 1880, pp. 509-13. See Bot. Ceutralbl., i. (1880) 

 p. 1261. 



t Gibelli, G., ' La malattia del Castagno,' Modena, 1880. 



i Hartig, R., 'Ueber die durch Pilze bcdingten Pflaiizenkvankhciten,* 

 Miinchen, 1880. See also supra, p. 273. 



