180 SUMMARY OF CUEIIENT KESEARCHES RELATING TO 



He succeeded in developing the fecidium stage on Picea excelsa^ 

 Similar experiments with Pucciniastrum Circsese on Gircsea lutetiana 

 were followed by the growth of tecidia on Ahies peciinata on the under 

 side of the leaves ; pycnidia grew on both sides. He was able to prove 

 also that Coleosporium Senecmm forms recidia on Pinus mo/itanao^swell 

 as on P. silrestris. He made further experiments on the species of 

 Senecio affected by the Uredine. 



Fischer also gives results of experiments to test the hereditary 

 susceptibility of hosts to the fungus parasites. Susceptibility did not 

 follow on the morphological character of the leaves. More research i.* 

 necessary. 



He notes the presence of an exotic fungus, a species of Aseroe, in 

 Europe. It appeared in a garden at Hengelo in Holland. Fischer 

 discusses the specific determination ; it seems to be nearest to 

 A. australiensis. 



A revision of the Exohasideae on Ericaceae, is also outlined by the 

 writer. He distinguishes two groups : those that cause galls and 

 swellings, and those that form a layer on £he under side of the leaves,. 

 covering often the whole surface. A. L. S. 



Morphology of the Genus Actinomyces. — The material for the study 

 of this genus was isolated from soil collected in Cambridge, Massa- 

 chusetts. Other forms were obtained from Porto Eico, Cuba, etc.^. 

 and the potato-scab organism was taken from a diseased tuber. From^ 

 these numerous specimens, representing probably more than 100 species,. 

 a developmental study has been carried out by Charles Drechsler. 

 {PjoL Gciz., 1919, 67, 65-83, 147-G8, 8 pis.). As a result of his 

 observations Drechsler places the fungus among the Hyphomycetes. 

 He was able to follow every stage of growth in his cultures up to the 

 formation of spores. The sporogenous hyplife of most species are coiled 

 in close spirals ; the number and diameter of the coils and the direction.' 

 of the rotation (whether dextrorse or sinistrorse) are specifically constant. 

 He describes and figures eighteen different forms, indicated by numerals. 



A. L. S. 



Studies in the Agarics of Denmark. — Jakob E. Lange {Banska 

 Bot.Arlciv, 1913-15, 1, No. 5, 1-40, 2 pis., 1 coloured) gives first a 

 general introduction explaining that the publication now undertaken 

 is meant to serve as the letterpress of a forthcoming " Illustrations of 

 the Agarics of Denmark." The group here studied includes the genu» 

 Mycena, and he emphasizes the importance of microscopic characters in 

 determination — spores, their arrangement on the gills and the cystidia.. 

 He gives a key to the genus based mainly on such characters. He- 

 finds two sections : (1) Eumycena, with smooth spores containing fifty- 

 three species ; and (2) Mycenella, with warted spores, only two species. A 

 complete description is given of each species, with habitat, locality, etc. 

 Spores, basidia, and cystidia of each species are figured. A. L. S. 



Occurrence of an Inverted Hymenium in Agaricus campestris. — 

 This abnormality was noted in cultivated mushrooms, and has beeu 

 investigated by G. Darnell-Smith {Prot. Linn. Soc. N.S. Wales, 191'>^ 



