184 THE JOURNAL OF BOTANY 



being most abundant about 12^ C. The effect of various gases 

 was tried : nitrogen, hydrogen, ether vapour and chloroform 

 vapour destroyed the kiminous effect, whereas oxygen causes 

 no change. The hght can be perceived at a distance of at least 

 thirty metres ; it is white and not coloured as it usually is 

 in fungi. Two plates are given showing the morphological 

 characters of the fungus ; a third gives prints of a fern frond 

 and a maple leaf taken by the light of the fungus on a photo- 

 graphic dry plate. The paper is full of biological interest, and is 

 further valuable for comparison with the results obtained by other 

 investigators. — J. R. 



W. O. Gloyer has pubhshed in the Technical Bulletin 44 

 of the New York Experimental Station an account of his 

 investigations on the cause of stem-rot and leaf spot of Clematis. 

 He shows conclusively that the cause of the disease is the fungus 

 AscocJujta clematidijia Thiim. " Considering the variability of the 

 fungus found by the writer, any of the descriptions given for the 

 different species of Ascochyta described on Clematis would in 

 general apply to it " : he therefore emends Thlimen's description 

 to include these forms. Methods of control and prevention of the 

 disease are studied, and the result seems a very sound piece 

 of work. The paper is illustrated by five plates. — J. R. 



Those who study Agaricacese have for some time paid more 

 and more attention to anatomical details, with a view to obtaining 

 facts which will be of use in discriminating between closely allied 

 species, in deciding whether certain species regarded as more or 

 less cosmopolitan are truly so, and for ascertaining whether some 

 of the rarer species are not really forms due to habitat, etc. Any 

 contribution to the unravelling of the systematic points raised by 

 the myriads of fleshy evanescent forms is welcome. Some genera — 

 e. g. Inocybe and Mycena — have been found to show microscopic 

 characters which are exceedingly valuable for differentiating 

 species, and doubtless many others will become much clearer when 

 so treated, though it is not yet apparent what structure will be 

 found of specific value. H. S. Yates in the University of California 

 imhlications in Botayiy (vol. vi, pp. 221-265, 1916), has a paper 

 on the comparative histology of Californian Boletacecd. The 

 investigation deals with six well-defined species ;^ under three of 

 these it has been possible to separate certain definite forms — from 

 Ceriomyces communis four, from C. crassus two and from Suillellus 

 Easticoodece two. The nomenclature adopted is that favoured at 

 New York ; the species would all be placed in the genus Boletus 

 by mycologists in this country. The structures principally 

 studied were the surface and content of pileus and stipe, and the 

 hymenial surface : the details are figured in five plates. The 

 author says : " While at present I am not able to bring forward 

 histological details to separate all the species, it seems probable 

 that this might be possible if the series of species described as to 

 their histology were sufficiently large." What he does seem to 

 have done, more effectively perhaps because unintentionally, is to 

 demonstrate the impossibility of some of Murrill's genera. — J. R. 



