1893.] 



Action of Light on Bacillus anthracis. 



39 



otherwise destroy the reserve substance by 'promoting its rapid oxida- 

 tion. 



Colours of Fungi. 



One of the most interesting cases for our purpose is the colours of 

 the spores of Fungi.* I find very little information as to the correla- 

 tion between the habits of Fungi and the colour of their spores ; but 

 a somewhat hurried examination of the matter has yielded the follow- 

 ing information : — 



Taking the higher Hymenomycetes first, since more attention has 

 been paid to the colour of their spores, as is well known, the large 

 genus of Agaricus is usually broken up into five groups, according to 

 the prevailing colour of the basidio-spores. I confine myself to the 

 British species. 



Of the white-spored Agarics (Leucospori) I find that Stevensont 

 mentions about 400, and of these the vast majority are found in 

 woods, and many of those occurring in pastures seem to me to be 

 probably well sheltered by the herbage. CookJ notices that they are 

 in contrast with the dark-spored groups in not growing on dung or 

 in rank places. 



As regards the next set, the Hyporhodii or pink-spored forms, it 

 appears not without significance that, while some grow in open 

 woods, about two-thirds are found in more exposed situations. Mr. 

 Plowright was under the impression that the spores of these Hypo- 

 rhodii germinate easily ; if this is so the fact is significant. 



The Dermini, with yellowish to clay-coloured spores, present mixed 

 features ; it seems to me that not quite half grow in more or less 

 woodland places, often very open, while a little more than half grow 

 in more exposed situations. It must be noted, however, that the 

 colours of the spores in this group vary more as to shade than in any 

 of the others. 



The fourth group of Agarics are the Pratelli, with spores of very 

 various shades of purple tinged with black or with fuscous hues, 

 and passing into brown, violet, slaty, and even pink hues. The 

 majority by far grow in exposed places. 



There is a curious remark in Stevenson, regarding these Pratelli : 

 " It is to be observed that the spores vary in colour according to the 

 colour of the ground on which they are deposited." This seems 

 clearly to indicate that these spores respond to the kind of light 

 they receive, and seems worth pursuing further. 



Lastly, we have the black-spored Coprinarii, none of which are 



* Elfving {loc. cit., p. 53) suggests that the coloured pilens of some Hymeno- 

 mycetes may act as colour-screens, and the matter wants investigation, 

 f ' Hymenomycetes Britannici,' 1886. 

 X ' Handbook of British Fungi,' vol. 1, p. 5. 



