48 OUTLINES OF BKTTISII FUNGOLOGY. 



is one of the most remarkable phenomena amongst Fungi, 

 and without example amongst other plants. It sometimes, 

 hoM'ever, proceeds from a mycelium, and in the end always 

 gives rise to fruit-cells, and sometimes to spiral tissue, and 

 is therefore by itself no sufficient reason for excluding these 

 productions from the rank of vegetables. 



The colour of Fungi depends in most cases upon the eon- 

 tents of the cells, except in those instances where the walls of 

 the cells themselves are carbonized. These contents are of 

 almost every colour except a pure green. When green occurs 

 in Fungi, as in Peziza (Bruginosa, Agaricus ceniginosiis, etc., 

 yt is generally of a metallic hue, or dull and inclined to olive, 

 as in the green Russules. 



I notice, in conclusion, under this head, one or two pro- 

 perties occasionally exhibited by Fungi. The most notable 

 of these is the luminosity of some species. Agaricus olearius, 

 for instance, which grows on olive-trees in the south of 

 France, is so luminous that it is possible to distinguish letters 

 by its light, and still more luminous species have been found 

 in Brazil, Australia, and Amboyna. We are not, however, 

 without luminous Fungi in this country, but the pheno- 

 menon is rare, and has been observed principally in imper- 

 fectly developed species. Decayed wood and leaves also are 

 sometimes luminous, but whether from the presence of fun- 

 gous matter or not, is not quite certain. 



I am not aware that in these cases there is any accession 

 of heat, but Dutrochet has observed that more heat is gene- 

 rated by Boletus- cenetis occasionally than by any other vege- 

 table. 



It has been asserted that powerful odours are destructive 

 to Fungi, and especially that of Russian leather; but I do 

 not find this confirmed by my own experience, at any rate as 

 far as regards the instance alleged. 



