CRYPTOGAMIC PLANTS. 93 
and ceases to shine as soon as the sun rises. 
The same author says that he never saw the 
Agaricus olearius shine during the daytime, how- 
ever dark the room in which it was kept ; and we 
might remark upon this that fungi only vegetate 
at night. But M. Fabre has, more recently, ob- 
served that the phosphorescence of this agaric 1s 
not intermittent, as M. Delille supposes, and that 
it shines during the day as well as by night. Kx- 
posure of the plant to sunlight appears to have no 
influence whatever upon the phenomenon, “ and 
does not prevent its manifestation as soon as 
the fungus is removed into a dark place.” ‘This 
seems, however, to indicate that the sun’s heht 
has, in reality, an influence upon the emission of 
light by this fungus during the daytime, and 
that the phenomenon observed by M. Fabre is 
probably a case of phosphorescence after msola- 
tion—a circumstance not to be passed over slightly, 
as we see further on, that a similar fact has been 
observed in the insect world. 
M. Fabre has also shown that the dampness or 
dryness of the air does not appear to have any 
influence upon the phosphorescence of Agaricus 
olearius, unless indeed the dryness is so intense 
as to desiccate the tissue of the plant. An eleva- 
tion of temperature, within certain limits, does 
not modify the phenomenon: below +9° to +6° 
(centigrade) the light ceases, but the phosphores- 
