LUMINOSITY. 395 



them of the faculty of giving light." The luminosity 

 of this kind of fungus is well known to miners, and 

 Humboldt, as well as others, have written of it in 

 glowing terms. Different names have been given to 

 different varieties, some of which have occurred in 

 almost all parts of the world of which the lower 

 vegetable productions are known. 



The second group of luminous fungi are those 

 exhibited by perfect and properly-developed species. 

 These are, for the most part, agarics with white 

 spores growing habitually on wood ; and it is a 

 remarkable fact, that although many other kinds 

 with coloured spores grow on wood, all the known 

 luminous species are referred to the same sub- 

 genus {Pleiirohis) in which the stem is eccentric, or 

 obsolete, and the spores white. 



One of the earliest known exotic species {Agaricus 

 Gardncri) was first made known by Mr. Gardner in 

 1840. "One dark night about the beginning of 

 December, while passing along the streets of the 

 Villa de Natividate, Goyaz, Brazil, I observed some 

 boys amusing themselves with some luminous object 

 which I at first supposed to be a kind of large 

 fire-fly ; but, on making inquiry, I found it to be 

 a beautiful phosphorescent species of Agaricus, and 

 was told that it grew abundantly in the neighbour- 

 hood on the decaying fronds of a dwarf palm. The 

 whole plant gives out at night a bright phosphorescent 



