122 FUNGI. 
tions which the form and colour of the spores undergo in dif- 
ferent species, as this has already been alluded to. The spores 
Fia. 46*,—(a) Spore of Gomphidius Fic. 47.—Spores of (a) Polyporus cesius ; 
viscidus; (6) spore of Coprinus micaceus. (v) Boletus parasiticus ; (c) Hydnum. 
in the Polyporei, Hydnei, &c., are less variable, of a similar 
character, as in all the Hymenomycetes, except perhaps the 
Tremellini. 
When an Agaric is mature, if the stem is cut off close to the 
gills, and the pileus inverted, with the gills downwards on a 
sheet of black paper (one of the pale-spored species is best for 
this purpose), and left for a few hours, or all night, in that 
position, the paper will be found imprinted in the morning 
with a likeness of the under side of the pileus with its radiating 
gills, the spores having been thrown down upon the paper in 
such profusion, from the hymenium, and in greater numbers 
from the opposed surfaces of the gills, This little experiment 
will be instructive in two or three points. It will illustrate the 
facility with which the spores are disseminated, the immense 
number in which they are produced, and the adaptability of the 
gill structure to the economy of space, and the development of 
the largest number of basidiospores from a given surface. The 
tubes or pores in Polyporei, the spines in Hydnei, are modifica- 
tions of the same principles, producing a like result. 
In the Gasteromycetes the spores are produced in many cases, 
probably in most, if not all, at the tips of sporophores ; but the 
hymenium, instead of being exposed, as in the Hymenomycetes, is 
enclosed within an outer peridium or sac, which is sometimes 
double. The majority of these spores are globose in form, some 
of them extremely minute, variously coloured, often dark, nearly 
black, and either externally smooth or echinulate. In some 
genera, as Enerthenema, Badhamia, &c., a definite number of 
spores are ai first enclosed in delicate cysts, but these are excep- 
