HYPODERMI4#.—BASIDIOMYCETES. | 381 
this process may be carried on throughout the summer. But 
towards autumn some of the older uredo-fruits produce what 
are known as the teleuwtospores (figs. 837, t, and 838, t, t). These 
are two-celled, somewhat elongated spores, which, germinating 
upon the Barberry leaf, give rise to the ecidium fruits which 
we have already described. 
It will be noticed that as yet no sexual process has been 
discovered to occur during the life history of Puccinia, Should 
such be hereafter demonstrated, it will probably be found that 
the «xcidia are formed in consequence of the fertilisation of 
female organs by the spermatia. 
Fic. 837. Fic. 838. 
Fig. 837. Part of alayer of uredospores. sh. Hyphe or mycelium ramifying 
among the cells of a leaf of the Couch Grass. u7. Uredospores. ¢. A 
teleutospore. Fig. 838. e. Epidermal, and 6, inner layer of cells of the 
infested leaf. ¢,¢. Teleutospores. After De Bary. 
(iii) Basidiomycetes.—As an example of this group we will 
briefly describe what is known of the life history of the common 
Mushroom (Agaricus campestris). That which is ordinarily known 
as the Mushroom is in reality the receptacle (fig. 6), fructifica- 
tion, or spore-producing structure, growing from a mycelium, my, 
which is vegetating underneath the surface of the ground or 
other substance upon which the fungus may be growing. The 
receptacle, in the case which we are considering, consists of two 
parts (fig. 839, A), viz. :—the cap or pileus, p, and the stalk 
or stipe, st. The former may be regarded as the essential part of 
the receptacle, the spores being produced on its under surface, 
whilst the stalk simply serves the purpose of raising the cap 
some distance above the ground. 
