BASIDIOMYCETES.— AGARICUS. 383 
sh. Placed upon and derived from this layer are the densely 
crowded club-shaped cells known respectively as the bastdia, s’, 
s’, 8”, 8’, or paraphyses, q, according as they produce spores 
or remain sterile. 
From each basidium, in this species, two spores are pro- 
duced, the process of their development being as follows :—On 
the free rounded surface of the basidial cell there first appear 
two little processes, s’, which quickly become swollen at their 
extremities, s”. The swelling in each instance increases, and 
finally a protoplasmic cell is produced, s’”’, which becomes 
separated from the little stalk, s’””’, and forms a spore. The 
Fic. 840. 
Fig. 840, Transverse section of a lamella of the mature hymenium of Aga7é- 
cus campestris, t.Trama. sh.Sub-hymeniallayer. q. Paraphyses. 5’, 3", 
s'’, Basidia in different stages of development, showing formation of 
spores. s’’, Basidium after the spores have fallen off. After Sachs. 
spores, thus formed, when placed under favourable circum- 
stances are capable of producing the mycelium, or dense net- 
work of hyphee, from which again the fructification or receptacle 
is developed. Judging from analogy, we would have expected 
the fructification to be the result of a sexual process taking place 
in the mycelium, thus giving rise to an alternation of genera- 
tions, but from the latest researches on the subject this does 
not seem to be the case. 
(iv) Ascomycetes.—From this division of Fungi two examples 
may be selected for description. 
The first which we will consider is Claviceps purpurea, or the 
Ergot Fungus. If we trace the development of this Fungus 
upon the ovary of the affected Grass (Rye being the one more 
