Special M orphology and Classification. 273 
tinct on the ground of the nature of their spores, must now 
be regarded as different forms of the same plant. Thus, for 
example, the mycelium of the Peronosporeze produces first 
conidia and afterwards oospheres. From the germination of 
the zygospore of RAzzopus nigricans a germinating filament 
arises, which developes directly into a number of sporangio- 
phores ; when its spores (conidia) germinate on a suitable 
substratum, a mycelium is produced on which arise first 
zygospores, and subsequently sporangiophores around these. 
From the mycelium of Mucor Mucedo are developed first of 
all vigorous receptacles with terminal sporangia; the same 
mycelium frequently puts up at a later period receptacles 
with a great number of small sporangia, sometimes called 
sporangioles, which contain only two or a small number of 
spores ; and this form is described by some under the names 
Thamnidium elegans and Ascophora elegans. 
According to some authorities again, beer- 
yeast, Saccharomyces (Torula) Cerevisie, is 
developed in wort from the spores of the same 
Mucor; while others, with greater probability, 
regard it as an independent organism. 
The most familiar instance of this alter- 
nation of generations occurs in some Ure- 
dineze, as in the common ‘rust’ of corn, Be 
Puccinia graminis. The resting-spores of 4 -e\\/} 
this Fungus produce on germination a pro- asa) 
mycelium which bears three or four sporidia 
(Fig. 407) ; these produce first spermogonia 
(Fig. 406), then cup-shaped organs which 
were at one time described as a distinct F'6 407-—Pxecinia 
graniints ; a@ ger- 
species under the name -4Acaitum. The @cf- minating ' teleuto. 
§ spore with a _pro- 
diospores formed in these organs give rise mycelium from 
to resting-spores (teleutospores, which again Rige Toate ie 
either originate the whole series afresh, or fat 
produce the wredospores, out of which nothing but fresh uredo- 
spores arise. The form of the Uredinex which produces the 
‘> 
