- 
636 THE SMALLER FUNGI. 
viands, and which are so bright and vivid in color that they 
at once attract the attention, the most alarming and insidious 
requiring the higher powers of the microscope, and under 
their almost invisibility working signal destruction. Like 
the coniomycetes, or dust-fungi, which we have noticed, the 
hyphomycetes or thread-fungi, and the mucedines or true 
moulds, which are included, are provided with a vegetative 
system of branching threads, called the mycelium, but un- 
like the former, these have fertile or spore-bearing threads 
which are perfectly distinct. These latter kinds are “some- 
times simple and sometimes branched; they may be articu- 
lated or without articulations; short or long, erect or creep- 
ing; transparent or whitish, mostly free from color, and are 
not coated with a distinct membrane. The spores are gener- 
ally simple, sometimes solitary, at others in pairs or strung 
together like beads for a necklace. Amongst all this variety 
of arrangement there is order, for these are but features, or 
partly the features of the different genera of which the Mu- 
cedines are composed. One of the genera is termed Perono- 
spora, known by its having for the most part inarticulate or 
jointless threads and two kinds of spores, one kind on the 
tips of the branches, the other, larger and globose, on the 
creeping mycelium or spawn. The diseases of many of the 
most valuable farm crops, are in Europe and England attrib- 
uted to the several species of the Peronospora, and are called 
the dock, lettuce, onion, parsnip, potato, rose, spinach, and 
tare or vetch moulds; each so specifically distinct as to ibe 
recognized on whatever plant may foster it, and destructive 
and dangerous. Whether the same kinds, or indeed whether 
the peronospora injuriously affects the same vegetables in 
this country, observation and research at present only can 
decide. Its effects in the potato disease are considered in a 
_ paper in a previous issue of the Narurauist. I only know 
that I have met with a similar mould on decaying Agarics, 
strongly resembling Caspary’s figures, and to which allusion 
has before been made. In like manner the “white mildews 
