318 FIRST FORMS OF VEGETATION. 
matrix in which they are developed, in the form 
of a minute collection of dust, entirely destitute of 
any covering or receptacle, except that which is 
furnished by the skin of the plant raised around 
them. This class is the most 
destructive of the whole tribe. 
Smut, bunt, and rust, are zoo 
familiarexamples of this most 
notorious class. The fourth 
order is called Hyphomycetes 
or web-like fungi, because the 
spores are free, developed on 
naked filaments whose ter- 
minal cells are often trans- 
formed into a series of spores 
like a row of beads. The 
general appearance of the 
plants belonging to this order 
is that of a quantity of dust- 
like seeds imbedded in a 
flaky cottony substance, like 
aspider’s web. The different 
re Geese eae kinds of common mould, 
)Aungi: beindualaage Hlug, yellow, and green, the 
potato-disease, caterpillar and silkworm blights, 
and various kinds of mildew, are common exam- 
ples of this order. The limits of the genera and 
species belonging to the orders Coniomycetes and 
