FUNGI. 319 
Hyphomycetes are however somewhat indefinite. 
It is indeed doubtful how many of them are auto- 
nomous. Numerous forms are truly polymorphic, 
appearing under different phases; so that what 
were formerly regarded as good ‘and distinct 
species are now found to be in reality only con- 
ditions or immature stages of other forms. The 
fifth order, called Physomycetes, is distinguished by 
“its stalked sacs containing numerous spores or 
sporidia. It is the smallest of all the orders num- 
bering only a dozen British genera, and about two 
dozen species. The black felty cellar-fungus, and 
the grey mucor or mould on preserves are familiar 
illustrations of this order. The sixth and last order 
is that of the Ascomycetes or asci-bearing fungi, 
whose spores, generally eight in number, are pro- 
duced in the interior of groups of elongated sacs 
or thece contained in fleshy, leathery, or wart-like 
fructification. These fungi, of which the morel, 
truffle, and vine disease are well-known examples, 
numbering in this country about a thousand dif- 
ferent kinds, resemble lichens in every respect ex- 
cept that they are produced on decaying sub- 
stances, and are possessed of a mycelium or spawn 
destitute of the green cellular matter of lichens. 
By some authors, such as Schleiden, they are in- 
cluded among the lichens notwithstanding these 
discrepancies, The accompanying illustration of 
