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the bark or tissues of the plant on which they grow; in other 
cases the spores are produced without any covering whatever. 
I have before remarked that Fungi have been up to a late period 
divided into two grand sets, according to the way in which their 
fruit is produced, either naked on the tips of threads or within 
little sacs called asci. The group I am now treating of comes 
under the first set, whose spores are on the tips of threads called 
basidia ; but Fries long ago remarked that many errors in 
systematic arrangement arose from attending too much to micros- 
copical characters and not sufficiently to those of structure and 
development. Affinity, he says, is to be considered first, then 
character. Thus he considers that certain species bearing naked 
spores cannot be separated from others whose fruit is contained in 
asci, merely on that account without regard to their similarity in 
point of growth and structure; and he adds, in corroboration of 
his views, that it is impossibile to separate species closely related 
by morphology and history, when he finds that, in certain cases» 
the spores have become naked from absorption or disappearance 
of the asci, in which at one or other period of their growth they 
were enclosed. For instance, speaking of Chetomium, a 
pretty little Fungus common on damp paper, he says, if it 
be examined when moist the asci will not be seen, but 
that they are evident enough when the plant is dry, and 
even now, with our improved microscopes, if we examine this 
plant when quite mature, or rather gone by, we shall find that the 
asci have been absorbed, and we should be disposed to place it 
among the naked-spored group, Coniomycetes, unless, guided by 
its morphology and affinity, we should perceive its true relation- 
tionship, and place it amongst the Ascomycetes, which is its true 
position. Fries includes in his family, Pyrenomycetes, such Fungi 
as produce their fruit, whether naked or in asci, within proper 
closed conceptacles or perithecia, where we see that he pays little 
attention to the character of what is called endosporous or exos- 
porous fruit-formation. Typically, says Fries, the Pyrenomycetes 
