28 THE NORTHERN MICROSCOPIST. 
dines, to which the previous fungus also belongs. Its vegetative 
system consists of a colorless creeping mycelium, upon which are 
set short alternate branches, each of which bears a colorless globose 
spore. It is common on decaying leaves; we have also observed 
it on cotton fabrics, and it has several times cropped up during our 
experiments upon animal substances. 
The next is a very common mould indeed: it is of the same 
order as the foregoing, and is named Penicillium crustaceum. ‘This 
fungus is shown at fig. 4 and is that which produces the blue 
mould upon our preserve pots. The spore-chains form brush-like 
heads to the aerial hyphze, the sporidia are globose, and of the 
color of verdigris. These sporidia are able to multiply by bud- 
ding when placed in a suitable liquid, producing at the same 
time a fermentative change. This is not peculiar to Penicillium ; 
Mucor spores, with those of Ascophora, Aspergillus, Papulaspora, 
and others, will produce the same effect. 
There is another species of Penicillium, figured at 2, and known 
as P. chartarum, which possesses oblong pale olive spores. It was 
found upon wall-paper in company with various other fungi. Most 
of the species of Penicillium are very common, some of them are 
sure to spring up in almost every experiment however carefully 
conducted, and so hardy are they and so prolific, that they often 
threaten to annihilate the smaller number of less hardy fungi which 
may happen to be under cultivation. 
At m and z are shown two species of Aspergillus: the A. glaucus 
at m, with its scarcely perceptible septate hyphz and glaucous- 
green heads of sporidia, and the A. vosews, which is delineated at 
m, differing from the former in that it is rather rare, and the head 
of spores being of a rose-red color. It is found on damp paper, 
lint, old carpet, cotton goods, and similar substances. 
The A. glaucus is a very common fungus and is most interesting, 
seeing that its two kinds of fruit may be so easily studied. The 
one kind are sporidia, produced (so far as we know at present) by 
an asexual process, and borne upon the tips of aerial hyphz, at 
which point the receptacle is swollen out, so that the fertile stem 
appears a spherical mass of closely compacted spores. ‘The other 
kind of fruit is of a more perfect character, produced by a sexual 
process. It was formerly called Lurotium herbariorum, and is far 
from rare. Even the casual observer must have noticed the yellow 
spots which often appear on neglected loaves of bread, especially 
if they have been cut open. Every one of these minute spheres is 
really the perfect or sexual fruit of A. g/aucus, the spheres are the 
bright yellow reticulated perithecia, which are closely packed with 
the asci or spore-sacs containing the spores. 
Rhinotrichum lanosum, the last of the Mucedines, is shown at d, 
and was first found on damp wall paper. It forms dense woolly 
