DESCRIPTION OF PLATES. 151 
upon the surface of a glass slide we spread a little 
sweetened mucilage, and upon this soil sow the 
seeds of the microscopic plant by gently applying 
the surface to a patch of mould in full fruit, we 
can quickly raise a luxuriant crop, and, under the 
microscope, can watch the development from hour 
to hour. For this purpose the glass slide must be 
kept in amoist atmosphere, and if the temperature 
be somewhat elevated, 90°-100° Fahr., the growth 
will be all the more rapid. The whole process is 
very simple, and consists, in the first place, of the 
outgrowth from the spore of a slender shoot, the 
interior of which is filled with protoplasm con- 
tinuous with that in the spore itself, and being, in 
fact, an extension of this, resulting from the imbi- 
bition of water and of nutrient material. 
In some species this filament continues to grow in 
length and to give off side branches without the 
formation of any septa in the ramifying mycelium 
which results from this mode of growth. In this 
case we have evidently a unicellular plant, notwith- 
standing the linear extension and complicated rami- 
fications which result from the continued growth 
of the plant. 
In other species, transverse septa are developed 
at intervals, and we have a linear series of elonga- 
ted cells originating from the little mass of proto- 
plasm enclosed in the first instance in the cell-wall 
of the oval or spherical spore. 
From this branching mycelium, little upright 
stems or pedicles are given off, and these divide 
at the summit into several slender filaments which 
