2 MICROSCOPIC PLANTS. [CHAP. 
means of obtaining these low forms of vegetation is 
to collect a quantity of Duckweed, “the green mantle 
of the standing pool,” from the surface of a stagnant 
pond, together with some of the water. If a singie 
plant of Duckweed be put on a glass slip and covered 
with the thin glass used for the purpose, then placed 
under the microscope, a number of distinct forms will 
be seen—some vegetable, some animal. With the 
latter we have nothing to do in the present volume; 
we shall simply ignore them. 
Most of the minute plants found in ponds belong 
to the same tribe as the Seaweeds (the A/g@), but 
we shall also have something to say of the tiny re- 
presentatives of the Mushroom family (the Fungz), 
low forms of which abound on all decaying sub- 
stances. 
One of the simplest of the Alow#—and one of the 
most plentiful—is the Pvotococcus. Our readers will 
probably be struck with the fact that these very 
small plants have very large names. We hope they 
will not be frightened, for, after all, it is a small 
matter; and when they are learnt, they give us some 
fact about the owner, such as it would take many 
words in English to make clear. In this instance it 
means literally first berry or plani, that is, the simplest 
form of plant. It is found in abundance in ponds, 
ditches, rain-water butts, and in fact wherever water 
accumulates in little pools. It consists of a single 
cell or sac containing a jelly-like substance called 
protoplasm, It is this protoplasm which constitutes 
the living part of the plant; the covering (cell) can- 
not grow, it requires to be added to by the proto- 
