22 
The other has not long been identified. Owing to its extreme 
minuteness, and the depth to which it is sunk in the thallus, it for 
the most part escaped notice, while in the few cases in which it 
was obvious enough to attract attention, its nature was misappre- 
hended. ‘Tulasne was the first to find it in many plants, to suggest 
its importance, and to give it aname. The sfermogonium, as this 
organ is called, is a tiny sac either sunk in the thallus to its very 
summit, or nearly so. Its boundary wall is formed of a very fine 
tissue of interlacing filaments, and on its inner face project a 
multitude of very minute elongated cells either simple or jointed. 
From the ends of each cell, or from each joint, a still more minute 
cell buds out, which, when mature, separates from its parent and 
falls into the internal cavity, where it mingles with the myriads of 
other similar cells produced in the same way. 
These tiny cells, or ssermazia, are so minute that it would take 
a thousand of the longest placed end to end to reach an inch, 
while it would need eight times as many of the smallest ; and as to 
their breadth, many of them are only the fifty-thousandth part of 
an inch across. 
But we must say a few words about the apothecium, in whose 
interior are produced the spores, which, when mature, are capable 
of reproducing new individuals. In order to examine it under the 
microscope, it is necessary to cut a very thin slice vertically. From 
such a slice the structure of the whole and the relation of its parts 
may be clearly made out. 
The base and sides are made up of a tissue which, varying much 
in different species and genera, is evidently of the same origin and 
function in all. From the upper part of the basal tissue a large 
number of filaments grow out parallel to each other and fill the 
whole space within the border, their upper ends forming the disc 
of the apothecium as viewed from above. Lying between the 
filaments just mentioned are a number of larger cells, also springing 
out of the basal tissue, and in these, which are called asc, the 
spores are produced. 
Although all apothecia are composed of the same simple 
elements, there are such numerous differences of detail, that in no 
