THE STRUCTURE OF FERNS. 
The ferns form a group of acrogenous plants that is, 
flowerless plants having stems and leaves readily dis- 
tinguishable which are furnished with a caudex or stem, 
from which stem issue leaf-like fronds, bearing their 
peculiar fructification usually at their back, but sometimes 
on their margin. They bear no flowers in the popular 
sense, but instead of them certain very peculiar bodies 
called spore-cases, which contain spores or germinating 
atoms somewhat analogous to the seeds of flowering plant*. 
The external parts of ferns are the following ; namely, 
the root, the caudex, the frond, and the fructification, and 
these are technically called their external organs. 
The true ROOTS consist of fibres, which are either pro- 
duced at intervals along the creeping caudex, or where the 
caudex is not of this creeping habit, they push out on all 
sides from among the bases of the decayed fronds, of which, 
in fact the caudex is constituted. These roots are more or 
less wiry in their texture, sometimes simple, sometimes 
branched, and in many cases, especially on the younger 
portions, are clothed with fine hairs or scales. These organs, 
of course, act as absorbents to supply food to the plants. 
The CAUDEX, sometimes called the rhizome or rootstock, 
is often erroneously regarded as the root It is, however, 
a kind of stem, and assumes, in the case of ferns, two very 
distinct appearances. Sometimes it becomes lengthened 
and creeping, either beneath or upon the surface of the 
soil or rock on which it grows ; and sometimes it is scarcely 
or not at all lengthened, but erect aud tufted, forming little 
