by no means apparent, and has been
the subject of much discussion.

The first person who threw any light upon the problem, as far as I
have been able to discover, was the well-known geologist, Professor
Morris. It is now thirty-four years since he carefully described and
figured the coin-shaped bodies, or larger sacs, as I have called
them, in a note appended to the famous paper "On the Coal-brookdale
Coal-Field," published at that time, by the present President of
the Geological Society, Mr. Prestwich. With much sagacity, Professor
Morris divined the real nature of these bodies, and boldly
affirmed them to be the spore-cases of a plant allied to the living
club-mosses.

But discovery sometimes makes a long halt; and it is only a few
years since Mr. Carruthers determined the plant (or rather one of the
plants) which produces these spore-cases, by finding the discoidal
sacs still adherent to the leaves of the fossilized cone which
produced them. He gave the name of _Flemingites gracilis_ to the plant
of which the cones form a part. The branches and stem of this plant
are not yet certainly known, but there is no sort of doubt that it was
closely allied to the _Lepidodendron_, the remains of which abound in
the coal formation. The _Lepidodendra_ were shrubs and trees which put
one more in mind of an _Araucaria_ than of any other familiar plant;
and the ends of the fruiting branches were terminated by cones, or
catkins, somewhat like the bodies so named in a fir, or a willow.
These conical fruits, however, did not produce seeds; but the leaves
of which they were composed bore upon their surfaces sacs full of
spores or sporangia, such as those one sees on the under surface of a
bracken leaf. Now, it is these sporangia of the Lepidodendroid plant
_Flemingites_ which were identified by Mr. Carruthers with the free
sporangia described by Professor Morris, which are the same as the
large sacs of which I have spoken. And, more than this, there is
no doubt that the small sacs are the spores, which were originally
contained in the sporangia.

The living club-mosses are, for the most part, insignificant and
creeping herbs, which, superficially, very closely resemble true
mosses, and none of them reach more than two or three feet in height.
But, in their essential structure, they very closely resemble the
earliest Lepidodendroid trees of the coal: their stems and leaves are
similar; so are their cones; and no less like are the s