AUGUST. 
249 
The two former of these groups are comparatively small, while the 
latter embraces by far the larger number of the Ferns known either to the 
botanist or the cultivator. Some persons, indeed, exclude the two minor 
groups from among the true Ferns, which they consider to embrace only 
the Polypodiaceae ; but for our present purpose, the common notion, 
which regards them all as Ferns, is preferable. 
The Ophioglossaceae and Marattiaceae are distinguished technically 
from the Polypodiaceae by the nature or structure of their spore-cases, 
and the Polypodiaceae are themselves separated into minor groups chiefly 
by the mode in which the spore-cases are arranged, aided by certain 
secondary modifications of their form. Hence, it becomes essential, 
as a first step in the inquiry, to understand what is meant by a spore- 
case. The answer to this inquiry will lay the foundation upon which all 
the more refined distinctions between families and groups of families 
are based. 
From the rhizome or caudex, two forms of stem which occur 
among the Ferns, proceed downwards the roots and upwards the leaves, 
as is the case in other plants. The term frond has long been, and is 
still, commonly used for the parts in Ferns which are analogous to the 
leaves in flowering plants, and it is conveniently retained to express the 
fact that the two are not quite identical in character. The frond of the 
Fern differs from the leaf of the flowering plant in this, that it actually 
bears on its surface the parts known as the fructification, which the true 
leaf does not. This is the popular view. In a strictly physiological 
point of view, perhaps, the difference does not exist, inasmuch as the 
so-called “ fructification ” in Ferns is not strictly analogous to the fruc¬ 
tification of a flowering plant, but is rather to be considered as analogous 
to the little buds or bulbils which some plants throw out from their 
surface. Be this as it may, the frond of the Fern bears on some part 
of its surface, usually the under side, sometimes the margin, 
rarely the upper side, what is called the fructification. This 
fructification consists of clusters or lines of minute bodies, usually of 
a dark brown colour, and usually, as already stated, placed on the under 
surface of the frond, or that which is exterior to the axis of develop¬ 
ment. These minute bodies, if examined with a magnifier, will be seen 
to be roundish, and they will be found to be hollow; for if they are 
quite mature, some of them will be seen to have burst on one side, and 
to consist of two concave portions, held together by a kind of jointed 
ligament, attached along the other side, at least this would be the 
appearance presented in the majority of the Polypodiaceae. If brushed 
from the frond on to a sheet of white paper, these small bodies would 
have the appearance of tolerably fine particles of dust or sand ; so fine, 
indeed, that the naked eye would not readily make out their true 
character. They, however, are the all-important spore-cases, which 
determine what name the Fern is to bear. Their contents, infinitely 
smaller and scarcely visible, even with a tolerably good magnifier, are 
the spores, from which new plants are raised. 
We shall next have to inquire what these spore-cases indicate ; that 
is to say, how they are applied to the purposes of classification. 
Chelsea . Thomas Moore. 
