23 
Tribe Cyaxhee^.— Treefern. With large fronds ; tbe spore-cases 
with a more or less oblique ring, in globular sori on tbe under surface 
of the fronds. For an example see the cmnmoii tree ferns, Ahopfiila. 
Tribe PoLY’PoniEiE, — Spore-cases wnth a longitudinal or scarcely 
oblique ring, numerous and atipitate (stalked) in sori or patches on 
the under side or rarely the margins of the fronds. This tribe is 
divided into two divisions: — (A.) Sori covered, at least when young, 
with an iiulusium. Examples: Woolly Tree Fern, Hare’s-foot Fern, 
Grass-leaved Fern, Maidenhair Fern, Bracken, &c. (B.) No indusium. 
Examples : The Folypodiims^ Stag’s-born and Elk*s-horn Ferns. 
Fern Structure and Sexual Development. 
Probably no class of plants are such general favourites as ferns ; 
therefore a few words as to the botanical names of their various parts 
may be here given. 
The Moots proper of ferns are entirely fibrous, often rigid and 
wiry ; when young, often covered with soft hairs. 
The Stem is spoken of under difiierent terms, as rootstock^ 
rhizome^ and caudex^ this latter being usually applied to the stem 
when above ground, whether in tbe form of a tree-trunk or resembling 
tbe stem of a trailer or climber, the term rhizome being applied to 
the underground stem ; in some of these latter, beneath the crown are 
formed a number of brittle roots resembling the tubers of a Dahlia. 
The Leaves are termed fronds, and their vernation, with few 
exceptions (the Adder-tongues and their allies), circmate (coiled). 
The stalk from the rhizome to the lamina or ramification is called the 
stipes j its continuation through the ramification of a compound frond 
is termed the rliachis ; pinna and pinnule being used for leaflets as in 
other plants. 
The Fructyication is borne upon the back, edge, or on a separate 
frond or portion of frond. The clusters of fructification are called 
sori^ and tbe part to which these are attached the receptacle. The 
sori is a cluster of sporangia or spore-cases, and may he naked, as in 
Molypodhim^ or covered with an indusium^ as in Asplenium^ and nearly 
flat, tubular, or funnel-shaped, as in Trichomanes. The spore-cases or 
sporangia in most cases arc one-celled, and more or less surrounded 
with a jointed ring or annulus. These spore-cases are stalked or 
stalkless (sessile), and the ring is vertical or transverse, according to 
the tribe or sub-order to \vhich the plant belongs. 
Germination. — The spores of some ferns take a longer time than 
others to germinate after leaving the sporangia. The first stage of 
their growth is the formation of what is known as the protliallus. 
This is usually somewhat reniform in shape, and composed of cellular 
tissue. On the under surface are two sorts of organs analogous to 
the stamens and pistils of flowering plants ; these are respectively 
known as antheridia and archeqonia. The position of these organs has 
been found to vary in different tribes. 
Antheridia. — These are small masses of tissue developed in the 
same manner as the root-haira, consisting of a single layer of cells 
forming the wall and containing a number of spirally coiled threads, 
usually with a number of cilia on their anterior coils. At maturity 
the aiitheridium swells by the absorption of water, and finally bursts 
its wall, discharging these coiled filaments, which possess the power 
