FERNS AND MOSSES. 147 
the calyptra, which easily falls off. Underneath it will be seen 
a small rounded lid (operculum), which becomes detached when 
the spores are ripe and allows them to escape, not, however, 
quite at random, for the open mouth of the capsule is guarded 
by an inwardly projecting fringe of pointed brown threads 
constituting the peristome. Sections through a fairly young 
capsule (fig. 61, B) show it to be very complicated in structure, 
but the most important part is a narrow layer of cells by which 
the spores are produced. When these are ripe the other internal 
parts shrivel up and the lid drops off. 
The spores (cp. p. 92) are very minute, and, unlike seeds, are 
single cells. If they fall upon a damp place they grow into a 
branching mass of delicate green filaments, the protonema, upon 
which leafy odphytes are produced as buds. 
OOPHYTE (Gametophyte). 
In many common mosses the buds which are produced on 
protonema grow into either (1) female 
plants, or (2) somewhat smaller male 
plants. 
In a female plant there will be found, at 
the end of the stem, a group of exceedingly [Ys 
minute flask-shaped bodies, the arche- :y, 
gonia. Each archegonium consists of a 2% 
slender neck, the axis of which is occu- 
pied by a row of small canal-cells, and 
of a dilated venter in which the rounded Neem 
egg-cell is contained (fig. 62, c). Above age 
the egg-cell is a minute ventral canal-cell. Fie. 62.—Reproductive Or- 
In a male plant the place of the arche- Ce oy rian 
gonia is taken by a collection of very small zoid (x 240). €. Archego- 
club-shaped antheridia (fig. 62, 4). Within Y°VBC3 592} statics woe 
each antheridium are developed a large  canal-cells of neck; v..c. 
number of spiral antherozoids (fig. 62, B), tal en 
each of which is provided with a couple of 
slender protoplasmic threads at one end, that by their lashing 
movements enable the antherozoid to swim about in the moisture 
which collects on the surface of the moss-plants. 
When an archegonium is ripe, the canal-cells swell up and 
become converted into a sort of mucilage which forces apart the 
cells forming the tip of the neck. At the same time the anthe- 
ridia of neighbouring plants become mature, and part of their 
contents swells up into a jelly by which they are burst so as to 
liberate the antherozoids. These minute motile bodies swarm 
