| The spore-containing capsule and its stalk or
seta together make up the sporophyte generation of a
moss or liverwort. The sporophyte arises from sexual reproduction
of the gametophyte "parent" (or parents) and remains attached
to the gametophyte. |
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The picture on the left shows two capsules of the moss Bryum caespiticium.
The capsules contain very many tiny spores, each of which is capable
of developing into a new plant. The capsule is usually (as in this
case) borne on a stalk or seta, which elongates (in mosses) as the
capsule ripens. |
| The next picture shows a capsule of the moss Schistidium apocarpum,
with the operculum partly detached. The peristome teeth in this species
are particularly long, and can be seen between the operculum and the
capsule mouth. Notice also that the seta is very short in this species
so that the capsule remains immersed amongst the leaves. |
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The picture on the left shows a capsule of Polytrichum commune,
in which the operculum has detached, and the peristome teeth (small
in this case) are clearly visible. |
| The capsules of liverworts (right) are simpler in structure
than those of mosses, consisting usually of a simple sphere which
releases spores by splitting longitudinally into four sections. In
liverworts, the seta only elongates when the capsule is ripe, and
the rate of elongation is relatively rapid (the photograph shows a
ripe liverwort capsule with a seta in the process of elongation).
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