What is a spore in the reproduction cycle of mosses?

Example : Sphagnum

1. The gametophyte (haploid=n) is the conspicuous generation. Gametophytes bear male organs (antheridia) and female organs (archegonia). The antherozoids (male gametes) require water to swim to an archegonium and fertilize the egg.

2. After fertilization a zygote (2n) develops as a sporophyte, which remains attached to the gametophyte. Each sporophyte may produce a capsule.

3. In the capsule, sporocytes (2n) undergo meiosis to produce spores (n) arranged in tetrads (groups of 4 spores), that eventually split up into single grains. These grains keep a trilete (3-slit) mark.

4. When mature, the spores are ejected from the capsule. They germinate on the ground and form a protonema, then a new gametophyte.