The male and female gametophytes are pollen and embryo sacs respectively. I wondered if they are spores as their brethren are meiospores.
But close. Very close. Basically, a gametophyte is a spore that has / is undergoing mitotic division. Therefore, it is still haploid, having not undergone fertilization yet, but it is no longer a dormant, unicellular spore; it's passed into the new phase of gametophyte.
The gametophyte produces sexual organs which produce the gametes that will actually be used in fertilization. Two gametes fuse, at which point, a diploid cell is produced (called a zygote, just as in animals).
The meiospores are the spores you see in the picture on the far left: they are dormant, unicellular, haploid spores, which will turn into the gametophytes. (meio + spores; spores that have undergone meiosis)