Here's the breakdown:

* Gametophytes are the haploid (having one set of chromosomes) generation of plants that produce gametes (sex cells).

* Sporophytes are the diploid (having two sets of chromosomes) generation of plants that produce spores.

The life cycle of plants alternates between these two generations:

1. Gametophyte generation: The gametophyte produces gametes (sperm and egg) through mitosis.

2. Fertilization: Sperm and egg fuse, forming a diploid zygote.

3. Sporophyte generation: The zygote develops into a sporophyte, which produces spores through meiosis.

4. Spore germination: The spores germinate and develop into new gametophytes, starting the cycle again.

So, gametophytes are the source of the sporophyte generation. The sporophyte is the dominant generation in vascular plants (like ferns, gymnosperms, and angiosperms), while the gametophyte is relatively small and dependent on the sporophyte.