Here's a pretty image of a fern. Have you ever seen a fern like this one? No question about it, this fern is pretty small, about the same size as a neatly trimmed nail on your little finger, and at that size, a fern can be over looked pretty easily.
You may think that this fern doesn't look very fern-like, but in this you are wrong. Your experience with ferns is just too limited. Granted this fern has no ferny fronds, and no vascular tissue either, but I assure you it is quite typical. The most interesting thing about this fern is that it is haploid. The nucleus in each of its cells has only a single set of chromosomes. All of the ferns with which you are familiar have two sets of chromosomes. And what a difference this makes.
This haploid fern is the sexual phase of its life cycle. It makes sex cells, eggs and sperm, and after fertilization, it nutures, for a short while, an embryonic fern, which can grow into a typical appearing fern. So this haploid fern is not some strange, exotic beast, but just the alternate phase of the fern life cycle, the gametophyte phase, the gamete (sex cell) producing plant. Like all other vascular land plants, the familiar fern is the diploid phase, the sporophyte phase, the spore producing plant. And with that I am off to sow some spores and raise some haploid ferns.