After collecting and germinating the spores into mycelium, they were able to get individuals from all over the world to mate with one another. As long as two strains are of different mating types they are able to mate and form fertile offspring. In order to understand something about sex in fungi, we need to look at the general nuclear cycle of fungi. Comparing this to the life cycle of an animal or plant you'll notice some big differences. For the most part fungi are either haploid, with one set of chromosomes in a nucleus, or dikaryotic, with two sets of chromosome, each set in a separate nucleus.
Most animals are diploid, with two sets of chromosomes in a single nucleus.
In most fungi the diploid consists of only a single cell in the life cycle. There are four phyla of fungi , each of which is distinguished by its sexual reproductive structures and the amount of time spent in each of the phases. It doesn't sound very romantic in a Valentine's Day month, but sex in fungi primarily involves getting the two parental nuclei into the same cytoplasm. Wherever they touch they can exchange nuclei. Many of the more primitive fungi have only two sexes.