These basidiomycete, saprobic, white rot fungi are unmistakable, as long as one looks at the underside. They have what appear to be split gills, but are in fact an uninterrupted layer of hymenium (the surface on which the spore producing basidia are formed) that is folded in long pleats. The basidia form between the narrow pleats, which open during rainy periods (when fully hydrated) to release the spores, and close (when dehydrated) during dry times. But even during dry spells it is clearly visible to the naked eye that there are parallel surfaces in contact with each other.
Possibly the most interesting thing about Schizophyllum commune, (and possibly the reason why this is not only the most common but the most widespread fungi in the world, being found wherever there is wood, and on every continent but Antarctica [which lacks trees of any sort]) is that it has roughly 28,000 sexes, although the meaning of a ‘sex’ is different in the fungal world, being merely a way to prevent self fertilization and genetic stagnation.
I can’t begin to do this topic justice without extensive plagiarism, so see Tom Volk’s article for a fuller explanation. But, in a nutshell, the compatibility of any two gametes is determined by having different loci on the nucleus, and different alleles on the locus and Split Gills have over 300 alleles at locus A, and over 90 alleles at locus B, resulting in 28,000 different sexes, and an incredible amount of genetic diversity, with it’s concomitant adaptability.
As far as human usages of this fungi, it is widely eaten in tropical parts of the world, but, due to its small size and tough texture, it is not used as food in North America. This is probably for the best, because it has been found to be an etiological agent for several different diseases, including respiratory infections, brain abscesses, meningitis, eye infections, palate ulceration, and onychomycosis. It’s spores have even germinated on and in people and produced mycelium (according to the aforementioned Tom Volk, in one case it even produced fruiting bodies within the sinuses of a child)! But, on the plus side, it has been utilized as a methanol producer, and some of its metabolites have antibacterial and anti cancer properties.
Since Schizophyllum commune are saprobes that usually feed on dead wood (in fact I don’t remember ever seeing them on something that wasn’t decorticated, as well as dead), I was somewhat surprised to find these on what seems to be a healthy tree in the corner of a hospital parking lot where I frequently kill time waiting for clients. I’ll be checking it out next spring to see if the Split Gills know something I don’t, or whether they are parasitizing this tree. Either way it’s not a good thing for the tree, but it was a great thing for me.
Description-Small (usually 1.5” or less in width) hairy, grey and light grey banded mushrooms, that are usually in tiered ranks, and have pinkish grey, folded hymenium that appear to be split gills; the margin is almost always curved under to the ventral surface.
Similar species-Though superficial dorsal appearances may be similar amongst several otherpleurotoid mushrooms, there are no other Schizophyllum in our region, and nothing else has the split ‘gills’.
Habitat– Usually on dead and dying deciduous logs and snags, but also found on lumber, and occasionally on living trees.
Range-Found on every continent except Antarctica; region wide in appropriate habitat
Reproductive timing-Spores are released during the rainy season, but the fruiting bodies persist year around.
Eaten by– I can’t find anything specific for this species, but probably eaten by all of the usual suspects, including but not limited to, larvae of flies in the families Platypezidae, Mycetophilidae, and Phoridae; springtails in the order Entomobryomorpha, as well as many other collembolans; probably also consumed by slugs, snails, and some beetles in the families Leiodidae, Staphylinidae, Endomychidae, Tenebrionidae, and Erotylidae amongst others; and small mammalian herbivores.
Etymology of names–Schizophyllum is from the Greek words for ‘split leaves’, and refers to the split ‘gills’ of the fruiting bodies. The specific epithet commune is from the Latin word for ‘common’, referring to both its range and to the frequency with which it is found.