Pleurotus australis is not the most common of mushrooms and unfortunately it’s habitat overlaps that of the poisonous Omphalotus nidiformis, or ghost mushroom. Thats the one that glows in the dark. I have only ever seen P. australis growing on peppermint trees. That is Agonis flexuosa. The first one I ever saw was in the Perth area. I enlisted the help of a venerable mycologist (Roger Hilton) to identify it. There were a few fruiting bodies on the tree in question and they were huge. The texture of these was like leather and there is no way that they could be eaten. Note the wavy cap margin.
In the region down where I live now, however, the oyster mushrooms are smaller and would be edible if there were enough of them to be bothered with. They also get fly-blown very quickly.
For some further information on locally picked oyster mushrooms, see WhereFishSing.
Here is a picture of some growing at Yeagarup.
They are quite simple to cultivate. The same procedures can be used as one would apply to any other oyster mushroom. Pasteurised straw is a the simplest medium. The rather odd thing about P. australis under cultivation is that it bears little resemblance to the wild fungus. The pinheads are a dark black/purple colour.
When grown on a little further, they are a rather soft mushroom, with a distinctive purple tinge to the upper surface. I have some pictures of these somewhere and when I find them I will add them to this post. Ah, here we go. This is an example of a cultivated one.
12 Years on and here is another picture of a cultivated specimen. In this case I took the culture from a dried specimen. It took a while to take off but grew quite well after that. I fruited this one in my greenhouse whereas the first one was fruited in a rather dark corner of my kitchen. In any case the result was quite different.
One thing that must be said about this mushroom. Be very careful not to confuse it with Omphalotus nidiformis. They are very similar in the wild. O. nidiformis, however, will glow if you break off a small piece and put it in a jar by your bed. The oyster mushroom can also be recognised by the fine network of criss-crossed gills that run right down the stem to the point where it emerges from the tree. This is a picture of Omphalotus nidiformis. It is somewhat variable, but this is typical.
Omphalotus nidiformis from Dorrigo
23 June 2013
This year I visited the site of the mushroom shown in the first illustration. There was a new crop growing and they were in the juvenile stage. As with the local ones from down here, they had a dark purple cap with a slightly scaly texture. They were more robust, but otherwise matched the local specimens. So it is clear that they change as they age. I am now more comfortable with the identification of both as P. australis. I again tried to bring this into culture, but without success this time. I do have some pieces of infected wood though, so I will try to culture those. A friend in Perth got a culture of the Perth specimen going last year, but he found that it would not grow on straw like his normal king oyster mushrooms.
9 May 2021
It is a long time since I updated this post. I have now moved to Busselton. These mushrooms are everywhere around the town and in the adjacent forest particularly this year. If you go out in the evening with a torch you can see them releasing spores. You have to see this in person to appreciate the vast amount of spores that are released by these mushrooms. They must travel a long distance which makes it surprising that they aren’t more common on Peppermint trees in more inland locations. A friend did send me a picture of some on one of his apple trees in Manjimup and they have been spotted on a grape vine in Margaret River however so it seems that they are capable of occurring on other hosts. Actually, now that I think of it, I have seen these on a Warren River Cedar (Taxandria juniperina) while taking a tour along the Donnelly River and Taxandria parviceps(?) near Capel.
The spores are elongated, rather like grains of rice, about 10.5 x 5.6 microns. This is a microscope image showing the spores along with some sizing statistics. These differ from the spores of Omphalotus nidiformis which are close to spherical.
In the wild, this mushroom is often found to be riddled with larvae. These belong to the fungus fly Tapeigaster cinctipes. The males of this species patrol the tops of the mushrooms, waiting to mate with any females that happen along. The females lay their eggs in the gills and the larvae make their way into the mushroom from there. It is common to see these mushrooms pecked to pieces by birds that are no doubt feeding on the larvae. The images below show a male on the top of a mushroom and a view of one of the larvae under the microscope.
