Ghost Fungus: the sequel

Omphalotus nidiformis at twilight. Click to enlarge.

Last year I wrote about the cluster of bioluminescent Ghost Fungus (Omphalotus nidiformis) growing on a dead tree in the backyard of the house where I live (see Glow-in-the-dark fungi). This year we had an exceptionally wet March creating great conditions for fungi of all sorts. And guess what — those ‘ghosts’ were back in droves! But strangely, I didn’t recognise them at first.

The first thing I noticed was a troop of little yellow buttons coming out of the wood, developing into brown funnel-shaped mushrooms with yellow gills. They were much darker than the white Omphalotus that grew on the same tree the previous year and I assumed I had a different species sending up fruiting bodies. (‘Fruiting body’ just means the visible, spore-producing part of any fungus, as opposed to the usually unseen network of filaments or mycelia beneath the surface.) I cut one of the caps off and tried to take a spore print, but hardly any spores came out onto the paper. It was just enough to see the spores were white.

Several online sources mention a dark form of Omphalotus nidiformis, which doesn’t glow as brightly as the light form (ref. Miller, 1994). It dawned on me that’s what these might be. I turned off all the lights and went outside at night and sure enough, some of them glowed faintly. In addition, there were a few freshly emerged paler fruiting bodies that I hadn’t noticed in the daytime, luminescing brightly.

My work took me away from home for the next four days. When I returned, I was astonished to find the backyard had practically become a Ghost Fungus forest! The familiar white clusters had appeared around the bases of nine dead and living trees and they were starting to spread into next door’s backyard too. The brown ones had grown into 20-cm-wide caps with undulate margins and turned creamy white on the edges, though overall they were still darker than the ones which had since appeared.

Dark form of O. nidiformis on 26th March.

The same cluster on 30th March.

At night the sight was magical. The luminescence jumped out the moment I turned the torch off and I felt myself quietly gasp in awe. I urged friends to drop by and see the display; they were as captivated as I was.

It’s hard to put into words why these dimly glowing shapes elicit such wonder. After all, compared to the bright lights in our cities and towns which most of us see daily, the light from a glowing mushroom is faint and insipid. But in the darkness of an unlit forest it’s utterly radical. There’s something about nature that heightens our senses.

Omphalotus nidiformis is poisonous, so don’t be tempted to eat it. Growing mostly on dead wood it can be found in damp forest environments of eastern and southern Australia, extending from Queensland to Tasmania and across to the south-west. Look for it low on tree trunks — the fan or funnel-shaped caps are usually quite distinctive in the daytime once you’re familiar with them. Notice also the branching gills, which extend down the stem. The caps can grow as large as 30cm across. But be aware they only last a few days, so don’t delay going back at night if you want see them at their luminous best. It’s also possible to see the glow by taking a piece into a completely dark room.

The mature caps glow 24 hours a day but you can only see this when there’s no other light. Oh, and don’t expect it to look green like the photos. Our eyes are poor at determining colour in low light situations, so we perceive the glow as white.

Below are a few extra photos showing the variation in form and colour by day. Who would have thought these are all the same species? Scroll down further for some more night shots. Please click the photos to enlarge.

Light and dark forms growing on one tree.

Photographic notes

Most of the night photos on this page are 30 second exposures at 800 ISO and the lens at its widest aperture. As this isn’t very wide on my gear I’ve brightened the images a little and removed some of the graininess in Photoshop but the colour hasn’t been altered.

Reference

Miller, Orson K. Jr. (1994). ‘Observations on the genus Omphalotus in Australia’. Mycologia Helvetica. 6 (2): 91–100.

Further reading

Hunting the Ghost Fungus: glowing mushrooms in Australia’s forests. An interesting short article published recently in the Guardian. Includes animated time-lapse photos showing the change from day to night. I even get a mention!

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Finally, here’s another look at last year’s spectacular display (2016). Click the photo to see more and read about it.