In 1986, when I was working for Agriculture Victoria as a mycologist, I spent a year with my English colleague Dr Brian Sutton, working on a research project to identify new species of plant pathogenic fungi with potential to affect native plants of potential importance in horticulture. We travelled all over Victoria and other states, walking in the bush looking for plants with leaf spots, stem cankers and other disease symptoms.
 
We became, at one stage, very interested in leaf diseases of Banksia species, and got to know the leaf spots on the upper surface of leaves, but also began to see lots of dark fungi growing within the white, tomentose (woolly) undersurface. There were quite a few species of fungi there and all of them were black, so we got into the habit of collecting quite a few leaves with symptoms to look at when we got back to the lab. One leaf of Banksia marginata that we collected in the Brisbane Ranges had a tiny spot on the lower surface, with a tiny black fungus growing out of what looked like a bit of insect damage.
 
We made a microscope slide, put it under the microscope and immediately realised that it was like nothing we had seen before. We knew that we had not a just new species but a new genus. We called it Tryssglobulus aspergilloides (Tryssglobulus from the Greek roots for lovely little ball) and aspergilloides (meaning - looks a bit like Aspergillus). In 1987 we published a paper describing the fungus in the Transactions of the British Mycological Society 88: 41-46. But we never saw the fungus again!

​In the following decades my colleague Pedro Crous in the Netherlands started asking me if I could try to collect more specimens so that he could grow it in culture
and get a DNA sequence to fit the fungus into the family tree of the fungi. And he kept reminding me to keep looking.
 
Thereafter, I could never walk past a plant of Banksia marginata without stopping and looking for Tryssglobulus, but I could never find it. When Pedro’s asking progressed to nagging, I even went collecting in the Brisbane Ranges but still could not find any trace of it. The fungus, having only been collected once, and never seen again despite much searching, was proposed for listing as “Red Listed” in the Fungal Red List as “A very distinctive microfungus, known only from the type locality  in the Brisbane Ranges, Victoria, Australia.”
 
In 2020 I was walking in the Gurdies Nature Reserve with my wife Joy and, of course, looking for B. marginata, turning over lots of leaves without finding anything at first. Eventually I saw a very stunted little plant with brown lesions on the leaf that I recognised as insect damage. Remembering that there was some insect damage associated with the original specimen, I picked several leaves and examined them with my trusty hand lens. On the lower surface amongst the  leaf-miner damage I thought there might have been something growing but it was too small to tell.

I took it home, put it under the microscope and “Eureka!” – it was Tryssglobulus!!
 
At last! I took photos and emailed them to Pedro in the Netherlands. He was ecstatic. I immediately posted specimens to him so he could get it into culture and get a DNA sequence.
 
In the meantime, worried that it might get lost in the mail, I decided to get the fungus into culture myself. I bought some petri dishes, bought some agar from the health food shop and, using our new pressure cooker, sterilised the petri dishes, sterilised the agar in glass bottles and finally poured the melted agar into the petri dishes. I transferred spores of the fungus onto the agar and eventually got it growing, then transferred it to sterilised pieces of banksia leaves and got it producing spores on the leaf pieces. 

In due course Pedro’s team got the sequence and placed it in a phylogram next to its closest relatives. To our disappointment it doesn’t look anything like its relatives! So although we have found it and worked out its place in the fungi, it remains an elusive, enigmatic and beautiful little fungus.

Ultimately the scarcity of Tryssglobulus aspergilloides appears to be due to its cryptic behaviour, hidden, almost invisible amongst the “wool” on the underside of Banksia marginata leaves with damage from a small insect. It is probably not all that scarce, or endangered. Just a very tiny, hard to find, obscure fungus. As for its relationship with insect damage, it seems likely that the damage is caused by the larvae of the Banksia leaf-miner moth Stegommata sulfuratella which burrows into the lower epidermis of the leaf under the cover of the woolly integument. My specimen had a tiny caterpillar crawling around but I failed to get it to pupate and emerge as a moth.  I suspect the fungus gets its nutrition from the frass (insect faeces and particles of leaf) and is more dependent on the moth than the moth is dependent on the fungus. Certainly the fungus is well placed to be picked up and dispersed by the moth as it emerges from its pupa and walks over the little balls covered with spores on the ends of long stalks.
 
Is Tryssglobulus important to the ecosystem of the woodlands?? Probably not. But the Banksia and the moth are clearly important to the fungus. But how can we really know? No-one has or is ever likely to study the complexity of the relationship. It’s just a tiny little obscure fungus that is very unlikely to be important to anyone except me and my colleagues. If nothing else, it’s my favourite fungus of all time and it made me happy!
 
But above all else it is a powerful reminder that the woodlands are full of little things that we don’t yet know about. And some of them will be very important!