May Workshop: the diversity & ecology of fungi

10th May, 2019


Amid an impressive evening thunderstorm, a large group of interested naturalists gathered to hear about our local fungi from Teresa – an amateur mycologist with 25 years experience of investigating fungi and slime moulds in our region. Many of the beautiful images on show during her presentation were the work of Teresa and partner John. We thank them both for sharing these with us.

There was also a treasure trove of the real thing on hand for investigation …

Some of the mushrooms and other fungi brought along to the Workshop

Some of the mushrooms and other fungi brought along to the Workshop

As a follow-up, I’ve examined two of these in detail:

Horse dung fungus (Pisolithus marmoratus)

A couple of people brought in these bizarre, round fungi. Their real beauty (or interest, anyway) is only revealed when the fungal heads are cut in half. They can grow in clumps, and be quite large. Draught horse-sized! The largest we had in the collection was 9cm diameter, heavy and quite hard.

Andrew and others commented that these fungi are commonly seen growing at the edge of roads. They can even break through the tarmac as they push up from below! This raised the question: “Is there a particular association between Pisolithus and bitumen?”

After doing a bit of checking, I don’t believe so. It has been noted, however, that they tend to grow in disturbed, well-drained, sandy soils (ref). The road edge rather fits the bill!

Pisolithus marmoratus does form mycorrhizal associations with trees from the Myrtaceae family, and it doesn’t live long without its host (ref).

The spores in Pisolithus are formed within pea-shaped compartments, quite unlike the ‘free spore’ arrangements of most puff balls. The most mature spores are towards the top of the fungus, and when it splits, these are released first. The others follow, progressively. It is these packets of maturing spores that give the cut fungus its interesting colours and pattern.

The colour, size and surface structure of spores are often useful features for distinguishing between otherwise similar species. In this case, it wasn’t necessary … but we imaged them anyway, just for fun.

Paul took these shots by dropping some spores from one of the open-topped, mature fungi onto a glass slide, adding a drop of water, and then using a high magnification microscope with attached camera.

Fungal spores tend to be rather small, but at nearly 1/100mm, these ones are on the larger side. They were greenish-brown when viewed as a spore print (i.e. without the microscope).

Purple puffball (Calvatia lilacina tbc)

This large, purple puff ball was brought in by Norm. It was 11cm in diameter, very light, and with a dry papery case that had clearly burst open. When squeezed, it felt rather like a soft sponge.

And it was a fungus I’d never seen before! However it was familiar to Jackie as it occasionally appears on their Brogo property, growing near a dam.

Another, larger member of this same genus is quite well-known in Europe. C. gigantea is, well, gigantic. It is eaten when young, but quite poisonous once the spores mature (Wikipedia ref). Not worth the risk, I think. Anyway, as C. gigantea is reportedly mycorrhizal, our local Calvatia species is likely to be also. Teresa may have more information, and if so I’ll pass it on.

Again Paul took some shots of the spores. Not for any real reason, but just because I asked nicely.

The spores are purple (no surprise), and consistent in size and shape to those reported elsewhere for this species (ref).

A few fungal facts

Teresa’s talk touched on a wide range of concepts, and so I thought I’d pick up on just a few.

1: Shape is not a reliable clue to relatedness

For convenience, fungi are often grouped based on their overall structure (i.e. morphogroups). Gilled Mushrooms, boletes, stalked puffballs, corals, etc. But just because two fungi have a similar shaped fruiting body, does not mean that they’re closely related.

Equally, two close relatives can indeed look very different. Similar shapes have evolved multiple times in the evolution of fungi.

Evolutionary relationships between some familiar fungi

2: Many young fungi have wrappings … ‘veils’

Partial veils
It is particularly common for mushrooms to keep their delicate gills covered until they have grown up and away from the substrate. These are usually called ‘partial veils’, as they cover only part of the fruiting body. And they are a handy feature to help distinguish between species. Take note of the veil texture and, when it has torn away, look for any remnant fragments on the rim of the cap and/or on the stem (‘stipe’). Some mushrooms retain a very obvious ring of partial veil surrounding the stem, and this is referred to as an annulus. Just terms, but useful ones if you’re using a field guide for identification.

The partial veil in this young Cortinarius cap is just beginning to tear away. Confusingly, the particular web-like partial veil in this genus is referred to as a ‘cortina’. It’s a partial veil, all the same.

Universal veils

The fruiting bodies of some fungi are initially completed wrapped in a covering, from ‘head to foot’. This is called a ‘universal veil’. Again, the remnants of this veil can provide important characters for species identification. In particular, look for: bits of extra material stuck to the cap; and a cup of tissue surrounding the base of the stipe. This basal cup is referred to as a volva. Again, a bit of handy jargon if you are using a fungi field guide for identification.

I found this common little mushroom today - Amanita xanthocephala. The cap and stipe both clearly show remnants of a universal veil.

3: Truffle has a different meaning for mycologists

Talk to a chef or fine food connoisseur, and they will have a very clear idea of what a truffle is. They will be referring to just a handful of fungal species, mostly from a single genus, Tuber (Wikipedia ref.).

But in mycology circles, ‘truffle’ or ‘truffle-like’ usually refers to any fungus in which the fruiting body remains underground and doesn’t actively disperse its spores (ref).

The development of a ‘truffle’ lifestyle has occurred many times in fungal evolution. As Teresa highlighted, there are even Cortinarius species that produce truffles. In a dry climate, keeping your spore-producing structures protected seems a good idea. It must be, as so very many species do it! Heino Lepp’s detailed discussion is worth a read if you want to learn more about Australian truffles.

Collembolans love fungi

Everyone - or nearly everyone - loves a mushroom. But collembolans seem to love them more than most. Take a close look between the gills of the next agaric you see, and you’re likely to spot small animals scurrying about.

Also called ‘Springtails’, collembolans are closely related to insects (ref). They have six legs. And they are typically tiny, just a few mm in length. So slipping between the gills of an agaric is no problem at all.

These tiny animals are virtually ubiquitous, but they need high humidity. Turn over a rotting log, or dig up a patch of moist soil, and you will almost certainly uncover collembolans.

There are estimated to be around 2000 species in Australia. Some feed on detritus, some are predators of even tinier animals, and many feast on fungi. They help organic matter recycling, and also aid in dispersal of a whole range of microbes.

The typical density of collembolans in Australian leaf litter and soil is 2000 - 30,000 per square metre!

Springtails leap to avoid danger. A large, fork-like structure beneath the body is under tension and, when released, catapults the animal, sometimes 30cm or more! A long way if you’re only 2mm long.

Of course, mushrooms also play host to a range of true insects. The larvae of flies are often among the early invaders, while young thrips (Order: Thysanoptera) are also a common sight. Paul found several colourful thrips among the gills of the same mushroom cap. A miniature zoo.

Here is a short video of one of these thrips searching for spores.

The morning after the night before

Flashes of lightning and crashes of thunder accompanied the Workshop, and many of us drove through heavy rain on the way home. So perhaps I shouldn’t be surprised by the treats that awaited me when I took a short stroll in our local forest this morning.

A small handful of the fungi collected from among the leaf litter of the forest floor on Saturday morning, 11th May

A small handful of the fungi collected from among the leaf litter of the forest floor on Saturday morning, 11th May

A glorious splash of colour, including some glistening jellies.

Plus a real bonus: a type of fungus we’ve never seen here before. A stalked puffball! Calostoma sp., I believe.

I’m not sure which part is the most intriguing. The structured opening at the top, or the incredible latticework of the stalk.

Atlas Naturalists: a fresh look coming soon!

The Workshop concluded with a round-table discussion of how we might refine and improve Atlas Naturalists. The suggestions and feedback we received were extremely constructive and helpful. Paul and I will use this to reshape the program for the rest of 2019. More information coming soon!

A few fungi resources

The Australian National Botanic Gardens website has an extensive and very helpful section on fungi. Their structure, their identification, and their importance ecologically. Prepared by Heino Lepp.

FungiMap. Teresa referred to FungiMap. Their website includes a wealth of information, and is an excellent first-stop in learning more about Australian fungi. The sections on photography and recording, for the purposes of ID, are particularly helpful.

Books: Again, Teresa showed a list of useful books and field guides. They are listed on the FungiMap ‘Shop’ web page. Some are likely to be available in libraries. Also note that we have several of these in our home library, and we bring them along to each Atlas Nats Workshop.

I prepared this summary using images taken here, today, by Paul and me. Any errors in details or identification are mine alone … although I hope they are few, and minor.
Kerri-Lee Harris, 11th May, 2019.

Kerri-Lee Harris