Author Archives: Jürgen

Rotters, helpers and roo poo – fungi after fire

Pyronema omphalodes. Photo: David Catcheside.

This winter, Pam and David Catcheside continued their surveys of the fungi on Kangaroo Island after the catastrophic fires of 2019 and 2020. Reports on previous findings were published in these blogs:

After a brief, preliminary survey in April, we considered that July would be optimum for the main survey, which would include Dr Teresa Lebel, Senior Botanist at the State Herbarium of South Australia, Helen Vonow, Curations Manager, and Julia Haska, an Herbarium Research Associate. However, a COVID lockdown aborted that trip: Julia was already on the island, but just as Teresa and Helen arrived at Cape Jervis, well ahead of time for the noon ferry, they learned a lockdown would start at 6pm. Pam and David were en route at Lucky Bay so as a small compensation we all met up at Deep Creek Conservation Park to look at fungi there, before heading home in time for the curfew. The variety and abundance of fungi at Deep Creek made it even more galling that we were not able to explore the fungal offerings of Kangaroo Island, though we did make some interesting collections.

Although Teresa, Helen and Julia were unable to join us, we were able to schedule a week-long KI trip in late August. However, as the fungal fruiting season in South Australia is usually from June to early August, we knew we had missed the optimum time. An additional constraint was that some sites we usually survey were off limits due to feral pig control operations.

We recorded 35 species of fungi, making collections of 27 of these. One third (10 species) were fire-associated, pyrophilous species and included disc, stonemaker, as well as wood-rotting fungi.

Disc fungi

Disc fungi are amongst the early colonisers, forming mats over the soil surface, helping to bind soil particles and reduce erosion. We found a few patches of the orange Pyronema omphalodes (above) and scattered groups of Pulvinula, whose bright orange discs with their paler, smooth and hairless undersides stand out against the burnt soil.

Pam never trusts the outward appearance of the majority of disc fungi, recognising that the microscopic characters of ascospore size and number, ascus size and shape and features of other cell structures are necessary to determine species. Indeed, each of the four collections of Pulvinula that were made differed in some of these characters, suggesting they belong to different species, two of them possibly undescribed. Planned molecular work will clarify this.

Pulvinula tetraspora (left) and its 4-spored asci (right). Photos: David & Pam Catcheside.

Other pyrophilous disc fungi such as species of orange Anthracobia and black-brown Plicaria and Peziza, found after the 2007 fires and in 2021, were absent. It is possible that these had fruited early this year in June or July but it appears probable there is a lower abundance and fewer species of pyrophilous discs than after the 2007 fires.

Pulvinula sp. (left) with 8-spored asci (right). Photo: David & Pam Catcheside

Mycorrhizal fungi

Scleroderma albidum, an earthball. Photo: David Catcheside.

Mycorrhizal fungi are essential in all forest ecosystems, providing minerals and water to their partner tree. Laccaria species, common colonisers of land cleared by fire or other disturbance, were present, but few other mycorrhizal fungi were found — just a few specimens of Amanita and Cortinarius and an earthball, Scleroderma albidum (right).

Mycorrhizal fungi are expected to be affected when their symbiotic plant partners are killed by fire (Dove & Hart 2017) so it is not surprising that they will be depleted following fire. Again, it is possible that they fruited earlier but it is of concern that we found so few of these important fungi.

Wood-rotting fungi

Fungi are responsible for much of the breakdown and recycling of organic matter, releasing nutrients and making them available for new plant growth (Ingold & Hudson 1993; Crowther et al. 2012). After the summer fires of 2019-2020 there was plentiful substrate:  large quantities of fallen bark, dead branches, logs and trunks were at all sites. Rainfall on Kangaroo Island in 2021 had been high and we had expected to find fluffy mycelium and patches of flat ‘paint’ fungi on some of the wood. However, in spite of our careful examination, even the lowest and dampest layers of the piles of fallen bark showed little evidence of the usual ‘rotters’. We surmised that the fungal inoculum was insufficient to start breakdown of the bark.

]We did find a few wood-rotting bracket fungi. One of the most common was Porodisculus pendulus, which grew in extensive swarms up the burnt trunks of eucalypts. This is a small hoof-shaped pored bracket and the specimens were much tinier, less than half the size, than those we had found after the 2007 fires. We also noted the lilac bracket, Rhodofomitopsis lilacinogilvaand shelf fungus, Stereum hirsutum, but these are not considered to be obligate fire-associated wood rotters.

Wood rotting fungi: Porodisculus pendulus on burnt eucalypt trunks (top), Rhodofomitopsis lilacinogilva (middle), and Stereum hirsutum (bottom). Photos: David Catcheside.

Dung fungi

On a brighter note! One little fungus that was in abundance was Poronia erici. It was growing mostly on kangaroo dung but it also grows on the dung of other marsupials. It forms hard white button-like discs punctuated with tiny black pores which communicate with minute ascus-containing flasks embedded in the disc. Spores are released through the narrow necks of these flasks. The presence of this fungus is a positive sign that marsupials are returning to the burnt sites on Kangaroo Island and possibly reintroducing fungi lost to the fire.

Poronia erici. Photo: David Catcheside.

Monitoring of fungal succession after fire and re-establishment of pre-fire fungal assemblages may inform better management of the environment after fire. It was unfortunate that COVID-19 prevented us from a proper assessment this year.

Further reading

  1. Atlas of Living Australia. Pulvinula Boud.
  2. Catcheside, P. (2009). Phoenicoid discomycetes in Kangaroo Island. Fungimap Newsletter 38: 5-8.
  3. Crowther, T., Boddy, L. & Hefin Jones, T. (2012). Functional and ecological consequences of saprotrophic fungus–grazer interactions. ISME Journal 6: 1992–2001.
  4. Dove, N.C. & Hart, S.C. (2017). Fire reduces fungal species richness and in situ mycorrhizal colonization: a metaanalysis. Fire Ecology 13(2):37–65.
  5. George, P. (2008). Fungimap survey on Kangaroo Island. Fungimap Newsletter 36: 13-15.
  6. Grgurinovic, C.A. (1997). Larger Fungi of South Australia. (The Botanic Gardens of Adelaide and State Herbarium and The Flora and Fauna of South Australia Handbooks Committee: Adelaide).
  7. Ingold, C.T. & Hudson, H.J. (1993). Ecology of saprotrophic fungi. In: The Biology of Fungi, pp. 145-157. (Springer: Dordrecht).
  8. McMullan-Fisher, S.J.M., May, T., Robinson, R., Bell, T., Lebel, T., Catcheside, P. & York, A. (2011). Fungi and fire in Australian ecosystems: a review of current knowledge, management implications and future directions. Australian Journal of Botany 59: 70-90.

Contributed by Pam Catcheside (State Herbarium Hon. Associate)
David Catcheside (Flinders University).

Spring is here!

Pond in Rymill Park. Photo: B. Baldock.

Lengthening days, bursts of warmer weather – it must be spring. And with it, flower buds of terrestrial plants that have been surreptitiously developing over winter may suddenly burst into a great show of reproductive activity. But also, perhaps not as obvious, and often poorly appreciated, is the frantic activity in freshwater creeks, ponds and water storages in preparation for the drought of coming summer.

We are fortunate in the State Herbarium of South Australia that we have enthusiastic volunteers who not only help greatly in the day-to-day activities of the herbarium, but keep an eye on changing natural events and bring in plants that appear unusual or noteworthy. Recently one of our volunteers brought a sample of green “slime” for us to investigate. It was wrapped around the minute roots of some floating duckweed blown to the edge of a nearby city park pond.

Under the microscope a whole ecosystem of plants and animals was revealed – something more remarkable than the term “slime” implies. The basis of this ecosystem was a striking green alga – Oedogonium. This had strange swellings, some green, some reddish, along the lines of green cells that make up the unbranched threads or filaments of its plant body or thallus.

Oedogonium algae filaments with pine pollen (top image). Photos: B. Baldock.

Interspersed among the filaments were pine pollen grains that had dropped into the pond. These looked like Mickey Mouse hats, hence they were easily identifiable. There were also many colourless, single-celled animals going about their business, mainly filtering out single-celled algae or other animals smaller than themselves.

The filaments also acted as the base for minute threads of innocuous, colourless sulfur-bacteria less than 1 millionth of a metre (1 μm) in diameter. These could be identified, because they contained minute droplets of sulfur that caught the light brilliantly under the highest magnification of our microscopes.

Excitingly, the Oedogonium was reproducing. Swollen cells were acting as eggs (oogonia), and some had tiny attachments – dwarf “males” (or antheridia) – that were fertilizing the oogonia (males can be produced by neighbouring filaments or the same filament). Following fertilisation, red-brown, tough-walled zygotes had formed, ready to germinate into a new filament if conditions were right, or to sit dormant in the dried mud of waterways until the coming rains next season.

Oedogonium algae filaments with sulfur bacteria, oogonium (egg) and antheridium (male). Photos: B. Baldock.

It’s a pity that algal growth in our waterways such as that described above is denigrated. We are conditioned into thinking water bodies should be clear and blue, a state generally signalling they are sterile and lack vibrant, living ecosystems.

And, we rightly fear the appearance of the grey-green scum of toxic, blue-green “algae” that may form in waterways towards the end of summer. But, to be correct, “blue-greens” are bacteria, not true algae. This bacterium blooms at the boundary between an upper, warm, brightly lit layer and a nutrient-rich, cooler bottom layer that forms in still, non-flowing bodies of water. In cities, the nutrients generally come from wastewater run-off, including garden fertilizer and domestic pet excrement.

As a response to blooms of organisms in freshwater we seasonally often add our own toxins such as copper salts and hydrogen peroxide to kill them, wrecking benign living aquatic communities that may have helped in past times to obviate the threat of these blue-greens, by denying them excessive nutrients and establishing broader and more stable food-pyramids.

I hope you agree with me that green ”slime” can be more interesting than its name suggests. And perhaps you might appreciate it, understand its complexities and learn to live with it rather than try to obliterate it.

Further information

  • Entwisle, T.J., Sonneman, J.A. & Lewis, S.L. (1997). Freshwater algae in Australia. (Sydney : Sainty & Associates). – The book is being converted to a website, part of which is already available online.
  • CSIRO (2021). What are blue-green algae. [accessed: September 6, 2021].

Written by Hon. Research Associate Bob Baldock.

Research news: Ptilotus in arid Australia

A new paper on the evolution of the genus Ptilotus in arid Australia was published by Tim Hammer, who is currently working as a post-doc at the State Herbarium of South Australia and The University of Adelaide with Chief Botanist, Prof. Michelle Waycott.

T.A. Hammer, M.Renton, L. Mucina & K.R. Thiele. Arid Australia as a source of plant diversity: the origin and climatic evolution of Ptilotus (Amaranthaceae). Australian Systematic Botany 34: 570-586.

Ptilotus rotundifolius, Murchison region, WA. Photo: T.A. Hammer.

The authors tested the chronological and geographic origins of the mostly arid Australian genus Ptilotus (Amaranthaceae) and its close relatives (i.e. the ‘aervoids’) by reconstructing a dated phylogeny with near comprehensive sampling for Ptilotus and estimating ancestral geographic ranges. Their analyses support the hypothesis that a pre-adaptation to aridity and early arrival in an aridifying Australia were integral to the success of Ptilotus, and that the Eremaean zone has been a source of biodiversity in the genus and for independent radiations into neighbouring climatic zones.

Tim now works on Hibbertia (Dilleniaceae), one of the most species-rich genera in Australia, in collaboration with State Herbarium Honorary Research Associate Hellmut Toelken and colleagues from South Australia and interstate.

Research news: fungi papers published

During the last week, two papers were published by State Herbarium of South Australia‘s mycologist, Dr Teresa Lebel, and co-authors in the online version of the journal Mycologia:

Agaricus xanthodermus, p = pileus; s = stipe; a = annulus. Photo: A.-G. Boxshall.

(1) A.-G. Boxshall, J.L. Birch, T. Lebel, M.R.E. Symonds & D.L. Callahan (2021). A field-based investigation of simple phenol variation in Australian Agaricus xanthodermus. Mycologia (Publisher’s website).

Agaricus xanthodermus (yellow stainer) and other species of the yellow-staining Agaricus sect. Xanthodermatei are responsible for mushroom-related poisoning cases that require treatment. However, longstanding anecdotal evidence indicates that this species appears to exhibit considerable variation in toxicity, resulting in gastrointestinal irritation of varying severity in most cases. During her MSc research, the first author quantified the amount of phenol, hydroquinone and catechol in mushrooms and investigated their levels in different fungal structures, different developmental stages and on different nutritional substrates.

(2) J.I. de la Fuente, J.P. Pinzón, L. Guzmán-Dávalos, M.O. Uitzil-Colli, D. Gohar, T. Lebel, M. Bahram & J. García-Jiménez (2021). Revision of the genus Restingomyces, including two new species from Mexico. Mycologia (Publisher’s website).

The paper is the result of a long-standing collaboration to document the truffle diversity in American tropical regions. After a series of field surveys in southeastern Mexico, two new species in the phalloid genus Restingomyces (Trappeaceae, Phallales) were discovered. The authors describe them based on morphology and phylogenetic analyses of molecular data. Restingomyces guzmanianus and R. yaaxtax occur in medium-statured tropical dry forests. The original diagnosis of the genus Restingomyces is emended to include these novel species.

The new South American truffle Restingomyces guzmanianus, A = truffle cut in half, B = outside. Photo: J.I. de la Fuente et al.