Slime mould log

by Sarah Lloyd

October 2015

A Fallen stringybark

fallen stringybark
fallen stringybark

In early April 2014 I heard the loud crash of a falling tree from down the hill. The origin of such sounds is difficult to pinpoint but a week or so later when visiting Thismia Gully I discovered its source. A massive stringybark (Eucalyptus obliqua) about 30 metres tall, had fallen across the gully. The root end of the tree, which had been dead for some time, is close to the bed of an ephemeral creek and had no living roots to hold it in place in the waterlogged soil.

Fortunately, access to three sections of the trunk is possible without having to do too much clambering over the numerous dogwood (Pomaderris apetala) and musk (Olearia argophylla) that the tree had brought down with it.

While still standing, the stag (upper branch) of the tree had emerged from above the canopy of blackwood (Acacia melanoxylon) and had lost most of its bark. In places it was soft and spongy and covered in a white, toothed resupinate fungus. Fortunately, its spongy nature and convenient height makes collection and observation easy.

A large lower branch about mid way along the trunk is reasonably easy to access except for some small upper branches of dead dogwood and musk. (The main trunk is beyond reach at this point which can be frustrating if any of the larger myxos - e.g. Stemonitis - are visible.)

Inspecting the lower end of the trunk doesn’t require much clambering and I have been checking it regularly since the tree fell.

Physarum virescens
Physarum virescens

My first collection from the stag end is dated April 8 2014 and was eventually identified as Physarum virescens. The fruiting bodies are clustered, greenish-yellow stalked and sessile (stalkless) sporangia in good condition, i.e. the peridium is mostly intact. This is the first record for Australia according to the Atlas of Living Australia (ALA) which also records only two collections from Zealand. The same species appeared again at the same place on January 21st 2015 but has not appeared since.

Paradiacheopsis rigida
Paradiacheopsis rigida

Alongside the P. virescens was Paradiacheopsis rigida, a tiny 1–1.5 mm high fruit body that appeared in extensive colonies after each bout of rain between April and June 6th, the date of the last collection. I have tried to collect equally tiny species from newly fallen trees many times, but the substrate is extremely hard so collecting them undamaged is almost impossible. The spongy substrate on the stringybark made this relatively easy. Intermingled with the P. rigida was the maypole-like Enerthenema papillatum, which also reappeared after rain. This species was common in 2014 and collected from numerous substrates in different locations. Before 2014 I had only collected it once and I have not seen it since - such is the unpredictable nature of slime moulds.

Physarum viride
Physarum viride

Physarum viride was also common on the stag in 2014. This was a common species when I started collecting but it has only appeared twice so far in 2015 and was the only myxo I collected from the stag in 2015.

Arcyria globosa
Arcyria globosa

Also collected at various sites along the trunk in 2014 were Arcyria riparia, A. globosa, Physarum album, Comatricha alta, Trichia botrytis, Cribraria sp. Stemonitis sp. and Lycogala epidendrum.

September - October 2015

Clastoderma debaryanum
C. debaryanum

In September/October 2015 the stag end, being off the ground, was dry and unproductive. The root end, which is also off the ground but in a shaded location above the ephemeral waterway, had extensive colonies of numerous different species. As the tree had been dead before it fell, there could be considerable decay within the log, something that is difficult to determine because it is still hidden by the covering of stringy bark, much of which stays sodden after rain. It was covered in numerous slime moulds of various species at various stages of maturity - Metatrichia floriformis, Trichia affinus, Trichia decipiens, Diderma sp., Comatricha sp, Ceratiomyxa fruticulosa, Clastoderma debaryanum and the beautifully iridescent Elaeomyxa cerifera.

In my experience the variety of different species on a newly fallen tree is not unusual. I have checked several such sites since starting my research. They seem to remain productive for about a year after they fall. The fallen stringybark is particularly rich possibly because of the large size of the trunk.

Enerthenema papillatum
Enerthenema papillatum
Elaeomyxa cerifera
Elaeomyxa cerifera
Cribraria stellifera
Cribraria stellifera
Diderma species
Diderma sp.
Ceratiomyxa and metatrichia.JPG
Ceratiomyxa & Metatrichia
Paradiacheopsis rigida
Paradiacheopsis rigida

log 1 | log 2 | log 3 | log 4 | log 5 | log 6 | log 7 | log 8 | log 9

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