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.

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

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 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

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.

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.