Mystification

While walking the Highbury Fling track (18 November) Margaret Crimp and Anne Conwell came across this strange object growing on a fallen pine tree (Pinus radiata). They said it was about 6 cm across with a membranous cover which had split open.

“We were mystified – wondered if it might be fungal. Have you any idea what it might be?”

My first reaction was it didn’t ‘look right’ for a fungus. It seemed too big and the membrane was too papery when compared to how wet the inside of it looked through the cracks. I was thinking slime mould but I hadn’t seen anything like it before.

Slime mould?

I did a quick trawl of the internet and found this picture by Tony Wills of a similar thing again on pine and in Wellington. Tony’s caption of the photo said:

“Apparently some form of slime mold in the form of a white/cream lump ‘growing’ at the base of a Pinus radiata tree stump. Perhaps related to Fuligo septica, but always found in this domed form. 3 to 4cm diameter. Wellington, New Zealand.”

So searching the internet again came up with another slime mould Enteridium lycoperdon (Reticularia lycoperdon). Margaret and Anne’s slime mould is likely to be an immature fruit body of this species.

Living soup

Slime mould live as a plasmodium – like a living soup flowing through the soil eating bacteria, spores, and other organic material.

When the plasmodium is big enough and weather conditions suitable it ‘climbs’ to a high place where it coalesces into a solid, spherical body and begins to turn itself into a fruit body. This involves the out part forming a protective membrane. Meanwhile, the inner tissue begins to form into spores. Eventually, the inner tissue becomes a solid mass of dry powdery spore, the outer membrane ruptures and the spore blow away in the wind to start the cycle again.

The plasmodium photo is by Sarah Lloyd, an Australian with a passion for slime moulds.