I found a strange substance growing between a pile of plastic sacks containing bark mulch and a wall in my garden (see photo, top left). It was July and the sacks had been piled against the wall for some weeks. At first I thought it was a piece of foam plastic, but when I touched it the stuff had the consistency of mousse. You can see the reddish mark where I prodded it. The second photo is a close-up of one of the holes and the surrounding fibrous structure. The patch was about 17 centimetres long and during the course of the day it dried, went crumbly and turned more pink. Does anyone know what it is?
Alistair Scott, Gland, Switzerland