Asterostroma (Asterostroma spp.)

Asterostroma is a genus of fungi to which over 20 different species belong, two of which are known wood destroyers in buildings. This is the asterostroma cervicolor and the asterostroma laxum. They are among the more infrequently found fungi in buildings, but are capable of doing extensive damage. As they prefer moist locations, they usually occur in damp roof structures or on timbers in damp cellars. They form strands which enable them to grow on wood and masonry. The fruiting bodies are also found on mineral walls.

Asterostroma cause white rot and are particularly interesting because of their striking microscopic characteristics. In the fruit body and the mycelium, these fungi form star-shaped structures – the so-called asterosetae - and it is still not known what function these structures perform.

What do Asterostroma look like?

The colours of the fruiting bodies of the asterostroma cervicolor range from yellowish to light brown and have a felt-like texture. They lie flat on the substrate and are about 1mm thick. On the margins, their colouring is lighter.
The asterostroma laxum’s fruit body is an apricot to orange colour and, in contrast to the fruiting body of the asterostroma cervicolor, they spread in strands.
Under the microscope, these fungi are easy to identify due to their star-shaped asterosetae.