Postia

This was growing on a the underside of a piece of processed wood that had been lying on the ground in a suburban garden for many years. Hence, the pores were facing down. There are a number of polypore genera in which the fruit bodies are essentially flat against the underside of dead wood, as appears to be the case in Photo 1, and sometimes the edges may be loose and turned out from the wood. In Photo 2 the white scale bar represents one centimetre. In Photo 3 I show a closer view of the pore surface and you can see that the pores are angular and sometimes a little elongated. What you see in Photo 1 is not just a simple fruit body flat against the wood. In Photo 4 I show the fungus in its natural orientation and, at first glance, it appears that there is a fruit body that hangs down from the wood via a number of supports. However, what you see in Photo 1 is not one fruit body, but a number of separate fruit bodies that have merged. Each fruit body is small and pendant, which starts as a downward growing stem and broadens to produce the pored layer. The pored layers of neighbouring fruit bodies have merged. The distance from the wood to the pored surface is about 5 millimetres. The fruit bodies are soft when fresh and of a somewhat chalky consistency when dry. Identification to genus needed a look at the microscopic features and I have kept this specimen for lodgement at the Australian National Herbarium as collection HL6142 . It was easy to cut off a thick slice of wood with the mass of fruit bodies left intact. In Photo 5 I show the reverse side of that slice and you see that within the wood the fungus had caused a brown rot. Very few polypore species produce pendant fruit bodies and there are at least two species of Postia that do so .