lilac. There is a relatively thick layer of gelatinous flesh. Apart from a brown layer close to the wood, the flesh is hyaline. The species has no distinctive odour or taste, and is inedible. Microscopic features Peniophora quercina produces spores that take the shape of a curved cylinder (sausage shaped), and have been variously reported as light red, pink and white. They measure from 8 to 12 by 3 to 4 micrometres (μm). The spores are borne on basidia, with four spores per basidium, which measure 50 to 70 by 5 to 12 μm. The species has hyaline cystidia with thick cell walls, which are "heavily encrusted with crystalline material". The cystidia are often buried within the fruit body as it grows, but can be found in large numbers. They have been variously described as spindle-shaped or conical, and measure 25 to 35 by 10 to 15 μm. The hyphae have clamp connections, and the base of the fruit body is made up of brown hyphae with moderately thick cell walls, measuring 3 to 4 μm in width. Similar species Peniophora limulata is similar in appearance to P. quercina. However, the edges of the fruit body are highlighted in a dark black, and the species favours ash, as opposed to oak. Ecology and distribution Peniophora quercina typically grows upon dead wood, which can be attached to the tree or fallen, where it causes white rot. It favours oak, but can also be found on other deciduous trees, such as beech. P. quercina is known to be a pioneer species on dead wood, which means it can be the first species to grow. It is found in Europe, where it is very common. Though it can be encountered all year, it produces spores in late summer and autumn. It has also been recorded in Amur, in eastern Asia. The species has also been identified in living sapwood, though it is latent at this time, and it is probable that it waits until the wood begins to die (when it is drier, but contains more oxygen) before the mycelia begin to grow. When the species was inoculated into living wood, it did grow, but only around the inoculation wound; the species did not spread as it would have done on dead wood. Another study found that the species actively colonised partially living branches, causing white rot. However, the species had little effect