It was shocking pink lipstick in the 1960s. Now shocking pink fungus is appearing on our trees!
Illiosporiopsis christiansenii is a bright pink fungus which grows on various lichens that are common in nitrogen-enriched places. Although Whiteknights is not close to any major pollution sources, the lichen habitats on our trees (and on other surfaces) receive extra nitrogen from car exhausts within the town. This means that nitrogen-loving lichens are common throughout the campus.
I. christiansenii grows on a variety of host lichens but can be found most commonly on the grey Physcia tenella and the closely related Physcia adscendens. The fungus forms pink lumps and bumps composed, almost entirely, of spiral-shaped spores. These masses disintegrate rapidly in water and are probably spread by rain splash.
Tom Preece, writing in the British Lichen Society Bulletin in 2011, pointed out that the fungus had been recorded almost exclusively between August and March in Britain so may be seasonal in its occurrence.
Preece, T. (2011) Another lichenicolous fungus you can look out for. British Lichen Society Bulletin 109