Pleurotus citrinopileatus

August 16, 2021

Good morning friends,

Mushroom Monday has gone mobile. I’m sitting at a cafe in Denver after wrapping up a weekend at the North American Mycological Association’s annual foray in Granby, CO. A powerful and inspiring weekend.

This week’s mushroom is Pleurotus citrinopileatus, commonly known as the golden oyster mushroom. We’ve looked at Pleurotus ostreatus before, which is commonly seen throughout the park, but this was the first time I encountered P. citrinopileatus which is significant for a variety of reasons. This mushroom was found on 7/19/2021 on a cherry tree (Prunus) in the middle of the boathouse lawn.

P. citrinopileatus is native to Asia, specifically eastern Russia, China, and Japan. Like all Pleurotus species it is saprobic and can obtain nutrients from a variety of dead organic material – in this instance wood. If you noticed, P. citrinopileatus is not native to North America and is one of the first recognized “invasive” mushrooms. It’s commonly cultivated for culinary purposes, but it has escaped cultivation and as of 2012 it is now found growing wildly throughout the eastern part of the continent. The consequences of this introduction are unknown, and have yet to be studied (aside from one master’s thesis – see Reference 3), but we should at least be cognizant of its presence and expanding range.

The idea of invasive species can be a controversial one in ecology. In the natural areas, we plant native plants and remove invasive, or non-native, plants to help increase biodiversity (the diversity across all kingdoms of life in an ecosystem). However, the fact that the earth is so interconnected, and humans ourselves aren’t necessarily “native”, makes some dismiss the idea of strictly planting native plant species. I’m of the belief that we want a wide array of flora, fauna, and funga because this diversity of life creates an overall more resilient and healthy ecosystem. Left to it’s own devices, japanese knotweed (Reynoutria japonica) would create a monoculture in our natural areas – as it has in many disturbed landscapes throughout the country – which severely limits the diversity & quantity of life both above and below ground.

The question many are pondering today is whether the introduction of P. citrinopileatus will have a similar effect on fungal diversity as noxious invasive plants have had on plant diversity. Unlike plants and animals, fungi are filamentous strands unseen in the soil so measuring fungal diversity isn’t as easy as just using your eyes. At the minimum we can say that P. citrinopileatus is occupying and competing for the same resources as native Pleurotus species. It should be noted that P. citrinopileatus is a choice edible containing several different minerals, amino acids, and carotenoids. It was also shown to slow the growth of human leukemia cells along with possessing a variety of other mildly substantiated medicinal claims (Reference 2). At the very least this introduced species is nutritious for insects, animals, and humans. All we can do for now is monitor the spread of the species – and consume it – while hopefully more research is conducted on the implications of its introduction.

Enjoy these dog days of summer,