May Salt Spring Fungus of the Month: Pleurotus Ostreatus

May's fungus of the month is the Pleurotus Ostreatus group, a handful of species in the Pleurotus genus that can be difficult to tell apart without a microscope. These oyster mushrooms can be found around the Rock on dead and nearly-dead trees in April and May, like this one growing on the south end:

Observation by leafygreeny

The Carboniferous Period began about 360 million years ago and lasted about 60 million years. During this period, plants evolved the ability to make lignin, a hard biological polymer. The plants used lignin to strengthen their cell walls, resulting in sturdy plant tissue: wood.

Nothing alive then could eat or even damage the wood. Forests covered the earth. When a tree died and fell over, it just lay on the ground unrotting and invincible. Water and dirt piled up on the hard fallen trunks, and eventually the weight of the ground above them compressed the trees into coal. "Carboniferous" means "I carry coal". Nothing could destroy the lignin, only squash it into rock-like coal with the polymers intact.

Until the oyster mushrooms and their friends evolved, that is. They're "white rot" fungi - fungi that can create enzymes that digest lignin. They're the reason no new coal can be created - wood doesn't lie unchanging on the ground for thousands of years any more. Before a handful of years have passed, white rot fungi take apart the lignin structure inside wood return the nutrients to the soil.

Here is a scientific article dating the evolution of species of fungi with lignin-digesting enzymes to the end of the Coal-Carrying era.

There are many kinds of white rot fungi, but Pleurotus species are particularly good at taking apart difficult long chain molecules with enzymes. The mycologist Paul Stamets has experimented with using oyster mushrooms to break down diesel in bus yards and petroleum in oceanic oil spills.

Observation by caladri

They're also quite tasty cooked, with a slippery and slightly rubbery texture. They're traditionally used as a vegetarian replacement for shellfish, leading to the common name "oyster mushroom."

On the Rock, oyster mushrooms can be bought at Thrifty Foods, but they don't sell very quickly and tend to set for a while in the store and get dried out and sad.If you want to cook them in some way that doesn't work with half-dried mushrooms, there are often venders selling them at the Saturday Market in Centennial park.

Posted on June 8, 2019 04:23 AM by corvi corvi

Comments

No comments yet.

Add a Comment

Sign In or Sign Up to add comments