Wednesday, May 8, 2019

Hemlock "Reishi", Ganoderma tsugae, Varnish Shelf Mushroom--Eat it young!

Fully grown Ganoderma tsugae on hemlock trees

Some warmer weather is finally signalling the Ganoderma tsugae to fruit. We find them on eastern hemlock trees (Tsuga canadensis), dead or nearly dead trunks. Our eastern hemlocks are under a lot of pressure from several sources that are killing them in large numbers: from the woolly hemlock adelgid--an invasive insect; to various fungal blights and infections--tip blight, twig blight, needle rusts. The amount of dead hemlock trees is steadily increasing, creating more substrate for the "hemlock reishi", or "varnish shelf" fungus.

Fresh fruiting body, soft and tender at this stage

Ganoderma tsugae is a white rot or butt rot of the heartwood for the hemlock tree. It can act like a parasite on live trees and a saprobe on dead hemlock wood. The fruiting body is a firm polypore that shelves out horizontally from the substrate, sometimes in large colonies. The top of the fruiting body comes in a range of colors that changes as it ages--starting out with white on the tender new growth and edges, then darkening through yellow, orange, reddish-orange, and finally a darker reddish-brown after sporulation or with age and weathering. The top of the cap also appears very shiny, almost as if it were lacquered. The fan-shaped cap can grow up to 10" wide, but more often the caps are about 4-7" wide, and there is often a stem present where the cap attaches to the wood that is up to 1" thick. The fresh pore surface is white; it gets a dirty reddish-tan with age and often supports a colony of green mold or algae. There are many cool insects and beetles that live on old Ganoderma conks, so there is really no need to remove old fruiting bodies from the wood.

Many people in the eastern part of North America where Ganoderma tsugae is abundant love to claim that Ganoderma tsugae is the true "reishi" fungus of Chinese medicinal lore, seemingly a cure for every cancer, malady, and even a fountain of youth treatment. Those same people are more than happy to try and sell some dried "reishi" to you to make a bitter decoction or some tinctured "reishi", making some pretty big promises as the efficacy of the fungus. We don't really get into medicinal fungi, but the actual "reishi" fungus is a different species--Ganoderma lucidum, and any actual scientific studies into the possible benefits of "reishi" are in regards to Ganoderma lucidum.

Very young fruiting body, sliced and pan-ready

In the spring, when the fresh growth is still white with no hint of any lacquered color showing or any signs of pores, we collect the marshmallow-y fruiting body to eat as a fresh mushroom. The mushroom should be incredibly tender--it gets tough very quickly with any hint of color or once it gets too big. The white blobs get sliced thinly, cooked with a touch of oil over medium heat until they brown, then hit with a sprinkle of salt for a taste of a mushroom that contains a lot of meaty flavor in a small slice.


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