Reishi Mushroom Identification Characteristics
These are the basic characteristics for identifying any type of reishi. Further down, the species is broken up so showcase the differences in types.
Ecology:
All reishi fungi are saprotrophic, meaning they feed on dead organic matter. Look for them on dead or dying trees and old stumps or logs.
The different species are particular about their host tree. Species that prefer hardwoods rarely cross the line to conifers and vice versa. Some types even limit themselves to just one or two tree types within the hardwood or conifer families.
Habitat:
Reishi only grows on wood, stumps, and logs. The tsugae species seems to prefer conifers, mainly hemlocks (tsuga means hemlock). Other species are found on hardwoods.
You won’t find this polypore growing on the ground or in fields. It is always attached to some type of wood, most often a dead stump or fallen log.
Cap:
The caps of reishi mushrooms are kidney or fan-shaped. Their coloring is reddish with a wet, lacquered appearance when young. The shiny, red-brown cap is one of the main identifying features of this mushroom.
When young, the growths are soft and oddly shaped — they aren’t at full fan-shape until they are at least a few weeks old. Young reishi look like knobs or ladles with long handles.
Much of their growth shape is determined by where they are growing. Reishi growing on the side of a tree grow outwards, horizontally. Specimens fruiting on logs often develop stems that arch to allow them to then grow horizontally.
Reishi caps rarely get larger than a foot across and an inch or two thick. They may or may not be attached to a stem. They may also start out with what looks like a stem, but as they spread out, the cap encompasses the entire specimen eliminating any supposed stem.
Many guides indicate the stem or lack of stem is a great identification feature. However, this isn’t always reliable. Stem growth, more often than not, varies based on where on the tree or log the specimen is growing. Even species that “don’t have stems” may develop them to increase the fungus’s access to sunlight and water. Or they may not grow one because they have full access to sunlight in the form it first appears.
As they age, their flesh becomes tough and the spores drop. Air currents often blow these spores to the top of the mushroom, dulling its shiny cap.
A key difference between species that can help with their identification is the color of their flesh when dried. The color ranges from white to tan to dark brown. The flesh may also have concentric textural zoning that is apparent when it is sliced.
Reproduction:
Spores come out of tiny pores on the underside of the mushroom rather than gills. This is why they’re known as polypores (poly means “many”).
Spore print:
Brown.
Time of year:
Spring to fall for all species.
Reishi season doesn’t work the same as with gilled or bolete mushrooms. They appear at a particular time of year but will remain there all year long unless harvested, eaten by slugs, or seriously decayed. The most common scenario is that they remain on the wood surface until they deteriorate so completely they fall off the tree.
It’s normal to find them dead on the ground around a stump or log or just about to fall off. This process usually takes a year but may be shorter or longer depending on the region, season, and amount of bug/slug damage.
