You scratch my back and I’ll scratch yours.

While neither may have an itch (or even fingernails for that matter), two organisms find themselves needing each other.

Guess it is good to be needed, and even better to find the yin to your yang. Some mushrooms I recently observed in the middle of a path in the woods at Felix Neck find themselves in a relationship, and it’s complicated. Popping up in the sandy soil, a few tiger’s eye mushrooms seemingly stood alone.

But below the surface, a benevolence blossomed. Tiger’s eye mushrooms are ectomycorrhizal, meaning that they form a symbiotic relationship with tree roots under the ground. That relationship serves both organisms. The tree is supported through the uptake of minerals from the mushroom, while the mushroom benefits by getting carbohydrates or sugars from the tree roots.  

An ectomycorrhizal mushroom entwines its fungal threads, called hyphae, around the cells of its partner plant, though never entering the individual cells of the plant. This hyphae sheath is called a Hartig Net and doesn’t damage or destroy those cells because it surrounds them instead of penetrating them.

Contrast this to the more well-known actions of saprophytic mushrooms. Saprophytes live on dead organic materials and break down plant matter. The clear difference is that the former needs a live partner and the latter works on a dead one.

Even though cohabitating with underground root systems, the ectomycorrhizal mushrooms grow from soil, specifically sandy and acidic soils; hence their location on the dry, grainy trail. They prefer to coexist with conifers and mixed forests, so look for them among oaks, beech, chestnut and especially pine woodlands. Disturbance and fire are fine for this fungus, and it is known as a pioneer species, coming up early after severe habitat changes.

When tiger’s eye mushrooms first emerge from the ground, they live up to their name, looking much like their namesake stone. There is also a resemblance to a slice of a tree trunk, with colorful layers that look like tree ring growths. 

That early form can evolve into a more traditional-looking mushroom or continue a different way. This mushroom grows by adding hyphae, those earlier mentioned, but differently functioning filaments at the edge of the cap. Sometimes when one single mushroom meets another, hyphae grow into and around each other, resulting in fused caps. Those hugging hyphae can also grow around twigs or other natural materials.

Tiger’s eye mushrooms, Coltricia perennis, are also called perennial polypore, brown funnel polypore, and fairy’s stool mushrooms. Though an annual, perennial describes their tendency to endure, as they can be observed in winter and persist into the next spring season.

Blame or credit this longevity to the fact that it is a tough little shroom in terms of its constitution and its inedibility. Its leathery and woody texture make it a challenge to chew and difficult to digest for humans and wildlife alike.

Most sources suggest limited, if any, medical use of this mushroom, thought there was mention of a single, somewhat dated study, that showed its potential as an anti-tumor agent in mice. Clearly more for scientists to sort out in their own perennial efforts.

Or not, since the survival of the tiger’s eye is not dependent on its human benefits, associations or uses. What really matters, symbolically and symbiotically, are relationships; and the tiger’s eye mushroom has developed its own network that serves it quite well.

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown, and author of Martha’s Vineyard: A Field Guide to Island Nature and The Nature of Martha’s Vineyard.