FROM THE GRAVE: Weirdly Looking Mushrooms

Walking through the woods on a late October afternoon, you can feel the crisp air and smell the sharp scent of decaying leaves. The dry rustle of beech leaves in the breeze adds to the autumnal atmosphere. You take a break, sit on an old stump, and munch on an apple, soaking in the beauty of nature. But what’s that next to your seat? Is it a hand from beyond the grave? Black fingers with swollen knuckles stretch up through the leaf litter, reaching for your boots! You leap onto the stump to escape what seems like a zombie apocalypse. As you gather your courage for a closer look, you uncover the truth: it’s the Dead Man’s Finger mushroom (Xylaria polymorpha).

What is the Dead Man’s Finger?

The Dead Man’s Finger is an ascomycetous fungus. This means it produces spores in sac-like cells called asci. This eerie mushroom goes through several changes from spring to late fall and early winter. The individual “fingers” or club-shaped structures, often found in groups of three to six, emerge in spring. Initially, these fingers are a few inches long and white to dark grayish in color. During this stage, called the conidial stage, spores concentrate at the “fingertips” and are dispersed by wind or water as the mushrooms mature.

Growth and Appearance

As summer progresses, the stroma (communal fruiting bodies) grow larger, darkening to dark brown and black, sometimes with greenish or bluish tinges. By fall and early winter, the fingers can be several inches long. Cutting the stroma open reveals hard, white flesh resembling bone inside mummified skin. In this sexual reproductive phase, ascospores are produced in spore-producing cavities called perithecia near the surface of the “skin.” A black spore print confirms the presence of this spooky fungus.

Habitat and Role in the Ecosystem

Dead Man’s Finger mushrooms thrive on beech, maple, elm, locust, and apple stumps. These fungi are saprotrophic, meaning they feed on dead and dying trees. They specialize in consuming polysaccharides, like glucan, that bind cellulose and lignin together to form wood. This process leaves behind nutrient-rich, mushy material that feeds invertebrates and other creatures.

Caution for Gardeners

Experts advise against using mulch chipped from tree stumps or roots infected with Dead Man’s Finger. This fungus can cause black root rot in apple trees. Infections of X. polymorpha are more common in the eastern U.S., while X. mail is more common in the southern Appalachians.

Toxicity

All members of the Xylaria genus contain amatoxins and phallotoxins, compounds found in some of the most dangerous mushrooms in the world. Therefore, Dead Man’s Finger is not considered edible and can be extremely dangerous if consumed.