Earthfan

not listed

NNR - Unranked

not listed

Earthfan is a strange looking and inconspicuous but common fungus. It occurs on every continent worldwide except Antarctica, but it is almost completely absent between the latitudes of 30° north and 30° south. In the United States, it occurs east and west of the Great Plains, but it is absent from the Great Plains, where there are few woodlands, its natural habitat. It is common in Minnesota. It is often overlooked because the dark brown fruiting body blends in well with the plant litter on the forest floor.

Earthfan is found in summer and fall in coniferous, deciduous, and mixed forests, and pine plantations. It grows on the ground under pine, alder, birch, oak, beech, and poplar. It usually appears in clusters, but it may also be grouped or solitary. It has a mutually beneficial relationship (mycorrhizal) with the tiny rootlets of trees, absorbing sugars and amino acids while helping the tree absorb water. It is sometimes found lightly attached to rotting wood, suggesting that it may also get nutrients from dead or decaying wood (saprobic).

Earthfan is common in potted plants in nurseries. It is very common in nurseries that grow conifer seedlings for use in reforestation projects.

The fruiting body is a 2⅜″ to 6″ (6 to 15 cm) in diameter rosette or cluster of one to several cap-like structures.

The cap, sometimes referred to as the petal, is fan shaped to semi-circular, depressed in the center, and ¾″ to 2⅜″ (2 to 6 mm) long and wide. The color is various dark shades of brown, reddish brown, chocolate brown, or grayish brown. Occasionally it is zoned, sometimes with just a single dark band in the middle. The surface is dry and wrinkled radially. It is radially covered with short and velvety or longer and silky fibers. The margin is smooth at first, soon becoming split. It is usually also fringed. On freshly growing petals the margin is whitish.

The underside is grayish brown, clay brown, medium brown, or reddish brown. It is wrinkled and smooth, not covered with fibers. On older specimens, it is covered with elongated bumps that are more or less radially arranged. There are no pores on the underside.

The stalk, if present, is short, thin, tough, and the same color as the cap but often paler.

The flesh is thin and tough. It has a mild odor that is described as earthy. The edibility is unknown.

The spore print is purplish brown.

Stinking Earthfan (Thelephora palmata) caps are branched, coral-like. It has a strong garlicky odor when young that becomes a strong unpleasant odor with age. It is far less common.

Coniferous, deciduous, and mixed forests, pine plantations

Summer and fall

Sources

4, 24, 26, 29, 30, 77.

Common and widespread

The Thelephora terrestris in North America, which grows under both pines and hardwoods, is probably not the same as the fungus with that name in Europe, which grows only under pines. A recent molecular DNA study of the genus Thelephora (Ramírez-López et al., 2015) suggests that Thelephora terrestris as currently defined may actually be a complex of several distinct species.

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Location: Cass County