Aborted Entoloma

Aborted Entoloma is both a typical mushroom and an infection of other mushrooms. As a typical mushroom, it obtains nutrients from non-living organic matter (saprobic), specifically woody debris and leaf litter. As an infection, it grows with and obtains nutrients from (parasitizes) Honey Mushroom (Armillaria mellea group). When a Honey Mushroom is infected, it forms a lumpy mass called a carpophoroid.

Aborted Entoloma is common and widespread in eastern North America in hardwood forests. It is found from mid-September through October on the ground, scattered or in groups, near decaying wood or in leaf litter. It is most often found with or near Honey Mushrooms. It is easily identified in its aborted (carpophoroid) form, and nearly impossible to identify in its mushroom form.

Mushroom
The cap is ¾″ to 3″ in diameter and convex at first. It is gray to grayish-brown, hairless, and dry. The margins are rolled under. As it ages it becomes broadly convex or flat, with or without a raised bump in the center.

The stalk is ¾″ to 3″ long and 3 ⁄16″to ⅝″ thick. It is solid, hairless or finely hairy, and sometimes somewhat enlarged at the base. The base of the stalk is covered with a white fuzz that is part of the underground, vegetative component (mycelium).

The flesh is white and dense. It is edible but difficult to distinguish from other poisonous Entolomas. For this reason, only the aborted carpophoroid version should be eaten.

The gills are pale gray at first, becoming pink due to a covering of spores. They are close and slightly run down the stalk.

The spore print is pink.

Carpophoroid
The aborted form is an irregular, often lumpy mass. It is ¾″ to 3″ high and often depressed in the middle. It is white at first, becoming brownish with age. The flesh is marbled white and pinkish. The stalk, if present, is short. There are no gills.

A carpophoroid is the above-ground structure of a fungus whose development suggests a fruiting body but stops before developing a normal mushroom shape and does not become reproductive. When this fungus was first described, it was thought that the lumpy mass was a Entoloma abortivum (then called Clitopilus abortivus) mushroom that never developed properly. Studies by Roy Walting in 1974 showed it to be a fungus parasitized by another fungus. He concluded that the aborted fruiting body was an E. abortivum mushroom parasitized by a Honey Mushroom (Armillaria mellea group). In 2001, research published in Mycologia (Czederpiltz, Daniel Linder, Thomas J. Volk, and Harold H. Burdsall, Jr. 2001) suggested that the carpophoroid is in reality a Honey Mushroom parasitized by the E. abortivum fungus. This conclusion remains controversial because Honey Mushroom is only found growing on wood and Aborted Entoloma is only found growing on the ground. If true, Volk suggests that the common name is incorrect and should be changed to Aborted Armillaria.

Hardwood forests

Mid-September through October

Sources

4, 7, 24, 26, 29, 30, 77.

Common and widespread in eastern North America

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