Entoloma abortivum

🏷️ Description

Deep in the hardwood forests of eastern North America, a peculiar mushroom can be found lurking among the leaf litter and decaying wood. Meet Entoloma abortivum, also known as the aborted entoloma or the shrimp of the woods. This unique fungus has a fascinating history of mistaken identity and an ongoing mycological mystery!

📝 A Twisted Tale of Parasitism: For over a century, mycologists believed that Entoloma abortivum was being parasitized by the honey mushroom (Armillaria mellea). However, recent research has flipped the script! Studies suggest that Entoloma abortivum may actually be the parasite, attacking Armillaria and causing its fruiting bodies to transform into strange, lumpy, white blobs. These deformed structures—once thought to be "aborted" entolomas—are now considered to be altered Armillaria fruiting bodies.

Despite this breakthrough, mushroom hunters remain divided, as both the aborted and unaborted forms of Entoloma abortivum appear even when no Armillaria is fruiting nearby.

🌳 Habitat & Distribution

Entoloma abortivum thrives in deciduous forests, often appearing near decaying wood, logs, and stumps. It grows in scattered or gregarious formations, frequently in the company of Armillaria species. Look for it in late summer and fall, especially east of the Rocky Mountains.

🔎 Identification

1. The "Normal" Form

• Cap: 0.79 to 3.15 inches (2 to 8 cm) wide, convex with an inrolled margin, flattening with age; dry; gray to grayish-brown.

• Gills: Attached to the stem or running slightly down it; pale gray at first, turning pink as spores mature.

• Stem: 0.79 to 3.54 inches (2 to 9 cm) long, 0.20 to 0.59 inches (0.5 to 1.5 cm) thick; solid, sometimes slightly off-center, often with an enlarged base.

• Flesh: White and does not change color when cut.

• Odor & Taste: Strongly mealy (similar to grain or watermelon rind).

• Spore Print: Salmon-pink.

• Microscopic Features: Spores are 5- to 8-sided and measure 8–10 x 4–6 µm.

2. The "Aborted" Form

• Irregular, lumpy whitish blobs, ranging 0.79 to 3.94 inches (2 to 10 cm) high.

• Surface may discolor brownish with age.

• Interior white and pinkish, with a spongy texture.

• Found with or without normal Entoloma abortivum fruiting nearby.

🍲 Edibility & Caution

Both the normal and aborted forms of Entoloma abortivum are technically edible, with a mild, mealy taste. In Mexico, it is known as Totlcoxcatl (meaning "turkey wattle") due to its irregular shape.

📜 Synonyms

1. Agaricus abortivus Berk. & M.A. Curtis, Ann. Mag. nat. Hist., Ser. 3 4: 289 (1859)

2. Clitopilus abortivus (Berk. & M.A. Curtis) Sacc., Syll. fung. (Abellini) 5: 701 (1887)

3. Pleuropus abortivus (Berk. & M.A. Curtis) Murrill, Mycologia 3(6): 280 (1911)

4. Rhodophyllus abortivus (Berk. & M.A. Curtis) Singer, (1969)

Photo sources:

Photo 1 - Author: Christine Young (CC BY 4.0)

Photo 2 - Author: Caroline Amico (CC BY 4.0)

Photo 3 - Author: Dave Muska (CC BY 4.0)

Photo 4 - Author: Brian Hunt (CC BY 4.0)