Elm Oyster

(Hypsizygus ulmarius)

               
Conservation Status

IUCN Red List

not listed

Elm Oyster

NatureServe

not yet assessed

Minnesota

not listed

Occurrence

Widespread but not common in eastern United States

Season

August to December

Habitat/Hosts

Hardwoods, especially elm and box elder

    Photo by Kirk Nelson

Identification

Elm oyster is a large mushroom. It is widespread but not common in eastern United States. It occurs alone or in pairs, sometimes in a small cluster of three or more. It is found from August to December growing from a branch scar or other wound high in a living hardwood tree, especially elm and box elder.

The cap is 2 to 6 in diameter. When young, the cap convex is and the margin is rolled under. The upper surface is white and smooth. As it ages it flattens out and the center becomes slightly sunken. The upper surface turns creamy buff or tan and develops cracks, forming a pattern of small scales or patches.

The stalk is stout, 2 to 4 long, and to 1 thick. It is whitish, solid, fibrous, smooth, dry, and usually hairless, sometimes finely hairy. It is attached centrally or slightly off center, and is sometimes enlarged at the base. There is no cup-like covering (volva) at the base of the stalk, and there are no remnants of a universal veil clinging to the stalk.

The flesh is firm and white. It is edible but tough.

The gills are closely spaced and whitish at first, becoming cream-colored with age. They are attached to the stem but do not run down the stem.

The spore print is white to buff.

 
Similar
Species

 


Distribution Distribution Map  

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


Comments

 


Taxonomy

Division:

Basidiomycota (club fungi)

 

Subdivision:

Agaricomycotina (jelly fungi, yeasts, and mushrooms)

 

Class:

Agaricomycetes (mushroom-forming fungi)

 

Subclass:

Agaricomycetidae

 

Order:

Agaricales (gill mushrooms)

 

Family:

Lyophyllaceae

 
Synonyms

Agaricus ulmarius

Dendrosarcus ulmarius

Lyophyllum ulmarium

Micromphale ulmarium

Pleuropus ulmarius

 
Common
Names

Elm Oyster


 

 

 

 

 

Glossary

universal veil

An egg-like structure that envelopes all or most of a developing gill mushroom. Remnants of the universal veil sometimes visible on a mature mushroom are patchy warts on the cap, a ring on the stem, and a volva at the base of the stem.

 

volva

Also called cup. A cup-like covering at the base of a mushroom stem, sometimes buried. It is the remnants of the universal veil ruptured by the mushroom pushing through. It is found on Amanita, Volvariella, and some other mushrooms.

 

       

Visitor Photos

   
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Kirk Nelson


Growing on a boxelder

  Elm Oyster   Elm Oyster

       
       
       

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Other Videos

 
  Elm Mushroom (Hypsizygus ulmarius) on Tree
Carl Barrentine
 
   
 
About

Published on Sep 20, 2010

Photographed at the Turtle River State Park, North Dakota (12 September 2010).

 
     
  Elm Mushroom (Hypsizygus ulmarius) on Boxelder
Carl Barrentine
 
   
 
About

Published on Sep 20, 2010

This specimen was found growing 5 meters from the ground. Photographed at the Turtle River State Park, North Dakota (19 September 2010). Go here to learn more about this species: https://www.youtube.com/redirect?q=http%3A%2F%2Fwww.mushroomexpert.com%2Fhypsizygus_ulmarius.html&redir_token=oZnTZUyQLFWY2FAuIgLZVcAA7CV8MTUwOTI4MTM3NEAxNTA5MTk0OTc0&event=video_description&v=w3TFrMESkDY

 
     
  Elm Oyster foraging - Hypsizygus ulmarius
Corie Mushrooms
 
   
 
About

Published on Nov 10, 2015

This is me. Unsuccessfully being able to reach the common. but illusive, Elm Oysters.

 
     
  Elm Oyster wild mushroom
RedFree100
 
   
 
About

Published on Nov 1, 2011

Elm Oyster is a Edible wild mushroom but tough https://www.youtube.com/redirect?redir_token=yRR8iZwUoc0P_jTrCsLUJ5Z32uR8MTUwOTI4MTU3M0AxNTA5MTk1MTcz&v=9CIv19tI6aY&q=http%3A%2F%2Fwww.gabodabuilding.com%2FMoreMushrooms.html&event=video_description

 
     

 

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Visitor Sightings

   
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Kirk Nelson
9/10/2017

Location: Lebanon Hills Regional Park

Growing on a boxelder

Elm Oyster


     
     
 

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