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Yellow Unicorn Entoloma (Entoloma murrayi)

  • Aubrey
  • Aug 4
  • 3 min read

Good evening, friends,


This week’s mushroom is the yellow unicorn Entoloma (Entoloma murrayi). I’ve wanted to write about this conspicuously conical mushroom since I found it for the first time in the Adirondacks back in July, and that was before another fortuitous encounter in the Catskills just last weekend. I’d heard about the mushroom for years, a common name like that travels (you could say it flies), and now we finally get to learn a little more about this mycological unicorn.


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Fun Facts


Why the mythical name? While the mushroom can be a unicorn in the sense that you don’t see it often, this has more to do with the horn-like projection at the top of the cap. Most Entolomas are umbonate and possess an umbo, the nipple-like projection at the center of the cap. This one is so pronounced that it would be considered acutely umbonate.


Another term to describe the feature is papillate, used when the umbo is broader and more areola-like in appearance. The only thing better than one mycological term you won’t remember is two.


The Michael Scott mnemonic device system for remembering this cap feature: outie belly button → umbilical cord → umbonate.
The Michael Scott mnemonic device system for remembering this cap feature: outie belly button → umbilical cord → umbonate.

There are several yellow Entolomas (E. murrayi, E. luteum, and E. quadratum to name a few), and they comprise a species complex of visually similar but genetically distinct fungi. In February, researchers from Japan described two new species in the complex (Entoloma kermesinum and Entoloma flavescens), which paradoxically both elucidates the complex and confounds it by adding more potential options for the yellow mushroom you found.


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Etymology


The genus Entoloma is derived from the Greek words entos, which means “inner”, and lóma which means “fringe” or “border”, and refers to the tendency of some mushrooms in the genus to have in-rolled margins of the caps (not applicable for this species, though).


The species epithet, murrayi, is named after a 19th century mushroomer from Massachusetts, Dennis Murray. Murray would go out collecting with Charles J Sprague (of Suillus spraguei and Niveoporofomes spraguei) throughout New England. They would send their collections, which amassed over 650, to Moses Ashley Curtis, an episcopal Priest and accomplished mycologist/botanist. A man presumably well-versed in both the Gospel of John and the Gospel of Mushrooms, I wish I could’ve caught one of his sermons. Curtis formally described the mushroom and named it Agaricus murrayi in 1859.


The gills are the same color as the cap, but discolor pink due to the mushroom’s pink spores.
The gills are the same color as the cap, but discolor pink due to the mushroom’s pink spores.

Ecology


The fungus is thought to be a decomposer of organic matter in the soil (saprobic). Both specimens I found this summer were growing out of moss in close proximity to a stream. They’re known to inhabit swamps and wet woods in eastern North America, down through Central America, and into the top of South America. They’re also found in eastern Asia. In the less tropical climes, they grow almost exclusively during the summer months of July, August, and September.


There are the aforementioned look-a-likes in the complex, but there are also some other species that look like this mushroom. I thought I found this mushroom back in 2022, but it turned out to be a Witch’s Hat (Hygrocybe conica). A useful tip in this instance would be to get a spore print as Entolomas have pink spores and Hygrocybes have white spores.


The look-a-like from 2022. Notice the more vibrant colors, the translucent stipe, and the less pronounced umbo.
The look-a-like from 2022. Notice the more vibrant colors, the translucent stipe, and the less pronounced umbo.

No rain in the forecast so we’ll have to make do with what we got last week. Full moon on Saturday,

Aubrey


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