Observation 48527: Tricholoma subsejunctum Peck
When: 2009-10-10
No herbarium specimen

Notes: Old Maid Flats area.

Proposed Names

8% (2)
Used references: Arora MD.
54% (1)
Recognized by sight: Tricholoma viridilutescens is a european lookalike, possibly a synonym.

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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By: Sava Krstic (sava)
2010-07-16 02:00:11 CDT (-0400)

Irene, thanks again for the links and your further thoughts. The most comprehensive European book I have is Romano Bozac’s Encyclopaedia of Fungi (in Croatian), and he has three relevant descriptions: T. sejunctum, T. sejunctum var. coniferarum, and T. viridilutescens. The last is by far the best match for the mushrooms I found. Bozac also notes that T. subsejunctum and T. fucatum var. luteola are synonymous to T. viridilutescens.

Peck’s original description of subsejunctum
By: Irene Andersson (irenea)
2010-07-15 06:02:02 CDT (-0400)

can be found here:
Look at “Report of the State Botanist” page 53.

In “North American Flora” page 24, it’s also followed by Murrill’s interpretation of sejunctum. He seems to have applied the name on something he had seen i North America. I can’t tell that description apart from Peck’s subsejunctum, and it doesn’t fit the original descriptions or any of the species that have been interpreted as sejunctum in Europe. Perhaps that’s why some american collections of “sejunctum” look so different? I have also wondered why Peck’s subsejunctum hasn’t been recognized as a useful name, but I think I can see the reason there.

It’s true that there is some controversy around the name sejunctum in Europe.
Some mycologists have assumed that Sowerby’s sejunctum was found in a hardwood area, and gave another species that grows with pine, the name Tricholoma arvernense.
I don’t know what to think about that particular problem. Tricholoma sejunctum was described to be found in “fir plantations” and the one that grows with hardwoods is a rare species.
But it’s not impossible that Sowerby’s sejunctum included both of them..

By: Sava Krstic (sava)
2010-07-15 01:45:35 CDT (-0400)

Thank you very much, Irene. The PNW key indeed points to T. subsejunctum: the description “Cap yellow with brown gray to blackish component” fits better than
“Cap yellowish with browns, reddish brown”. On the other hand, the PNW Key Council’s MatchMaker does not mention T. subsejunctum and has three photos of T. sejunctum that to me look like the mushrooms I found. I would say the same for the photos here on MO that are taken on the West Coast (observation 26615, observation 15767, observation 4763, but not observation 6095).

From Trudell and Amiratti (Mushrooms of the Pacific Northwest): “What constitutes the ‘real’ T. sejunctum has been subject to differences of opinion and consensus has not been reached. […] our fungus could be a distinct entity”. Perhaps this entity is T. subsejunctum?

I couldn’t find a description of T. subsejunctum online.

PNW key
By: Irene Andersson (irenea)
2010-07-14 04:28:58 CDT (-0400)


leads straight to Tricholoma subsejunctum.

If Tricholoma sejunctum or arvernense exist in Oregon, look for a species that doesn’t turn yellow on the stem, instead it can have pinkish hues near the base, often resembling saponaceum, but with different cap surface, taste and smell.

Created: 2010-07-14 02:32:40 CDT (-0400)
Last modified: 2010-07-27 01:40:35 CDT (-0400)
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