Growing on the ground in mixed woods @ ~ 4000 ft.
Caps up to 9.0 cm across surface.
Could not detect any distinct odor or see any color changes.
Spores ~ 6.0-6.6 X 3.0-4.0 microns, elongate and smooth.
Q(avg) = 1.73


Spores in KOH @ 1000X

Proposed Names

42% (3)
Recognized by sight
86% (1)
Based on chemical features: Confirmed by DNA; results from 2019 MycoBlitz Project.

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Add Comment
Agaricus subrufescentiodes confirmed
By: Ron Pastorino (Ronpast)
2020-11-02 20:19:04 CST (-0600)
By: Chaelthomas (Chaelthomas)
2019-11-06 03:35:50 CST (-0600)

looks like a sample i collected in the Portland woods.

By: Rick Kerrigan (rwkerrigan)
2019-11-05 20:59:56 CST (-0600)

Both stature and spore-size vary among the handful of A. subrufescentoides collections I was able to study, but not in an obvious ‘two species’ fashion. So this is a riddle for a future student.

There are factors that can affect spore number and spore size in at least some species, for example cold, and gradual desiccation. In at least one Agaricus taxon, the genetics of spore number strongly influences spore size.

Thanks again Rick,
By: Ron Pastorino (Ronpast)
2019-11-05 20:45:16 CST (-0600)

I do need to get some ITS data.
The spores on these were quite a bit more elongate than the other two collections. I see a fair amount of variation on spore Q values from different collections in your write-up of A. subrufescentoides so maybe not out of range(?).

A. subrifescentoides?
By: Rick Kerrigan (rwkerrigan)
2019-11-05 20:11:23 CST (-0600)

This looks more like A. subrufescentoides than anything else I know. It might be the southernmost documented collection of that species. ITS would be handy, and this rare species (complex?) should always be welcome in a public herbarium.

A. hondensis has a brown form but is not such a reddish-brown in my experience. This color is similar to that of A. kriegeri from the Northeast, but we don’t know that species from the West.