Observation 31389: Agaricus subsubensis Kerrigan

Which Agaricus is this?

Red staining, no odor.


[admin – Sat Aug 14 02:05:00 +0000 2010]: Changed location name from ‘Purisima Creek Redwoods Open Space Preserve, San Mateo Co., USA’ to ‘Purisima Creek Redwoods Open Space Preserve, San Mateo Co., California, USA



Proposed Names

7% (5)
Recognized by sight: no clue as to species, tho, other than, with the red staining, section sanguinolenti.
38% (5)
Used references: Calphotos shows this species under redwood. Photo by the late Dr. Orr here:
59% (2)
Recognized by sight: See comment

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Agaricus subsubensis?
By: Rick Kerrigan (rwkerrigan)
2010-01-06 13:49:02 MST (-0700)

This thing looks untidy enough to be A. subsubensis, a species I named early this year in Mycologia. Shaggy stipe and cap, underwhelming annulus, cespitose habit, pallid. The red staining in A. subsubensis is primarily a surface discoloration, rather than in the flesh, which is a fairly unusual character. The type locality is in a sandy yard south of Palm Springs, CA. However, it was also collected once under Monterey Cypress in Monterey County, CA. I have seen a published photo from Mexico that appears to be the same species. If I’m correct, the Purisima creek collection would be only the 4th known collection. Was it preserved? If so, I’d enjoy studying the collection. I don’t have the photos handy on this page but I seem to recall there was sandy soil present — interesting?
A. subsubensis, the ugly little spud, is fairly closely related to A. bitorquis, based on ITS DNA sequences.

back to Agaricus…
By: Debbie Viess (amanitarita)
2010-01-05 11:30:07 MST (-0700)

benesii is listed as having a conifer duff habitat. don’t redwoods qualify?

at any rate, they have been documented by the Orrs under redwood before.

this is probably not Agaricus arorae, which looks very different, fruits very early in the season and stains yellow in KOH as well as reddens. Applying KOH to the cap would tell the tale.
apparent lack of odor doesn’t really omit benesii, since odor varies within both the mushroom and the nose smelling it! as Allen described it (and the grass shows it to be), the size does seem to be a bit small for benesii…and it’s not like we’ve been lacking for rain!

I just sent a message to Rick Kerrigan. perhaps he will comment on this curious Agaricus.

would whoever voted “promising” on Amanita (sic) benesii please lower their vote…
By: Debbie Viess (amanitarita)
2010-01-05 11:17:37 MST (-0700)

then I can destroy the name, an obvious typo!!!

KOH on cap cuticle
By: Nathaniel Segraves (nlsegraves)
2010-01-05 10:55:47 MST (-0700)

If this turns yellow than we could have A. arorae. It is would fit the light brown cap, reddening, redwood habitat, and indistinct odor.

If Redwoods…
By: Nathaniel Segraves (nlsegraves)
2010-01-05 10:52:37 MST (-0700)

were the only trees than I agree with Debbie that benesii is not likely.

She who makes the typo, makes the call….
By: R. E. Tulloss (ret)
2010-01-05 09:20:58 MST (-0700)


I think you made a little typo. :-)

Can you please ask our beloved administrators to blow away the name “Amanita benesii”?

I guess this is the way rumors of new names begin…

Very best,


why not dry it, Allen?
By: Debbie Viess (amanitarita)
2010-01-05 08:25:53 MST (-0700)

If really no odor, and very small, may well not be benesii.

By: Alan Rockefeller (Alan Rockefeller)
2010-01-05 03:16:51 MST (-0700)

The nearest trees were redwood. The sample will be around for a day or 2 more if microscopy is needed.

By: Nathaniel Segraves (nlsegraves)
2010-01-04 16:25:53 MST (-0700)

What trees were around where you found these. They look like A. benesii. However, they should have a strong “mushroom” smell.

Created: 2010-01-02 21:17:16 MST (-0700)
Last modified: 2016-04-12 17:14:25 MDT (-0600)
Viewed: 287 times, last viewed: 2018-08-07 02:31:47 MDT (-0600)
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