When: 2011-03-29

Collection location: San Francisco, San Francisco Co., California, USA [Click for map]

Who: Erin Page Blanchard (CureCat)

Specimen available

Growing under Cypress. Odour is “mushroomy”. All areas stain pink where scraped, and turn faintly yellow in 10% KOH… This combination of colour reactions is only supposed to occur with A. arorae according to Fred Stevens California Agaricus Key , and this is clearly not that, so I am not sure what this is.


Proposed Names

30% (2)
Recognized by sight
-57% (4)
Recognized by sight: red staining, looks like a cocoa-brown ornamented partial veil.

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= Observer’s choice
= Current consensus


Add Comment
No, Cat
By: Alan Rockefeller (Alan Rockefeller)
2011-04-02 10:57:28 CDT (-0500)

Observation 62065 is from a mile north of this place. I guess this is the first time these are on MO.

I will say
By: Christian (Christian Schwarz)
2011-03-31 00:39:56 CDT (-0500)

that this discussion highlights how similar these species can be – something I never considered.
Especially when they are in the iffy size range and weathered cap/atypical veil modes… This fact is not noted anywhere in Kerrigan’s monograph, but Arora, ever perceptive, does note that they can be quite similar, except for size.

size does matter…
By: Debbie Viess (amanitarita)
2011-03-30 21:53:59 CDT (-0500)

it’s lilaceps.

By: Erin Page Blanchard (CureCat)
2011-03-30 21:27:26 CDT (-0500)

Largest cap is 8 inches across, and the tallest mushroom (seen on the far left of the first photo) is 10.5-11 inches tall, it is kind of difficult to get a precise measurement.

A. lilaceps
By: Christian (Christian Schwarz)
2011-03-30 19:58:11 CDT (-0500)

My guess is that these are large (based on the grass in the background and cypress duff around the mushrooms), suggesting A. lilaceps.

The weak KOH yellowing is only recorded by Kerrigan for A. lilaceps.

Kerrigan mentions that the veil of A. lilaceps often remains intact until full expansion.

As far as I can tell, only the brown veil patches on the fruitbody at left suggest A. fuscovelatus.

If Erin’s report about the size of these mushrooms leaves any wiggle room, and we really want to take it to the mat, the spores are longer and quite a bit wider in A. fuscovelatus than in A. lilaceps.

lilaceps does both redden and yellow…
By: Debbie Viess (amanitarita)
2011-03-30 19:40:27 CDT (-0500)

but that partial veil is a dead ringer for fuscovelatus.

young caps in fuscovelatus can be somewhat conical OR convex (most of the photos that I found online of caps of similar ages to Erin’s specimens show convex), stipes can be equal or enlarged slightly below, according to Arora in MDM. The veil in fuscovelatus also takes a long time to break, like is shown in Erin’s photo.

I see two examples of obvious fuscovelatus-esque pv in Erin’s photo: the far left one and the far right one that is breaking its veil. I can’t really see the veils in the two buttons in the middle, one way or the other.

On the other hand, how big are these puppies, anyway? If they are massive, then lilaceps is the better ID; fuscovelatus is a medium sized mushroom, with caps only up to 7 cm in width.

By: Christian (Christian Schwarz)
2011-03-30 18:29:09 CDT (-0500)

…has purply-brown pv patches, but a more floccose-fibrillose and conical cap when young, a very regular-cylindrical stipe.

Notice that the intact veil on the buttons at right is not cocoa-colored as in the larger fruitbody. This is an inconsistent feature of A. lilaceps, but a quite consistent feature of A. fuscovelatus (it’s named for it…)

you are right about this not being Agaricus arorae….
By: Debbie Viess (amanitarita)
2011-03-30 18:13:55 CDT (-0500)

which is small to medium sized, much more delicate and is one of the earliest fall fruiters.

lilaceps is colorful and HARD and pretty rare, at least north of Monterey.

By: Erin Page Blanchard (CureCat)
2011-03-30 14:50:55 CDT (-0500)

Alan said he found these (same location) a few weeks/months ago and posted it here, so I am assuming that observation 62065 is what he was referring to. Alan, is that correct?

By: Erin Page Blanchard (CureCat)
2011-03-30 14:22:55 CDT (-0500)

Well, I have the mushrooms still, but they are less nice after travel. I have a couple slight variations of this setup, but they were a pain in the ass to arrange. Also, there is no cypress in my backyard, so I don’t have any ‘natural’ background to arrange them. Do they grow in woodchips? I have woodchips…
Attempting to upload photos of the staining now, but my internet connection here SUCKS.

Oh also, I forgot to add- the annulus turns yellow where scraped or handled.

By: Christian (Christian Schwarz)
2011-03-30 14:09:38 CDT (-0500)

That combination occurs in this species, although both the yellowing and reddening are weaker than in A. arorae.

Go get more photos if there are more fruitbodies! We want options…

Agaricus vaporarius?
By: Sporulator
2011-03-30 14:07:59 CDT (-0500)

Looks a lot like Agaricus vaporarius (Syn. Agaricus cappellianus) and the habitat would fit. But that’s a European species. I dont’ know if the species is native to California: http://www.pilzkunde-ruhr.de/agaricus_vapo.html

Created: 2011-03-30 13:42:52 CDT (-0500)
Last modified: 2020-01-17 14:32:57 CST (-0600)
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