Observation 32465: Amanita ocreata Peck

When: 2010-01-24

Collection location: San Mateo, California, USA [Click for map]

Who: Tom (LanLord)

No specimen available

Multiple large oak trees in the vicinity of the Japanese Garden, several lactarius in the same area.

Whiter than I’m used to seeing, but doesn’t have the voluminous volva that Ocreata would have. The volva was fairly small and closely compressed onto the bottom of the stipe.

Proposed Names

83% (1)
Recognized by sight: volva is variable in appearance. white cap makes it far more likely to be ocreata; white forms of phalloides are quite rare. next time you are in doubt, cut the mushroom in half lengthwise…ocreata often shows hollow chambers w/in its context: http://mushroomobserver.org/18686?search_seq=1224167

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
There were two
By: Tom (LanLord)
2010-01-24 16:03:45 CST (-0500)

specimens present (and possibly some “eggs” that I overlooked).

Unfortunately I can’t break out the microscope on these yet. This issue is being addressed, but I don’t have it at this time.

true, there are apparently sometimes white phalloides…
By: Debbie Viess (amanitarita)
2010-01-24 15:19:33 CST (-0500)

but they are extremely rare.

phalloides season in Central CA is ending whereas the ocreata season is just coming on (several nice specimens were brought into the FFSC Fair two weeks ago), so either is theoretically possible. Was it a single specimen? That is more common with ocreata, too.

I have found slender as well as the more commonly robust white ocreata before. I selectively hunt for amanita here in CA, and have never seen a white phalloides, even thought phalloides can fruit in the hundreds, and a white version would stand out like the proverbial sore thumb. Else Vellinga found one on UCB campus once, and apparently Mike Wood found a patch somewhere.

But if I found a white amanita section phalloides in central California in late January I would think ocreata until proven differently.

But, all colored amanitas here can show white forms, so anything is possible.

AS to the chambered stipe of ocreata…it is not present in every form I checked, but I have never seen this feature in phalloides.

phalloides vs. ocreata
By: R. E. Tulloss (ret)
2010-01-24 13:57:50 CST (-0500)

My correspondents have emphasized to me that A. phalloides (white specimens) occur with non-white A. phalloides or where the “normal” A. phalloides normally grows.

I’m not sure that cavities in the central cylinder of the stipe are a constant difference between phalloides and ocreata.

I’d go for a check via microscope.


A. Ocreata
By: Tom (LanLord)
2010-01-24 13:07:37 CST (-0500)

These were certainly whiter than I expected for Phalloides, so Ocreata is probably a better fit, they just seem to put up a significantly different profile than So. Cal. Ocreata. The general size is smaller, the volva is smaller, they were not as robust at all. In So. Cal. these things are huge.

Created: 2010-01-24 11:44:40 CST (-0500)
Last modified: 2011-03-29 15:01:14 CDT (-0400)
Viewed: 53 times, last viewed: 2017-09-06 18:30:47 CDT (-0400)
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