Observation 75394: Amanita sect. Phalloideae (Fr.) Singer
When: 2011-09-04
No herbarium specimen

Proposed Names

47% (2)
Recognized by sight
53% (3)
Recognized by sight: A destroying agel type from section Phalloideae

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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I was just about to write on the same point that Dave just made…
By: R. E. Tulloss (ret)
2011-09-06 23:13:38 CDT (-0400)

The ring on A. magnivelaris is distinctly off-white or cream and of a felted consistency rather than being a thin membrane as in other destroying angels. Also, the base of the bulb in magnivelaris and elliptosperma is rather pointed. The substantial (and persistently) upstanding limb of the volva is a character of both magnivelaris and elliptosperma.

I have had personal experience with a poisoning case (clearly amatoxins were implicated) involving elliptosperma (in Rhode Island).


Just read ret’s online account
By: Dave W (Dave W)
2011-09-06 22:57:42 CDT (-0400)

of A. magnivelaris. I was unaware of this species. In order to get good macro info, it looks like the specimen would need to be mature enough to examine the ring. Destroying Angels can be a dime a dozen around here. But now I have a new reason to stop and have a closer look.

I agree, Dave.
By: Eric Smith (esmith)
2011-09-06 17:39:42 CDT (-0400)

That young material of A. bisporigera can have quite a limbate volva. I guess my point was more that it seemed really thick. And that along with the thick patch on the cap made me question the A. bisporigera ID.

I don’t think this is a member of section Amidella. I feel like this falls in Phalloideae; that’s why I suggested A. magnivelaris, which could have a patch of uv material on the cap like that. That species should have a more pointed bulb and a volva that is farther away from the stem than A. bisporigera. Hard to tell either way from this observation. A white form of A. phalloides? I guess it could be A. bisporigera, but I’m not so sure.

Eva, I would be great if you could find some more mature specimens and perhaps perform a KOH test on the cap.

Another thought or two or…
By: R. E. Tulloss (ret)
2011-09-06 17:12:16 CDT (-0400)

Amanita bisporigera has a firm-fleshed stipe insert in a soft-bulb. Species of sect. Amidella in the eastern U.S. have stipe that is usually totally elongating and inserted into a multilayered volva. Because of the variable nature of how much of the inner layers of the volva are left on the cap, the thickness of the volval limb will vary (as we just saw in thoroughly puzzling fashion at the COMA foray last weekend).

KOH will definitely segregate A. bisporigera from species of sect. Amidella that are too young to show the brick-red staining that is typical of MOST (not all) North American species of sect. Amidella (A. whetstoneae doesn’t stain very much, but has a very big volval sac; A. peckiana doesn’t stain very strongly, but has predominantly cylindric spores).

COnversely (sort of), one needs to be aware that the eastern U.S. has some white destroying angels that don’t stain yellow with KOH [e.g., A. magnivelaris (apparently in the northern tier of eastern states and SE Canada at least) and A. elliptosperma (apparently from at least Michigan down into the deep south…perhaps to eastern Texas)].

I think that the magic of some fairly concentrated (say 10%) KOH goes a long way most of the time because there is one heck of a lot of A. bisporigera out there. There were a lot of yellow stripes on white caps during the COMA foray…just as an example.


Young bisporigera
By: Dave W (Dave W)
2011-09-05 23:36:48 CDT (-0400)

often shows an elongated limbate volva. Here’s a quote lifted from the Amanita studies website. “The volva is limbate, with 2 or 3 lobes, reaching up to 38 mm from the base of the bulb, about 2 mm thick at the point half way between the attachment to the bulb…” Mature versions seem to lose the elongated parts of the volva; presumably it erodes.

But that large patch atop the cap is not a bisporogera trait… as far as I know.

Phalloideae vs. Amidella
By: I. G. Safonov (IGSafonov)
2011-09-05 23:13:44 CDT (-0400)

Good call, Bob. I missed the volval remains on the cap — actually in the second picture, the volval remnant’s crossection appears very thick, and I agree that A. bisporigera would never be sporting something like that. I also agree with your comment on the volval sac — it looks robust and limbate enough to place this mushroom into section Amidella, but the cap’s margins is not striate and not appendiculate, though the latter characteristic wouldn’t manifest itself at this stage, i.e. when the gills are still shrouded in the universal veil remnant.

The thick patch
By: Eric Smith (esmith)
2011-09-05 06:59:51 CDT (-0400)

of volval material on the cap is something I never see in A. bisporigera. Also, the thick, limbate volva makes me think this could be something other than A. bisporigera. Amanita magnivelaris? A drop of KOH on the cap might be telling. A. bisporigera consistently turns instantly bright yellow.

Created: 2011-09-04 19:15:24 CDT (-0400)
Last modified: 2011-09-07 13:52:49 CDT (-0400)
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