Observation 210431: Amanita stirps Crocea


Collectors: Abe V. Cohen, Joe Cohen
Environment: mixed grasslands and Betula (Birch)
Substrate: Sandy soil, piled up next to hole in ground being excavated for small fence post
Odor: indistinct
Taste: Slightly sweet, with very slight bitter aftertaste in about 30-60 secs.
Gills free
Cap of one mushroom has trace of universal veil
Stipe hollow, partly filled with cottony substance
Geolocation from iPhone


collection location; mushrooms came from pile of dirt in middle; note small Betula in the grass
grid is 0.5 cm x 0.5 cm
Copyright © 2015 Athena Wu
fragment of volval sac at 100x
Copyright © 2015 Athena Wu
fragment of volval sac at 100x
Copyright © 2015 Athena Wu
fragment of volval sac at 100x

Proposed Names

28% (1)
Recognized by sight
-2% (2)
Recognized by sight
61% (2)
Eye3 Eyes3
Based on microscopic features: See R. E. Tulloss Comment, “The package has arrived.” 2015-07-28 10:01:00 PDT (-0700)

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Joe, thank you for posting the images of the “strips of wallpaper”… EDITED
By: R. E. Tulloss (ret)
2015-07-28 23:55:57 EDT (-0400)

taken by Athena.

I like the first image because it show the bottom strip very clearly. The alignment of the hyphae on the strips is very clear, and the thinness of the strips is also quite clear. The combination of the three shots show two of the strips we observed today.

Very best,


You’re very welcome, Joe.
By: R. E. Tulloss (ret)
2015-07-28 17:37:00 EDT (-0400)


Thanks for the follow-up
By: Joe Cohen (Joseph D. Cohen)
2015-07-28 13:09:30 EDT (-0400)

Rod, Athena, and Naomi:

Thank you so much for following up and for the detailed report.

When I receive Athena’s photomicrograph, I will post it as you suggest.

I hope you have better luck with the DNA extraction than with the spores.

—Joe Cohen

The package has arrived. Thank you, Joe.
By: R. E. Tulloss (ret)
2015-07-28 13:01:00 EDT (-0400)

We received the package and we hoped that we could find spores to distinguish the proper section by amyloidity of spores. However, we found no mature spores on the material. From your images, I thought the species might belong in Amanita stirps Crocea. These taxa have a very thin layer of of the cap’s skin left on the inner surface of the volval sac. It tends to peel off like wallpaper coming off a wall. Since the cap’s skin is composed of radially oriented hyphae, the wallpaper on the inside of the volva is composed of vertically oriented hyphae.

Naomi Goldman and Athena Wu used a 100x dissecting scope to look at the inside of a fragment of the volval sac. Sure enough, the wallpaper was peeling off in strips! Athena got a great photo through the dissecting scope showing two of the strips of “wallpaper.” You can see the strong longitudinal orientation of the hyphae in the wallpaper. Athena will send the image to you; and you can post it to MO on this page if you would like. Please credit Athena as the photographer if you use the image.

This was an interesting exercise. I was led to think of Amanita stirps Crocea by the cap color, the short marginal striations on the cap, and the absence of section Amidella in Norwegian and Icelandic checklists. The absence of pigmented stipe decoration eliminates A. crocea. The association with birch suggests A. flavescens rather than the more Mediterranean-associated A. subnudipes.

We have scheduled the material to be sampled for DNA.

Very best,


By: groundhog
2015-07-28 12:59:33 EDT (-0400)

We have received the material and accessioned it to Rod’s Herbarium. We have scheduled it to be sequenced.

A. islandica in Sveppabókin
By: Joe Cohen (Joseph D. Cohen)
2015-07-22 13:08:52 EDT (-0400)

1. Here is a better link to an English (Google Translate) description of Sveppabókin: https://translate.google.com/...
2. English (Google Translate) description of the author: https://translate.google.com/...
3. The Amanita species described and/or illustrated in Sveppabókin are: A. arctica, A. crocea, A. muscaria, A. nivalis, A. phalloides A. vaginata, A. virosa, and A. morteni.
4. For your interest and amusement, here is what the author says about A. arctica, plus a Google Translation. So possibly A. arctica, A. nivalis, or A. icelandica, depending on whether they are different species:

Snæsakur Amanita arctica / nivalis
Stór og stæðilegur sveppur, oftast alhvítur og vex til fjalla.
Hetta 3-8 sm, oftast hvít, þo stundum gulleit á barði og grágul eða brúnleit a kúf, jafnan með gráleitum flyksum, einkum a kúf.
Stafur heldur styttri og sverari en á gráserk, hvítur, oft flösuhæður;
steið vanalega útblásin og áberandi, með nokkuð reglulegum flipum og situr studum nokkra sm uppi á stafnum, gránar með aldri.
Gro eins og á uf. tegund.
Vex til fjalla, einkum í snjóldældum og móum með grasvídi, og myndar trúylega svepprót með honum. Nokkuð tíður á Vestfjörðum og Noður- og Austurlandi, hæðarbinilu 500-750 m y.s. Jafnan stakur. Ágúst-sept.
Vegna stærðar er þetta sá sveppur svem oft er mest áberandi í snjoldældum. Tegundin hefur gengið undir ýnsum nöfnum; sumir vilja aðgreina A. arctica (hyperborea) og A. nivalis (Knudsen & Borgen 1987). Sé það mögulegt eru báðar tegundir lílega hér a fjöllum A. islandica, sem J. Melot frumlýsti nýlega eftir eintaki héðan, er lílega sama tegund og A. arctica.

Snær’s Field Amanita Arctica / nivalis
Big and handsome fungus, usually alhvítur and grows to discuss.
Hoodia [cap?] 3-8 cm, usually white, sometimes yellowish on the beat and grágul or brownish a KUF, usually with greyish flyksum, especially a KUF.
Sticking [stipe?] but shorter and wider than the gráserk [A. vaginata], white, often flösuhæður;
Steidl usually bloated and pronounced, with fairly regular tabs and sitting favored few centimeters above the letter, Grant with age.
Gro as the UF. type.
Grows to consider, especially in snjóldældum and moor with grasvídi [willow-grass?], and forms trúylega svepprót with him. Slightly frequent in the West Fjords and Noður- and East hæðarbinilu 500-750 m asl Always odd. August-September.
Due to the size this is the fungus svem often the most prominent snjóldældum. The species has gone under various names; some will distinguish A. arctica (hyperborea) and A. nivalis (Knudsen & Borgen 1987). If it is possible, both types of abnormal here a mountainous A. islandica, which J. Melo source declared recently a copy from here, is the same type of abnormal and A. arctica.

Icelandic macrofungi
By: Joe Cohen (Joseph D. Cohen)
2015-07-18 05:32:05 EDT (-0400)

I think there are a decent number of macrofungi in Iceland. I have seen two recently printed Icelandic mushroom guidebooks. (Unfortunately, they are both in Icelandic, which language I do not understand, except for illustrations and scientific names.) One of these, Sveppabókin (“The Mushroom Book”) by Helgi Hallgrímsson received the 2010 Icelandic Literary Award. See http://icelandreview.com/...
I will try to find a copy of Sveppabókin in the next few days and copy a list of Amanita. (The book is several hundred pages, has lots of illustrations, including photomicrographs, and seem to have a good Icelandic description of the illustrated species. But it costs about $80, which is not cost-effective for me because I do not understand Icelandic.)
I have read that only about 1% of Iceland is tree-covered, down from a max of about 25%. The forests were cleared for agriculture. But they are now trying to plant more trees.
— Joe

Should I try to preserve?
By: Joe Cohen (Joseph D. Cohen)
2015-07-18 05:16:27 EDT (-0400)

I still have this collection and — if you want — can try to preserve it for you. (But no guarantee of success — I do not have dehydrator, so will have to try air drying.)

I found reference to a checklist of Icelandic fungi.
By: R. E. Tulloss (ret)
2015-07-17 23:22:47 EDT (-0400)

But I haven’t seen a copy of it. There is at least one Amanita species named from Iceland (A. islandica). Betula is a host to a few subarctic species of section Vaginatae and a few other taxa including A. muscaria. Even when upstanding trees are absent, dwarf birch and dwarf williow are hosts to macrofungi incuding amanitas.

Very best,


Split stem
By: Joe Cohen (Joseph D. Cohen)
2015-07-17 11:19:43 EDT (-0400)

I have only iPhone + irregular web connection till 23 July. Will update notes then.
Looks to me like split stem rather than annulus. Above split stem is scaly/scurfy.
Only trees nearby are Betula 1-2.5m tall. But collection is in disturbed area where someone has made pile of sand (next to hole to accomodate short fencepost).

Now here’s something I don’t see every day…
By: Dave W (Dave W)
2015-07-17 09:26:00 EDT (-0400)

a large (presumably) mycorrhizal mushroom collected in Iceland!

Except for what may be rings on the stipes, these appear to be a species from section Amidella. But I can’t really tell if the material seen on the one stipe is truly a ring or just the result of the stipe splitting apart. Even if it these do have rings, this would not rule out section Amidella, as I believe there are a few documented annulate species.

Created: 2015-07-17 09:11:19 EDT (-0400)
Last modified: 2018-01-05 19:46:36 EST (-0500)
Viewed: 185 times, last viewed: 2018-01-23 11:20:35 EST (-0500)
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