Observation 207975: Amanita rooseveltensis Tulloss, Kudzma, & Wasilewski nom. prov.
When: 2015-06-26

Notes: A single sporocarp growing at the base of a magnificent pin oak.
Spores appear ellipsoid/broadly ellipsoid at x400. Measurements will be posted later.

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As you have seen, we got sequences or partial data back from five collections…
By: R. E. Tulloss (ret)
2017-05-25 10:13:05 CDT (-0500)

of rooseveltensis. So we now have a basis for future judgments on other probable rooseveltensis collections. A web page is partially available now:


Very best,


David’s material was sampled and submitted for sequencing a while back.
By: R. E. Tulloss (ret)
2017-02-26 20:21:07 CST (-0600)

On our current expected schedule, we will receive any sequences that are successfully derived by autumn of this year.

Very best,


Thank you, Rod
By: I. G. Safonov (IGSafonov)
2017-02-26 16:13:30 CST (-0600)

Just like most, if not all, of my mushroom collections, the objects in my personal MO icon picture came about by pure serendipity. The picture was taken at a foray in Southern Chester Co., PA, last August. During the ID session there, a gust of wind from an incoming thunderstorm blew some ID tags off the tables and I chased one of them to the low-cut stump quite a distance away. I wonder what kind of plant will grow in the curiously-shaped cavity this year. :-)
Yes, the cap is uniformly silvery “battleship-gray”. There are many silver-capped amanitas out there, most of them are fairly flimsy mushrooms in my experience (e.g., collections from Washington X-ing S.P. from last year), but this one was a very sturdy mushroom…
Did you happen to sequence Dave W’s obs 177267?

Very much obliged, Igor.
By: R. E. Tulloss (ret)
2017-02-26 15:21:44 CST (-0600)

I really like your personal MO icon. It is very distinctive.

I feel like I have seen this species before when I look at the photos with least glare on the cap, but I can’t place it. The DNA is most similar to Amanita sp-N28, but the genetic difference is significant from that species, and there is no dark disc contrasting with a more silvery gray on the cap.

One of the many question marks… Thanks again for the puzzles.

Very best,


By: I. G. Safonov (IGSafonov)
2017-02-26 14:27:38 CST (-0600)

thanks for the update. I will do my best to collect and preserve more material for you.

By: R. E. Tulloss (ret)
2017-02-26 13:33:05 CST (-0600)

1 ambiguous character in the new sequence. Rod

We were able to extend the nrLSU of this material to over 1200 characters.
By: R. E. Tulloss (ret)
2017-02-26 13:22:17 CST (-0600)

It has a few ambiguous characters (4). That’s not too bad. We still have no nrITS sequence. I still would like to see more material.


A south-facing sloped lawn…
By: Dave W (Dave W)
2017-02-03 19:52:27 CST (-0600)

about 20-30 feet from my house has annually produced between 5 and 50 (possibly more) of these, beginning in late June and ending mid to late summer.

Excellent memory, Dave
By: I. G. Safonov (IGSafonov)
2017-02-03 18:42:34 CST (-0600)

Yes, your amanita looks very similar to mine – from the color of the cap to the texture of the stipe skin down the to she shape and size of the volva. When I collected 207975, I also noted how robustly it was “built”, though it wasn’t an exceptionally large mushroom. The soil around the oak is very hard and compacted, not a place for flimsy mushrooms.

Reminds me of the “old species #17”…
By: Dave W (Dave W)
2017-02-03 18:26:30 CST (-0600)

that I find annually on my lawn. Seems to be a hickory associate, but sometimes I find these near oak. The longitudinally splitting stipe is something I see with this type. Stipe base/volva usually well buried in soil, with volva difficult to extract intact. Typically on lawns or fields near a wooded area. Spores are elliptical for this type. obs 177267 .

Very interesting, Rod
By: I. G. Safonov (IGSafonov)
2017-02-03 17:57:36 CST (-0600)

A 900 bps contiguous sequence is not too bad… I guess I am judging from my own experience with bolete LSU traces. I prefer to have the 5’ end intact over the 3’ end extending beyond the LR5 region for my boletes, as few bolete sequences in GenBank are that long. For boletes the stretch from the beginning of LSU to LR5 is ~1000 characters long. Sometimes I wonder if researches deposit trimmed sequences, not full-length raw traces. I know you like your amanita sequences to go to LR7.
A 3.5% genetic distance for intrageneric LSU sequences sounds like quite a bit of variability, but then I know little about the “acceptable variability range” for any genus. Perhaps I need to be a bit more open minded when looking at my unknown boletes and thinking about their possible generic placement based on the LSU data. :-)
As I said, I will be on a look out for this critter again, collect it at the earliest opportunity get a description written down. Both you and I already have a spore print. The oak stands in a residential area with lots of foot traffic nearby. Some of the folks down here are very “anti-fungal” – they would kick and stomp out any mushroom that comes into their field of sight. :-(

I have been able to produce a sequence starting near the very end of…
By: R. E. Tulloss (ret)
2017-02-03 16:45:43 CST (-0600)

nrITS and then extending over 900 characters into nrLSU. The best match in GenBank is to Amanita sp-GSM04. However, that is probably not very useful information because the differences occur at 54 positions (3.5% genetic distance). I have previously found a sequence that differs in 12 characters; however, this is still not suggestive that this latter species is identical to the one you collected. Also, the latter species is silvery gray with a distinct gray-black umbo.

So, the available evidence suggests what you have collected is different from anything for which I have found an nrLSU sequence.

Very best,


Thanks for the news, Rod
By: I. G. Safonov (IGSafonov)
2017-02-02 12:19:39 CST (-0600)

Yes, I remember very well where this one came from. It’s associated with a single oak and there are no other mycorrhizal trees nearby. Last year the oak didn’t produce anything as it was very dry most of the summer. I’ll be on the lookout for more examples. Was the DNA degraded, thus indicating improper drying, or was it unreadable because it’s an “intrinsic” property of this fb/organism? I’ve seen it happen with a couple of boletes, when both ITS and LSU were very fragmented and largely unreadable.

We have successfully extracted DNA from this material.
By: R. E. Tulloss (ret)
2017-02-02 11:39:44 CST (-0600)

The nrITS was not a clean read and large parts were useless.

The read for nrLSU were also not too good; however readable sections overlapped (although with some ambiguity). In it’s current condition, the nrLSU sequence does not match an sequence available to me. The sequence does show clearly that the species is not in the “penetratrix” group (i.e., not in the provisional series Penetratrices).

I’m concerned about defining a code numbered taxon based on a single sequence with ambiguities.

I hope we can get better data from future collections of this species.

Very best,


Thanks Igor,
By: groundhog
2015-08-04 15:33:28 CDT (-0500)

This material has arrived and we have accessioned it to Rod’s herbarium. We have scheduled it for DNA sequencing.

Thank you, Igor.
By: R. E. Tulloss (ret)
2015-06-28 20:58:19 CDT (-0500)


Of course,
By: I. G. Safonov (IGSafonov)
2015-06-27 22:14:20 CDT (-0500)

Rod, — all amanita collections I post on MO and preserve are yours. I will be sending you this and other material that I hope to collect after all the rain we just had some time next month…

Species of section Vaginatae with ellipsoid spores are always of interest to me.
By: R. E. Tulloss (ret)
2015-06-27 21:17:28 CDT (-0500)

I would be very interested in being able to examine some of this collection.

Very best,


Created: 2015-06-27 20:36:25 CDT (-0500)
Last modified: 2017-06-18 19:23:23 CDT (-0500)
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