Notes:
Two specimens growing on the edge of woods on the sandy shoulder of a dirt road. Both pine and oak were around, so either or both can be the host. The pair were growing in the vicinity of brown-rotted soft and moist wood.
From above, the cap of the older fruitbody reminded me of A. solaniolens; however, the yellow volval material, the short-striate cap margin, and lack of the cleft bulb eliminate this possibility. Overall this taxon is like a solaniolens- “sp-54” hybrid. It’s interesting that though large pieces of loose yellow UV material were found clinging to the stipe and bulb, the UV remnants on the cap were white. Perhaps the loss of the yellow pigment can be attributed to sunlight. Also, the PV of the larger fruitbody tore away from the stipe during the development/expansion process and its fragments wound up attached to the cap margins.
For similar observations from FPP, see obs 141696, obs 174500 (yellow UV), obs 175241 (yellow UV), obs 175243, and obs 179834 (yellow UV). Observations 174500, 175243 and 179843 were scheduled for sequencing, but no info/data have been shared to date.

Spore Data:
[20/1/1]; mounted in Melzer’s and measured in profile/side-view only (suprahilar appendage to the side).
L x W = (7.0-) 7.4~9.8 (-10.2) x (5.1-) 5.3~7.0 (-7.9) μm
L x W = 8.5 × 6.0 μm
Q = 1.30-1.50 (-1.58)
Q = 1.41
Amyloid in Melzer’s; all are ellipsoid, with 12 spores having Q values from 1.40 to 1.48, and perfectly round in cross-section.
Larger/longer spores oriented themselves much better in side-view, so it was rather difficult to avoid them and focus on finding smaller spores in proper orientation. This is a common challenge with ellipsoid spores that I discussed in obs 174500. Furthermore, for some reason these spores really liked to clump together in large clusters, leaving relatively few isolated spores with an unobstructed view and making this scope session a rather lengthy exercise. Yet, I was able to find enough smaller spores in proper orientation by searching for them specifically, and perhaps measured more of them consciously. As a result, the average spore length is slightly depressed and should perhaps be closer to 9 μm. Needless to say, my measurements were anything but random, but advantage of this targeted approach is that it allows to accurately assess the max/min length and width.

Images

Smaller fb (brown ‘crumbs’ are decayed wood)
Smaller fb (brown ‘crumbs’ are decayed wood)
Smaller fb (brown ‘crumbs’ are decayed wood)
Smaller fb (brown ‘crumbs’ are decayed wood)
Spores mounted in Melzer’s and viewed at x1000
Spores mounted in Melzer’s and viewed at x1000

Proposed Names

48% (2)
Recognized by sight
Used references: obs 174500
Based on microscopic features: Spore measurements

Please login to propose your own names and vote on existing names.

= Observer’s choice
= Current consensus

Comments

Add Comment
Hello, Rod
By: I. G. Safonov (IGSafonov)
2018-01-09 16:09:41 PST (-0800)

I just saw your proposal, and I am a little bit puzzled by it. How do the spore profile, the short-striate cap margin, and the pale lemon-yellow UV of this collection correlate with the corresponding features of solaniolens?
Your herbarium records of solaniolens at WAO feature a Pine Barrens/FPP collection – RET 610-9 – made by the Burghardts and I on August 18, 2012. I checked my MO records for that date — the are a few amanitas posted by me from that FPP trip (and I recall collecting those vouchers), but, unfortunately, the solaniolens in question is not one of them.
The thing is that I could not have IDed that collection by myself because I only became familiar with solaniolens in 2015, as per my obs 207874, and, besides, my general knowledge of amanitas left much to be desired in 2012. I don’t know if the Burghards made the identification, but I suspect, Rod, that the ID is likely to be yours. I wonder if the spore profile of the 2012 FPP collection fits solaniolens, i.e., if they are globose/subglobose.
Now that I am more familiar with solaniolens, after having collected it at least 3 times last year, I can attest to the fact that I have never come across it in the NJ Pine Barrens… Seems like an unusual habitat for it!

We need to make sure that these get in the queue eventually.
By: R. E. Tulloss (ret)
2017-12-18 18:07:25 PST (-0800)

R

Just saw…
By: Dave W (Dave W)
2017-12-18 16:49:32 PST (-0800)

this one obs 303401. Looks kinda similar to me… margin short striate, cap with dark center and the appearance of innate radial fibrils.

Rod,
By: I. G. Safonov (IGSafonov)
2017-12-18 12:44:35 PST (-0800)

I agree with your comments. This collection does look somewhat different from obs 174500 and has more ellipsoid spores due to large widths.
However, at the same time, the gestalt is similar to umbilicata in terms of shape & size of the fruibody, the cap color family, and the presence of yellow volval patches clinging to the stipe.
These mushrooms were growing in the open — a strip of land between the dirt road and edge of woods — and fairly close to where other suspected collections of umbilicata had been collected in prior years.
I hope that one day DNA will be able to give us a definitive answer.

The strong contrast between the center of the cap and the rest of the cap…
By: R. E. Tulloss (ret)
2017-12-18 12:22:58 PST (-0800)

is not something we’ve seen yet in the genetically similar material that I’ve called umbilicata so far. Also the spores of umbilicata that I’ve mearsure are about half elongate rather than ellipsoid.

A question: Doe MO still require quotation marks around nom. provs. and temporary codes"?

Very best,

Rod

Herbarium Rooseveltensis Amanitarum (RET) has received specimen.
By: mcmacher
2017-11-02 11:01:25 PDT (-0700)

We have received the dried specimen. Thank you. It is being accessioned in Herbarium Rooseveltensis Amanitarum as RET 802-6.

Spore measurements & pix posted
By: I. G. Safonov (IGSafonov)
2017-09-14 22:24:19 PDT (-0700)
Very interesting…
By: Dave W (Dave W)
2017-09-14 04:48:32 PDT (-0700)

how the spores of this solaniolens-like taxon are so different from solaniolens.

Dave,
By: I. G. Safonov (IGSafonov)
2017-09-13 20:29:56 PDT (-0700)

Actually, these were fairly small and quite fragile mushrooms. The large fb in better shape had the cap diameter of only 4.3 cm, as evidenced by the spore print. I didn’t take any measurements prior to drying the material, but I estimate the large fb was identical in size to that of obs 174500 (same stage of development and matching cap size!), which I also believe is the same species. Looking at the dimensions of solaniolens reported in Rod’s website, this mushroom is of the right size for it. There is no doubt in my mind, however, that 290361 is not solaniolens — the spores of this collection are ellipsoid to elongate (will post measurements later).
As of the striations, these were quite real and observed in both fbs. Since the material was fresh and there was no evidence of drying of the cap margin, it appears to be a natural trait. Marginal striations can also been seen in at least some of the observation I list in the notes.

Reminds me of solaniolens.
By: Dave W (Dave W)
2017-09-13 19:53:50 PDT (-0700)

But the yellow uv material does seem unusual for this species. The marginal striations may be the result of the cap drying out a bit, causing the pileus to shrink and form depressions between the lines of gill attachment. I have seen this with amerirubescens… and also (uncommonly) in section Phalloideae with Destroying Angels. This mushroom would be quite large/robust for solaniolens.