Growing in a small park with mostly pine.
Cap 8.0 cm across and stipe 17.5 cm long.
Stem partially hollow.
Spores ~ 10.0-14.0 X 9.3-14.0.microns, globose to subglobose.
This one looks similar to
which I found in the same park a couple of years ago.
With the small umbo and also some large spores, it seems to suggest A. penetratix or something close.


Spores in congo red @ 1000X

Proposed Names

29% (1)
Recognized by sight
82% (1)
Based on chemical features: The DNA sequences suggest that this is novel in the informal series “Penetratrices.” See comments.

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= Observer’s choice
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Add Comment
Thanks again Rod….
By: Ron Pastorino (Ronpast)
2019-12-24 23:59:14 CST (-0600)

There may be another example from 2 years earlier and from the same location
Not sure if it is in your queue.

The genes say this is not peneteratrix. It’s about 5% genetically distant from trygonion.
By: R. E. Tulloss (ret)
2019-12-24 17:29:13 CST (-0600)

However, it’s in the penetratrix group because it has the typical preface to the nrLSU gene (“TCTGACC…” etc.).

The stark white of the cap is something I haven’t seen in penetratrix which always seems to have fine gray or brown radial lines on the cap although they may be faint or irregularly disposed.

This is something not represented by DNA in GenBank or in Roosevelt. Another characteristic of this particular collection is that we were able to derive an nrITS sequence; however, we got only a scrap of the nrLSU gene.

I hope we see another one of these critters in the future. NICE FIND.

Happy Holidays and a good 2020!

Very best,


The voucher material for this observation has been accessioned in the Roosevelt herbarium.
By: R. E. Tulloss (ret)
2019-07-25 10:56:46 CDT (-0500)

We expect the material to be sampled for DNA sequencing within 48 hours.

Very best,