Hi David
this requires a living turgescent ascus in order to see if the spores are septate already inside the living asci. Judging from the appearance of the spores I suspect so, which would mean that it can hardly be a Micropeziza. Members of that genus I only know as having at maturity non-septate spores, i.e., spores are ejected when non-septate. Moreover, M. karstenii/poae/cornea has a high lipid content, unlike yours.

In Micropeziza the paraphyses are apically often swollen, and the VBs inside are more or less restricted to this inflated part. In your species the VBs are very elongate and reach far down. The spores are also distinctly larger than in that species.

What genus this belongs I cannot tell. Niptera could be a better alternative. You should test KOH whether it causes a yellow reaction at the moment when it comes in contact with the VBs. Niptera often shows this reaction.
Zotto

Hi Zotto,

Thank you for your valued observations.  I was afraid the identification was too easy! The fungus is very abundant in it's habitat so I will work further on getting a name for it.
Dave

Niptera excelsior is = Mollisia excelsior, which differs in much longer spores with more septa: ca. 50-85 x 3-4.5 µm, 7-septate.

david, did you restudy the specimen, particularly regarding a possible KOH-reaction?
Zotto

Hi Zotto,
I tried applying 3% KOH to a water mount but did not see any fleeting yellow colour. The specimen is now dried and the paraphyses contain only a finely granular content, quite different from the fresh condition.  The KOH instantly clears the cell, but without any colour changes.

The fungus is interesting enough that I am planning to revisit the locality and collect more, hopefully in a more mature condition. Unfortunately this requires a 2-hour car trip from home followed by two more hours in a canoe.  Only another mycologist could appreciate such an obsession!
Dave

Thank you very much for your comments Marco. None of my material is very mature, so the paraphyses may be less swollen apically than expected.  Material collected in another week or two should help in that regard.

The photos aren't very good, but do show that amount of swelling.  There is some obscure yellow colour in the KOH mount, but I don't think this is the reaction your are describing Zotto.

If the newly collected material is more mature perhaps we can get a culture and some useful sequences from it.
Dave

Surely the number of septa varies a bit but the normal case is 7 in the different collections that I have under this name in my folder on my homepage (Mollisia, monocots without crystals).

Another difference is the high lipid content in excelsior vs. a very low content in David's fungus.

When you go to Dennis 1978 the spores of N. excelsior measure 50-80 x 3-4 µm.

From David's scale I measure 28-33 x 4.7-5.2 µm. David, did you also measure the spores?

Species Fungorum does not accept Niptera but Belonium, an antiquated opinion. This index is not at all up to date in every case, although it is continuously improved, as far as I know by one person concerning all fungi (!).

An unpublished  ITS sequence of M. excelsior exists which yields Mollisia minutella as closest match (94%). But I must admit that no true Niptera (s.str.) sequence exists in GenBank.
Zotto

The yellow reaction disappears within some seconds, at least after 15 seconds or so. Simply mounting in KOH is not appropriate, but I assume you added KOH to water and watched the KOH coming in. About 30% of Mollisia species show this reaction, often very intense, and also in Niptera s.str. it occurs.

By the way, your photos are splendid!!