Mystery Mollisia

[Chris Yeates]

hello all (and possibly especially someone in Jena )

as a continuation of a renewed enthusiasm for looking at discomycetes on dead herbaceous stems I have come across the following, on dead Oenanthe crocata (Hemlock Water-dropwort), which I take to be a Mollisia; there was a Pyrenopeziza sp. as well, and I will probably have a look at that tomorrow (these things use up the most valuable currency a naturalist has - time!)
the fruitbodies were (relatively) quite large and more or less uniformly mid-grey:


I cut a hand section:


these images show the make up of the various layers in the fruitbody:


the marginal cells (which I know form an important diagnostic character) were distinctively subglobose (the right hand image was produced using CombineZM):


in Lugol's Iodine granules appeared to form in the marginal cells:


ascus tips stained blue in Lugol's but quite subtlely:


I don't have an image of the spores but they were straight, narrow, more pointed towards the base and around 7.5 - 9 microns long; I neglected to note the degree of granules in the spores (although to be honest I don't recall any) I shall check tomorrow

comments (not just from Andreas) welcome

cheers

Chris

[NickCantle]

Originally Posted by Chris Yeates

comments (not just from Andreas) welcome

I'll take advantage of that and state that I'm quietly glad that I've never found any members of this genus

[FungiJohn]

Nice find Chris.

Their not too dissimilar to Mollisia revincta found on meadowsweet but then ... !!

I'm sure our man in Jena will advise

John

[mollisia]

Hallo Chris,

your Mollisia is with almost certainty Mollisia revincta. First it is the most common on herbaceous stems and second all features you show suite well. Especially the very roundish marginal cells, which are more roundish than in others species where they are +/- pear or club-shaped. Also the form of the spores with one end more pointed than the other is characteristic. They should contain one or very few tiny drops in one or both ends. You have to look at vital spores in water for that.
There is one more feature you could look at to verify: The reaction of the paraphyses when KOH is added. You have to make a preparation from the hymenium, mounted in water and only slightly squashed. The you will see a refractive vacuolar body that fills nearly the whole paraphyse. You then let KOH (2-5%) float under the cover slip from the side. Just a drop at the side of it, it will go under the cover slip by itself. At least it does when the preparation has been on the microscope for a while, because the warmness has caused an underpressure. While letting the KOH find its way under the cover slip to the preparation, you have to observe the paraphyses. When the KOH reaches them, the refractive vacuolar body will be desolved immediately. You can nearly hear it making "plopp" . This disolving can cause a yellow reaction or it can be colourless. Species as M. fusca or rosae are strongly positive, M. revincta is slightly positiv. Will say, you will observe a yellow reaction for a short time, then the yellow sap becomes more and more colourless. So if you mount directly in KOH you will not see the reaction, because it has vanished already until you come to look at the preparation.

Here are pictures from such a reaction:


weak reaction:


strong reaction:


violet reaction, an extremly rare case (undescribed species):


best regards,
Andreas

[NickCantle]

Andreas, you are simply inspiring

[FungiJohn]

Originally Posted by NickCantle

Andreas, you are simply inspiring

Hey ... What about me .... Andreas obviously read my post first

[NickCantle]

Originally Posted by FungiJohn

Hey ... What about me .... Andreas obviously read my post first

You're all inspiring to me!

[mollisia]

Originally Posted by FungiJohn

Hey ... What about me .... Andreas obviously read my post first

Hi,

I had not, otherwise I would certainly have mentioned your posting. 2 minutes for all the writing and loading up the pictures and linking them is to few time for me old man

As you I'm the opinion that M. revincta is correct and I just wanted to add, that this species is not restricted to Filipendula ulmariae, as some people think, but quite common on many different substrates - but only herbs. You will find it very common e.g. on Rubus idaeus or on Ranunculus platanifolius and aconitifolius. In fact, it seems to be the only ubiquistic species from herbaceous stems, all other species on herby are quite host specific.

best regards,
Andreas

[FungiJohn]

Originally Posted by mollisia

Hi,

I had not, otherwise I would certainly have mentioned your posting. 2 minutes for all the writing and loading up the pictures and linking them is to few time for me old man

As you I'm the opinion that M. revincta is correct and I just wanted to add, that this species is not restricted to Filipendula ulmariae, as some people think, but quite common on many different substrates - but only herbs. You will find it very common e.g. on Rubus idaeus or on Ranunculus platanifolius and aconitifolius. In fact, it seems to be the only ubiquistic species from herbaceous stems, all other species on herby are quite host specific.

best regards,
Andreas

I know Andreas

Your usual excellent explanation and images are most welcome as against my pure guess work.

Best Wishes - John

[Alantb]

I'm really impressed - I didn't know that Mollisia had been sorted out so well; all those I look at seem to be M. cinerea or anonymous [if you see what I mean]. Andreas do you have a literature ref. for the recent information - is Dennis getting out of date?
Alan