Hygroscopic Black Smudge for ID

[RobSutton]

Found this unexciting thing on a Beech twig - I was lying on the ground looking at something else at the time!



Out of curiosity I took a photo and consigned it to the pile of "odd but can't do much else with photos" I've got.

Whilst passing the same way a few days later I noticed the same branch but now the inconspicuous smudge looked like this:



It has an amazingly hygroscopic nature after a few drops of rain or even in heavy mist it absorbs water and changes appearance dramatically. On drying out in resumes it's former state. It's been doing this for about two weeks now and today I finally got a bit under the microscope. Most of it consists of clusters of chained cells on long "hyphal" stalks. There were a few other things in the mass as well, a few four pointed structures (eg top right), a few long, brown, septate tubes (eg bottom left) and a few algal cells as well but the majority were these stalked clusters.



I suspect the additional bits are red herrings (contaminants from the branch or soil) but any help with what this thing is would be much appreciated.

[nige]

Not sure but i will go for early Exidia plana for my guess

[RobSutton]

I can see where you're coming from with that one. On further research I think it must be the conidial stage of something else - but what I haven't a clue. I keep watching and hoping it will turn into something more recognisable .....

[diggleken]

Could well turn out to be Black Bulgar, Bulgaria inquinans, at an early stage Rob.
No doubt one of our microscopy experts can help better though!
Cheers
Ken

[Chris Yeates]

Hi Rob

it's a puzzle and therefore not "unexciting" at all; I think we can safely dismiss Exidia and Bulgaria here - just going on the black and rubbery-looking road is misleading

the branched multicellular jobs are what we would until recently have called hyphomycetes - I'll get back to you on these - there may be an aero-aquatic theme going on here . . .

I think I might have a name for that dark multiseptate curved conidium inset at bottom left though: it strongly resembles the Scolicosporium anamorph of the ascomycete Asteromassaria macrospora - here's one I prepared earlier :


Fagus as a substrate fits perfectly as well - if you find some more of it in better condition it should clinch it

cheers

Chris

[stickman]

Hi all

Chris is right - this is definately interesting!

In fact it forms a piece of a puzzle I've been working on..... bare with me here people - I suspect I am about to confuse myself (and you lot)

A few weeks ago I found a Nectria sp growing on Fagus:



The perithecia were emerging from a 'stroma' of olivaceous conidia:





Originally I had these down as the anamorphic state of the Nectria sp. and was going down the route of N.flavoviridis which has a greenish Fusarium anamorph. (I'm no expert on dematiaceous hyphomycetes!)

Anyway, in an effort to rule out Nectria lugdunensis (this has an aquatic Heliscus anamorph) I submerged the specimen in spring water for a few days to see if any aquatic anamorphs were produced.

I was suprised to observe many 4-5 armed pyramid-shaped conidia (exactly like the one in the top-right of Rob's pic)were being produced in amongst the original ones - like Chris says - obvously an aquatic form.

Although it is now obvious to me that the conidia do not belong to the Nectria I don't think the pyramidal forms occuring in both Rob's specimens and mine can be coincidental can they? Could they possibly be two different 'forms'of the same conidia?

As far as the Nectria goes, it's a bit easier now I know it's associated with another fungus (thanks Chris), although there don't seem to be any records of a Nectria on Asteromassaria macrospora or it's anamorph. N.episphaeria is the one most often recorded with pyrenomycetes - but there are a few others.....

Any comments welcome!

Nick.

[nige]

Sorry im just trying to grasp what you are saying here ,Is this an adaptation of one or a link between two, aquatic or airborne

[stickman]

Sorry, I could have been clearer!

I'm trying to suggest that the spore in the top right of Rob's photo and the one in the bottom left might be produced by the same species in response to different environmental conditions.

I don't have any literature that covers these type of spores but I suspect Ellis 'Dematiaceous Hyphomycetes' might include them. (I only have the second volume)

Any ideas Chris?

Cheers, Nick.

[Chris Yeates]

Originally Posted by stickman

. . . . .

I don't have any literature that covers these type of spores but I suspect Ellis 'Dematiaceous Hyphomycetes' might include them. (I only have the second volume)

Any ideas Chris?

Cheers, Nick.

I don't think Dematiaceous Hyphomycetes volumes 1 or 2 would help here, Nick; I know that the terms are taxonomically obsolete but if this is the Scolicosporium macrosporium state of Asteromassaria macrospora - and it certainly resembles it - then it's a coelomycete, not a hyphomycete; the way those conidia are being produced along a palisade of conidiogenous cells is generally very un-hypho-like

I'm assuming we're seeing a squash preparation here, with the conidia exposed by the fungal body splitting open? Sutton in The Coelomycetes says, in his generic description of Scoliciosporium:
"Conidiomata acervular, subperidermal, brown, separate, composed of pale brown, thin-walled textura angularis. Dehiscence irregular." which probably fits this fungus?

This also is not related (directly) to the Nectria in my opinion (as you correctly point out - and there's nothing like having the specimen in front of you); the teleomorph is Asteromassaria macrospora in the Pleosporales, not related to the Hypocreales at all; there are very few dematiaceous anamorphs in Nectria - most have hyaline conidia, and none to my knowledge took anything like this (though Fusarium can look a bit like this - never as pigmented, and never, I don't think, with such thick cell walls

so the relationship may be something other, possibly merely commensal on a suitable bit of rotting real estate - I'm not aware of any biological link between the two (but you never know)


I certainly think whatever is in the picture at top right is similarly nothing to do with the Asteromassaria macrospora anamorph.

A friend to whom I've sent the link (and who has done a lot of work on aero-aquatics, comments as follows: "
Re hypho …
Not enough information. I can’t see anything resembling conidia, just conidiophores, some of which look macronematous and others semi-macronematous."

which lays them to rest as far as I can see : perhaps well worth keeping an eye on and seeing what develops; this is where the professionals would be getting the agar plates out . . . .

Chris

[stickman]

Just to push the coincidence further though,

Today I collected Scoliciosporium again, on a Fagus twig from a location several miles away from the first.



And again it was accompanied by these 4-armed conidia:





And just to 'put the cherry on the cake' there was a Nectria too.

Nick.