Myxo on leaf and bark

[flaxton]

I knew I shouldn't have started looking at these things
With this image from a piece of bark it looked pretty much like the previous Didymium difforme

Unfortunately it was just next to a leaf with a more substantial growth



With echinate spores up to 19.5um

I was soon lost again.

Help
Thanks

Mal

[stickman]

Hi Mal

I feel less comfortable about this one. I don't think I've ever collected a plasmodiocarpous Physarale with spinulose spores before.

Quite often with myxomycetes you can get 'massive' spores - these are anomalous and, I believe, an indication that the plasmodium has falied to separate into single cells, therefore each giant spore will have two (or more) myxamoeba inside.

If I try to ignore these, in your photo, the half-size spores seem to be about 9-10µm - would this be about right?

The spore surface is nevertheless not right for Didymium difforme or Diderma effusum IMO and the spines are clearly still apparent in the smaller spores.

Diderma deplanatum has spiny spores and the rough, dark capillitium that your photos show, and also commonly forms rings on leaf litter. According to Ing it has an orange base, but I have no experience of this species.

Over to Kevin.....

Cheers,
Nick

[flaxton]

Originally Posted by stickman

Hi Mal



Quite often with myxomycetes you can get 'massive' spores - these are anomalous and, I believe, an indication that the plasmodium has falied to separate into single cells, therefore each giant spore will have two (or more) myxamoeba inside.

If I try to ignore these, in your photo, the half-size spores seem to be about 9-10µm - would this be about right?

The spore surface is nevertheless not right for Didymium difforme or Diderma effusum IMO and the spines are clearly still apparent in the smaller spores.

Diderma deplanatum has spiny spores and the rough, dark capillitium that your photos show, and also commonly forms rings on leaf litter. According to Ing it has an orange base, but I have no experience of this species.

Over to Kevin.....

Cheers,
Nick

Thanks Nick
The spores seem to be all sizes from 7.5 - 20um and they are all covered in spines. There are a good number of the larger ones and I noticed that some of them have lines across the surface like the central one in this photo.



Don't know if that helps or hinders.

Mal

[Kevin Lawson]

Hello All,

This one has me baffled too.

Spores with a wide range of sizes are often seen when examining a fruit body that is immature, but in this case, the photographs (especially of the larger plasmodiocarp) clearly show a mature specimen. Nick’s suggestion that the larger spores are anomalous – the result of a failure to separate – seems to be borne out by the photograph showing the spore that appears to be composed of three parts.

I may be wrong, but I think that Diderma deplanatum is probably the best ID you are going to get. I have also not found this species myself, so can not speak from personal experience. One feature in favour of this as an ID is that the capillitium of Diderma deplanatum is ornamented with scattered nodules and spines which can be clearly seen in your photographs. If the larger (and smaller!) spores are ignored, then the spore size would be in the right range.

Regards,
Kevin