Physarum mutabile?

Not technically fungi, but often lumped together with fungi
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James Brown
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Physarum mutabile?

Post by James Brown » Thu Nov 17, 2016 10:04 pm

A friend has seen this organism in a pasture in Mattishall, Norfolk over the late summer and autumn. He brought it to me because I'm a plant pathologist but I think that it is in fact a myxomycete. It's on the leaves of many species of plant, monocot and dicot, over an area of about 1m diameter. Might it be Physarum mutabile?
Attachments
IMG_2852 (1024x768).jpg
Physarum mutabile(?) in pasture
Bingham1.jpg
Physarum mutabile(?) under microscope
Bingham3.jpg
Physarum mutabile(?) close-up

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Lancashire Lad
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Re: Physarum mutabile?

Post by Lancashire Lad » Sat Nov 19, 2016 2:38 pm

Hello, and welcome to UK Fungi.

Whilst your photos do exhibit typically Physarum-like macro characteristics, I think it would be difficult to give anything like a confident agreement (or otherwise) to your suggestion of P.mutabile, without having full "micro" details. (spore size/ornamentation, capillitium characteristics - nodes present or not - shape of nodes if present - pseudocolumella present or not, etc. etc.).

It's worth noting that there are presently only 13 records of P.mutabile on the FRDBI: -
http://www.fieldmycology.net/FRDBI/FRDB ... GBNum=6183 - so that species certainly (within the UK) isn't common!

From what I understand, the shape of the sporangia in P.mutabile is actually quite a good macro characteristic - and whilst Ing describes the shape as sub-globose or top-shaped, his sketch shows it with a visibly "flattened" apex (rather like a pear upside down).

I occasionally use Juana Arrabal's online gallery as a source of reference when I'm comparing or trying to ID myxo finds, and she has some good quality photos of P.mutabile (or P.mutabilis as she has titled it?), which do show the sporangia's flattened top very nicely: -
https://get.google.com/albumarchive/118 ... aIrsYDkDPA

From what I can see, your pics don't readily appear to show that feature, but perhaps you have more samples that do exhibit it?

On balance, and with so few records, unless you can confidently say that all the microscopic characteristics fit well, I'd be wary of naming it as anything more definite than a Physarum species.

Regards,
Mike.
Common sense is not so common.

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Re: Physarum mutabile?

Post by Pitufo » Sat Nov 19, 2016 6:23 pm

Hi James

If you have a sample - or can still collect one - I would be very happy to confirm the identity for you and send you the microscopy images. The same offer goes for any other myxomycetes you would like examining in the future.

Kind regards,

John

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Re: Physarum mutabile?

Post by James Brown » Sat Nov 19, 2016 11:54 pm

Thank-you, Mike, for your very helpful comments. I see what you mean about the flattened top of the sporangium. In fact, I have a picture which shows this feature quite well. I didn't post it previously because only one sporangium is in focus but the angle from which if was taken shows the flattened top nicely on this sporangium, just to the right of the centre of the picture; also on the one slightly out of focus at the top right. Is this sufficiently distinctive to identify the organism as P. mutabile?

And thank-you, John, for your kind offer to identify it by microscopy. I'll ask my friend if there are any sporangia still visible but when I saw him last week, they'd started to dissolve into a black goo. Storm Angus, which arrived in Norfolk ten minutes ago judging by the noise on the windows, won't have helped to preserve them. But I can ask. (Is "black goo" any use for identifying spores or other microscopic structures?)

If this is P. mutabile, it's close to the other reported observation in Norfolk, back in 1930. That was in grid square TG11 and my friend's field is in TG01.

Best wishes to both of you,

James
Attachments
Bingham4.jpg
P.mutabile(?) showing flattened top of sporangium

James Brown
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Re: Physarum mutabile?

Post by James Brown » Tue Nov 29, 2016 10:31 am

Pitufo wrote:Hi James

If you have a sample - or can still collect one - I would be very happy to confirm the identity for you and send you the microscopy images. The same offer goes for any other myxomycetes you would like examining in the future.

Kind regards,

John
Hi John - No, we don't think there are any more fruiting bodies in the field. But I kept a leaf (of groundsel, I think) with fruiting bodies on it and put it in a −80°C freezer. If you're willing to identify it, that would be great.

Option 1 is I could cut off a piece of leaf and send it to you first class. If so, please could you send me your address; my email is <deleted>. Will a fruiting body that's come out of a very cold freezer survive a day in transit? Should I pack it with anything, e.g. silica gel or ice or dry ice?

Option 2 is you could tell me what structures we need to look at to identify the species, then I can take it to one of the microscopists here to examine (I work in a biological research organisation). If you wish, we could try Option 1 first then move to Option 2 if the sample doesn't survive the journey; there's enough leaf material to have 2 or 3 goes at it.

Note that although I'm a plant pathologist, I'm not a taxonomist of any kind, let alone a mycologist. So your advice will be most helpful.

James
Last edited by James Brown on Tue Nov 29, 2016 11:35 am, edited 1 time in total.

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Re: Physarum mutabile?

Post by Pitufo » Tue Nov 29, 2016 11:27 am

Hi James

I have posted a bit of info on how to pack here viewtopic.php?f=8&t=1463&p=7537#p7537

Drying is fine for preservation. If you send me a sample and keep some to look at, I will post a few photos of the most important bits (spores, capillitium and lime granules, etc) and you can have a look yourself.

If you want to understand them fully then you would probably be better doing some reading - there are some very good books avaialble (see literature section).

Kind regards,

John

P.S. I have sent you an email. You should probably remove your email from the post above or you may find yourself getting a lot of unwanted correspondence.
Last edited by Pitufo on Tue Nov 29, 2016 4:50 pm, edited 1 time in total.

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Lancashire Lad
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Re: Physarum mutabile?

Post by Lancashire Lad » Tue Nov 29, 2016 1:01 pm

James Brown wrote:. . . . Is this sufficiently distinctive to identify the organism as P. mutabile? . . . .
Hi,

Sorry for late response, but I've only just spotted these additional posts.

I'm led to believe that the flattened top is a very good indicator, and the fact that you have found it near previously recorded finds bodes well, but microscopy is still necessary to conclusively determine whether or not that's what it is.

However, if you are sending samples to John, I'm sure he will be able to give you the definitive answer - as well as some of his superb photographs of the microscopic characteristics as supporting evidence! ;)

Regards,
Mike.
Common sense is not so common.

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Re: Physarum mutabile?

Post by Pitufo » Fri Dec 16, 2016 7:28 pm

Thanks James and Mike

Please find attached a few annotated photos as requested by James. Physarum mutabile looks good to me - with a couple of caveats. Firstly, the spores were very variable in size. Secondly, the lime notes on the capillitium were not as distinct as I expected them to be (and difficult to photograph - I will add some if I get some decent pics).

The overall size, shape, thickness and colour of stalk and hypothallus plus habitat seem to fit the descriptions in Ing and Poulain. Any other ID suggestions welcome of course.

It looks like a good record of a rarely-recorded species.
Attachments
Physarum mutabile 1000 with notes.jpg
Physarum mutabile sporangium with notes
Physarum mutabile cross section 1000 with notes.jpg
Physarum mutabile sporangium cross section with notes
Spores in water (JB)167unsharp.jpeg
Spores in water with measurements
sporestack20MPE600_1000x2_1000.jpg
Spores in water showing size variability

James Brown
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Re: Physarum mutabile?

Post by James Brown » Fri Dec 16, 2016 10:54 pm

Very many thanks, John. I'm not only pleased but surprised that I got my first ever attempt at identifying a myxo right (I'm not the sort of plant pathologist who spends much time identifying diseases and parasites). I wonder if some of the odd features noted by John (lime nodes, variable spores) are because the specimen was quite old; I was told the slime mould was first seen in the field in July but I didn't see it until early November.

Next question: how do I go about recording a new record and its location?

James

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Re: Physarum mutabile?

Post by Pitufo » Sat Dec 17, 2016 10:43 am

Details for your local recorder. Date, grid reference and substrate will be needed.

http://www.nnns.org.uk/content/fungus-s ... -home-page

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