Phaeohelotium query

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John Watt
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Phaeohelotium query

Post by John Watt » Mon Jul 17, 2017 11:13 am

At Smithills Hall woods yesterday, I found some ascos growing on the bark of fallen Fagus twigs; not exceedingly rotten.

The discs are not hairy at the margin, and have minimal stipe - rather a thick tapering attachment, well less than half as long as the width of the disc. They were initially whitish cream but are yellowing on drying out. I tried to photo one showing the short stipe - (can't focus any better with digicam on stereomicroscope).

I am fairly sure it is a Phaeoheliotum, but my available literature doesn't give me many options.
B&K refers to the rounded cells in the excipulum which are present here, and occasional forking of paraphysis towards base.
The non-septate guttulate spores show a reddish reaction to Lugols and average 13 x 4.5 mc.

John

PS with some advice fro, Dragisa in Serbia, and referring to Otto Barral's key on Googledrive, I've been able to spot an ascus on a crozier - so species will be Phaeohelotium imberbe. Not on the FRDBI list so far ! ? Probably because not sought after enough.
Actually I also used Bernard Declerq's key; Belgium
Attachments
Phaeoheloiuma Smithills.v01.jpg
Phaeohelotium ascus.v01.jpg
Phaeohelotium ascus1.v01.jpg
Phaeohelotium forked paraphysis.v01.jpg
phaoeheliotum excipulum cells.v01.jpg
Phaeoheliotum crozier1.v01.jpg

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Chris Yeates
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Re: Phaeohelotium query

Post by Chris Yeates » Mon Jul 17, 2017 5:08 pm

John Watt wrote:
Mon Jul 17, 2017 11:13 am
..... so species will be Phaeohelotium imberbe. Not on the FRDBI list so far ! ?......
While I can't comment on your find, P. imberbe is on the GB list, but as a Hymenoscyphus: http://www.fieldmycology.net/GBCHKLST/g ... tGBNum=883

best wishes
Chris
"You must know it's right, the spore is on the wind tonight"
Steely Dan - "Rose Darling"

John Watt
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Re: Phaeohelotium query

Post by John Watt » Mon Jul 17, 2017 7:06 pm

Many thanks for clarifying that Chris.
I became pretty sure I had the correct ID but just felt oppressed that it might be first record for UK: a big responsibility !

I have spent the rest of the day also looking for croziers, or the lack thereof, with Hymenoscyphus albidus. So it's been a good learning curve but difficult.

Best wishes,

John

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Chris Yeates
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Re: Phaeohelotium query

Post by Chris Yeates » Mon Jul 17, 2017 8:31 pm

Hello John
yes the search for presence or absence of croziers can be a bit daunting, especially when one is starting out. I've found that with practice one can get the right sort of mount of squash - always with a small amount of tissue - to get a good view of ascus formation.

Although they are very different groups of fungi the croziers of ascos are a bit analagous to the clamps of basidios. In fact they can be easier to deal with: if you get good views you can tell whether a given asco does or doesn't have them; whereas being absolutely certain that a basidio definitely doesn't have clamps (which may be very scarce) is often a problem.

Again with practice one can sometimes surmise whether croziers are involved by careful examination of the bases of detached asci. I've found it useful to look for the distinctive "W" one often sees when there are croziers (arrowed):
Ciboria batschiana 05.jpg
(Ciboria batschiana)

Here you can see simple ascus formation:
Lachnum controversum 11.jpg
(Lachnum controversum)

Hope that helps (a bit!)
Chris
"You must know it's right, the spore is on the wind tonight"
Steely Dan - "Rose Darling"

John Watt
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Re: Phaeohelotium query

Post by John Watt » Tue Jul 18, 2017 2:54 pm

Hi again Chris,

Those are helpful pointers.
I was very wary of oversquashing the tissue after reading Otto's piece: I could easily imagine the asci being sheared off their attachments.
I find even my scalpel blade seems to fat to get a thin enough slice !

Best wishes,

John W
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mollisia
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Re: Phaeohelotium query

Post by mollisia » Tue Jul 18, 2017 7:23 pm

Hello,

the ecology mentioned would not suite well for Hymenoscyphus imberbe, which is - as I know it - a species which grows aquatic/submers or at least in very wet places. Also the shape of the fruitbody would not be characteristic for it.
The in my eyes best character of H. imberbe is the faint amyloid section a little bit higher than the attachement point of the fruitbody. You need a fairly thin section through the whole ascocarp in Melzers reagent to recognize this area and it is quite faint.
Also it would be good to see the spores in a water mount to see the oil drops inside.

best regards,
Andreas

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Re: Phaeohelotium query

Post by John Watt » Wed Jul 19, 2017 5:43 am

Hello Andreas,

Thanks: there were oil droplets all right but I did have some doubts about the habitat: these twigs were on the top of a pile of debris.
The parahyphises did have the strongly refractive contents mentioned in Declerq's treatment of the genus. Maybe I need to look through his key a bit more. Unfortunately, I had run out of time and discarded the collection yesterday.

Best wishes,

John Watt
Ormskirk

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