Sweet Chestnut leaf fungi

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Sweet Chestnut leaf fungi

Post by Steve » Tue May 02, 2017 8:29 pm

This tiny conidial fungus was very common on Sweet Chestnut leaves but doesn't seem to me to be in Ellis & Ellis. I'm sure it must be a common but overlooked species. The black shiny spots were up to 0.2mm across. The conidia were about 5x1 um. Can anyone help on this one please?
1 Stereo micro x45.JPG
Stereo microscope x45
2 b19 x 200.jpg
Whole FB x200
3 b19 600.jpg
4 b19 600a.jpg

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Chris Yeates
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Re: Sweet Chestnut leaf fungi

Post by Chris Yeates » Fri May 05, 2017 4:20 pm

My suggestion would be "Leptothyrium castaneae" a possible anamorph of Coccomyces dentatus.

In many respects oak and sweet chestnut are the same thing as far as many saprobic microfungi are concerned. If you search through piles of last year's oak or sweet chestnut leaves you will see obvious pale areas on many of them; on those are similar black dots to yours - these will if kept damp enough develop into one of the two Coccomyces species described in Ellis and Ellis I . . .

I found masses of such leaves in the past couple of days in North Wales, but development had not occurred as it has clearly been extremely dry there for quite a while - very unlike typical North Wales!

Whether an actual link with the Leptothyrium has been proved by molecular work I don't know.

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

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