Black spot on leaf for identification

[lipase]

I found this nettle leaf with a fungal looking spot on it... Does anyone have any ideas about what this thing could be?

First pic is of the top of the nettle leaf:



And second pic is of the bottom of the leaf:



Any help is much appreciated, thanks!

Jack

[Chris Yeates]

hi

don't think this is fungal - there is something that looks a bit like this, the Ramularia state of Mycosphaerella superflua (will try to collect some tomorrow to show you - it's extremely common), but I don't think it's that

a clue is that whatever is happening is moving along the leaf-veins, when Ramularia-type fungi attack leaves they almost always form diseased areas in 'islands' bounded by the veins - though powdery mildews sometimes do move along them see:
Fungal Plant Parasites and its following post

cheers

Chris

[lipase]

Hi Chris,

Thanks, I will be interested to see the Mycosphaerella superflua.

Is this likely to be a viral infection then on the leaf?