Page 1 of 1

Epilobium Rust - But Which?

Posted: Tue Jul 07, 2015 6:34 pm
by Lancashire Lad
Hi all,

Found in the front garden today, on a not quite yet in flower Epilobium montanum that had (until today) escaped the weeding regime. :D

I can't quite reconcile what's been found with any of the species that affect E.montanum.
Definitely not Puccinia epilobii, as the spores in my find aren't teleutospores.
Doesn't match Wilson & Henderson's descriptions of uredosori/Uredospore stage of Puccinia pulverulenta.

So, might this be the uredosori stage of Pucciniastrum epilobii? (Not one I've yet seen).
Just that I wouldn't call the spores (certainly on the evidence of the dry spore shot) "remotely and shortly echinulate" (as per Wilson & Henderson's description).

Most of the sori were tiny orange "pustules" (as seen in the second shot), containing "clumps" of spores. However, there were also a few scattered pulverulent sori, where the pustules had split open, leaving tiny dry mounds of spores on the surface.

Click on images to view at full size.
Sori on Epilobium montanum leaves
Sori on Epilobium montanum leaves
Sori on Epilobium montanum leaf (Close-up)
Sori on Epilobium montanum leaf (Close-up)
Spores x400 (In Air)
Spores x400 (In Air)
Spores x400 (In Water) Measured
Spores x400 (In Water) Measured
Any thoughts will be much appreciated.

Regards,
Mike.

Re: Epilobium Rust - But Which?

Posted: Tue Jul 07, 2015 8:37 pm
by adampembs
Are there any fir trees nearby?

Re: Epilobium Rust - But Which?

Posted: Tue Jul 07, 2015 8:43 pm
by Lancashire Lad
adampembs wrote:Are there any fir trees nearby?
Only at Christmas :D :oops:

Yes, I had thought about the fact that Pucciniastrum epilobii alternates with Abies grandis - but I'm clutching at straws here :lol:

Regards,
Mike.

Re: Epilobium Rust - But Which?

Posted: Tue Jul 07, 2015 10:19 pm
by Chris Yeates
Pucciniastrum epilobii, those tiny pustular uredinia are typical of the genus (it doesn't necessarily need the alternate host to perennate and spread). It will soon be appearing en masse on rosebay; and keep an eye open for it on Fuschsia bushes in gardens as well . . .
Chris

Re: Epilobium Rust - But Which?

Posted: Tue Jul 07, 2015 10:27 pm
by Lancashire Lad
Chris Yeates wrote:Pucciniastrum epilobii, those tiny pustular uredinia are typical of the genus (it doesn't necessarily need the alternate host to perennate and spread). It will soon be appearing en masse on rosebay; and keep an eye open for it on Fuschsia bushes in gardens as well . . .
Chris
Many thanks Chris.

With the coarsely echinulate spores, and the fact that there are no Abies grandis locally, I wondered if I was way off in my thinking, but the pustules fortunately kept bringing me back to Pucciniastrum epilobii.

Regards,
Mike.

Re: Epilobium Rust - But Which?

Posted: Wed Jul 08, 2015 6:48 am
by adampembs
I noticed quite a difference in the spininess of the spores between my two Nipplewort samples. The latter one was definitely more spiny. Both collected from within 50 ft of each other. I guess there is a certain amount of variation (host plant & environmental conditions?) even within the same local batch.