Epilobium Rust - But Which?

[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.

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 leaf (Close-up)

Spores x400 (In Air)

Spores x400 (In Water) Measured

Any thoughts will be much appreciated.

Regards,
Mike.

[adampembs]

Are there any fir trees nearby?

[Lancashire Lad]

Are there any fir trees nearby?

Only at Christmas

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

Regards,
Mike.

[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

[Lancashire Lad]

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.

[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.