Rust on yellow flowering plant

[adampembs]

Tried to key this out but getting nowhere. I’m sure one of you guys will know it.

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[Lancashire Lad]

Hi Adam,

Nipplewort – Lapsana communis. (Prone to attack by the rust Puccinia lapsanae).

Note that leaves on mature plants look very different to the early leaves.

Photo below shows stage I aecidia (Photo taken in February this year): –

Click on image to view at full size.

[attachment=0]Puccinia lapsanae-03.jpg[/attachment]

Regards,

Mike.

[adampembs]

No so spectacular, but like this?

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[Lancashire Lad]

Hi Adam,

I think those tiny brown spots will be the uredosori.

From Wilson & Henderson: –

Aecidia amphigenous, somewhat crowded on large, roundish, purple spots, flattish, with torn, white, refiexed peridium; aecidiospores subgloboid or ovoid, nearly smooth, orange, 16-21 x 13-17µ.

Uredosori amphigenous, very minute, round, often confluent, pulverulent, chestnut-brown; uredospores globoid to ovoid, pale brown, 17-22×15-18µ, wall delicately echinulate, with 2 equatorial pores.

Teleutosori amphigenous, minute, scattered, pulverulent, blackishbrown; teleutospores ellipsoid or ovoid, scarcely constricted, chestnut-brown, 22-33 x 17-26µ, wall very delicately echinulate, pore of upper cell almost apical, of lower equatorial, pedicels hyaline, slender, short, often oblique, Auteu-form.

On leaves and stems of Lapsana communis, aecidia, March-May; uredo spores, April-June; teleutospores, June-September. Great Britain and Ireland, very common.

Regards,

Mike.

[adampembs]

Moved topic (as it is now a rust discussion 😆 )

Here are some micro shots (spores are distinctly echinulate and around 20µm diameter.)

[adampembs]

I thought Nipplewort rang a bell, I’m getting old…

http://www.fungi.org.uk/viewtopic.php?f=9&t=191&p=954&hilit=nipplewort#p954” class=”bbcode_url”>http://www.fungi.org.uk/viewtopic.php?f=9&t=191&p=954&hilit=nipplewort#p954

[adampembs]

While looking for pores in the spores, I came across this unusual hyphal structure 😆

[Chris Yeates]

adampembs wrote:

While looking for pores in the spores, I came across this unusual hyphal structure 😆

Hmmmm . . . . a mite unfair methinks 🙄

On a serious note it’s good to see that the Cotton Blue and heating is working – do you see what I mean about not only making the pores more obvious, but also staining the point of attachment of the uredospores?

Chris

[adampembs]

So the blue is the point of attachment and the pores are just unstained but easier to see?

[Author]

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