Puccinia obscura

[John R]

On Woodrush, found by Dom.

Me = 31.2 x 24.1 µm ; Qe = 1.3

• This topic was modified 9 years, 3 months ago by John R.

[Keith T]

The spore sizes seem a bit big? (Me = 31.2 x 24.1 µm ; Qe = 1.3)
Ellis and Ellis have 18 – 25 x 15 – 21
Wilson & Henderson 18 – 26 x 15 – 22
Bioimages M. Stor 26 – 28 x 20.5 for one example
And an 1888 book 19 – 26 x 17 – 20
Given that, I can’t think of anything else it could be.
Any thoughts?

[John R]

Thanks Keith. I found a rounder example – it still comes out as 28.5 um. I double checked calibration and it seems OK.

[Dominique C]

Hi John

Thanks for this. Unfortunately, unless these are conidial spores(?) they do not match P. obscura or P. luzulae (the two species in E&E on wood rush). Nor do they match P. poarum. Info on P. obtusa is proving elusive (two further species which have been recorded by the BMS on wr). Of these four rusts I have found info on three of them and they all have septate spores.

http://www.fieldmycology.net/FRDBI/assoc.asp
http://www.sewbrec.org.uk/content/attachments/Rust%20fungi.pdf.

One further thought; is this one of those species with the potential to produce as many as four different types of spore?

It should be noted the finder was Gordon Beakes (Plankey Mill).

Since John asked me to post this he has reminded me of uredospores. I had mistakenly concentrated on the teliospores.

Of note, no matter how good E&E is it does not list every species recorded on any given plant.

• This reply was modified 9 years, 3 months ago by Dominique C.

[Dominique C]

Is it possible for an author to edit their own post after posting, if so how? Interesting, I have been able to edit this post but not the first (hence this additional comment).

[Keith T]

Information on Puccinia obtusa can be found in Mycologia vol 47 1955 p226

http://www.cybertruffle.org.uk/cyberliber/59350/0047/002/0226.htm

Don’t think it helps tho’.

[Dominique C]

Thanks Keith for the link. Is there a consensus that it is P. obscura? I would like to add it to Ron’s list. Cheers

[John R]

Yes, seems good to me. The spores are visually correct – just a bit larger than reported.

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