Coleosporium tussilaginis on Red Bartsia?

Plant diseases
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Coleosporium tussilaginis on Red Bartsia?

Post by JennyS » Sat Aug 20, 2016 9:02 pm

Came across a couple of rusts when looking for moth larvae on chalk grassland, Dorset - the first is on Red Bartsia, Odontites vernus. Not collected but is it Coleosporium tussilaginis?
zQ Coleosporium tussilaginis 160818 207 Odonites.jpg
zQ Coleosporium tussilaginis 160818 209 Odonites.jpg
zQ Coleosporium tussilaginis 160818 208 Odonites.jpg

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Chris Yeates
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Re: Coleosporium tussilaginis on Red Bartsia?

Post by Chris Yeates » Sun Aug 21, 2016 10:57 pm

Yes Jenny, that's it
I always think it's strange that this rust has such a wide host range - across a number of plant families, never mind species, given how host-restricted most rusts are. Odontites is, in my experience, the commonest host among the hemisparasites formerly included in Scrophulariaceae on which it occurs - now Orobanchaceae . . .

best wishes
"You must know it's right, the spore is on the wind tonight"
Steely Dan - "Rose Darling"

Paul Cannon
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Re: Coleosporium tussilaginis on Red Bartsia?

Post by Paul Cannon » Mon Aug 22, 2016 9:57 am

You may be interested to learn that the Continentals (or some of them at least, in the form of Klenke & Scholler's book Plflanzenparasitische Kleinpilze 2015) separate Coleosporium tussilaginis into a series of host-related species - and the one on Scrophulariaceae s. lat. is considered to be Coleosporium euphrasiae. If you consider that a biological species concept is appropriate for rusts, then this would seem logical. That doesn't mean necessarily that all Coleosporium on Scrophulariaceae/Orobanchaceae are referable to the same species...
If this approach is accepted throughout the rusts, the number of UK species will be substantially increased, which may or may not be a good thing.

In general I would always do a microscope preparation for rusts in addition to ID via symptoms - the latter approach is almost always right but you do get the odd surprise - and the spores are so beautiful.

All good wishes

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