Milesina murariae

[Chris Yeates]

Milesina rusts all have their aecial stage on Abies (fir) trees, with the later stages on different ferns. Milesina rusts on ferns are not “rusty” as they have colourless spores which appear white under a lens.

Last week I was walking past an Asplenium fern-rich wall in suburban Huddersfield I have walked past scores of times when I decided to check out some rather unhappy looking wall-rue Asplenium ruta-muraria. There was the rust specific to the fern: Milesina murariae. The fern had found a spot where the strap-pointing (unfortunately all too prevalent around here) had partially fallen away, leaving a lime-rich micro-habitat on the normally acidic sandstone walls which dominate this part of West Yorkshire. Given the quantity of new fronds being produced the fern is clearly coping with its unwelcome tenant!

In Wales or western Scotland (and certainly not in Ireland) this would not be particularly exciting, but this is a rust with a distinctly Atlantic distribution and records in England are rare:

http://basidiochecklist.science.kew.org/BritishFungi/FRDBI/FRDBIrecord.asp?intGBNum=2616” class=”bbcode_url”>http://basidiochecklist.science.kew.org/BritishFungi/FRDBI/FRDBIrecord.asp?intGBNum=2616

This only the third record for Yorkshire. There were a fair number of infected plants, scattered along a 10 metre stretch, as well as apparently unaffected ones, so I felt justified in taking a couple of fronds as a voucher.

A little care is needed not to be confused by the whitish “indusia” covering the developing fern sori, but in these photographs you can see the difference between the elongated indusia and the smaller circular fungus sori of the urediniospore stage.

[attachment=3]Milesina murariae 30.jpg[/attachment]

[attachment=2]Milesina murariae 31.jpg[/attachment]

[attachment=1]Milesina murariae 31a.jpg[/attachment]

[attachment=0]Milesina murariae 31b.jpg[/attachment]

[Author]

Posts