This specimen agrees very well with the macro description given in CNALH for Buellia disciformis. The 8-spored asci and 1-septate spores with average dimensions of Me = 16.7 × 6.5 µm ; Qe = 2.6 (N=25) also fall within the values given there, though a bit shorter. It should also be mentioned that I observed some “apparently” 3-septate (i.e. with two additional false septa) spores, fact that is referred in CNALH to occur occasionally. However, The photo presented there and contrary to the description given for the surface: “pale white to ivory, dull, smooth, epruinose, phenocorticate, esorediate” shows a greenish thallus; Nevertheless, in the 1st photo of Sharnoff photos a specimen similar to mine is shown (the 2nd is the one used in CNALH). Also Irish lichens presents a photo similar to mine, but also refers bigger spores. According to CNALH the similar B. ochroleuca has a granular and darker thallus and slightly bigger spores; B. erubescens is also referred to be similar but has smaller spores and different shaped (broadly ellipsoid).
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B hyperbolica is a somewhat diferent species (see this photo at Wales-lichens) and, moreover it is a rare species (at least in UK).
About the “inspersed hymenium” it is a difficult task, at least for beginners. What I remember from the microscopy of this specimen is that the sections were particularly bad to observe and, as a consequence, I took no photos of them.
British Flora claims there is only one other epiphytic species with spores that size: B. hyperbolica. It does not have an inspersed hymenium like (B. disciformis does), and it has ±atranorin and fumarprotocetraric (K± yellow/brown, P+ orange/red). So the best discriminant is presence or lack of oil drops in hymenium, not chemistry. (Of course, that’s a character I don’t know how to read yet!)
if I can find it again.
I thought it was odd you didn’t report the spot tests!
the sample fly (literally) from my window when I intended to make the chemical tests that I didn’t made “in loco”.
Created: 2012-07-25 13:02:51 CDT (-0500)
Last modified: 2012-07-25 13:02:53 CDT (-0500)
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