Observation 267575: Porina Müll. Arg.

When: 2017-01-14

Collection location: Serra de São Mamede, Portugal [Click for map]

Who: zaca

No specimen available

Growing on the bark of a pine tree.


Microscopy: Chemical reactions (x100);
Microscopy: Details (x400, in KOH+IKI);
Microscopy: Hymenium general view (x100, KOH and a mixture of congo and phloxine);
Microscopy: Hymenium (x 400, in KOH (top) and in KOH+congo red and phloxine);
Microscopy: Hymenium (x 1000, in KOH);
Microscopy: Asci in IKI (x 1000, over KOH);
Microscopy: Asci with spores (x 1000, several reagents used);
Microscopy: Asci stain (x 1000, several reagents used: KOH on the left, congo red & phloxine on top center and right, and KOH&IKI on the bottom center and right) ;

Proposed Names

29% (1)
Recognized by sight
58% (1)
Based on microscopic features
Based on chemical features

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Add Comment
Looking for a name:
By: zaca
2017-01-26 09:31:26 CST (+0800)

After analyzing thís lichen, at first, I was not able to find the genus to which it belongs. The first doubt I had was: is it lichenized?; the answer is yes and the algal cells can be seen in the photos attached. The second doubt was: apothecia or perithecia? Not simple to answer due to the tiny size of the fruit bodies; I was not able to do a section of it and, at the end, I put one entire ascoma in the slide and by the arrangement of the structures seemed perithecia-like. Going further, the asci are very similar to that of the genera Opegrapha and Enterographa, just to mention some. The asci (at least many of them), however, have a very distinguish feature: a chitinous-like ring at the apex. The spores are fusiform with pointing ends, 3-6 septate (?), hyaline with the following dimensions (mostly measured inside the asci, due to the absence of free spores):
(15) 16.1 – 20 (21.9) × (2.6) 2.9 – 3.7 (3.9) µm
Q = (4.1) 4.5 – 7 (7.5) ; N = 22
Me = 18 × 3.2 µm ; Qe = 5.7
With this data, consulting the British Flora, I was lead to the genus Porina and, particularly, to the species P. byssophila. Everything seem to match, including a K blue-grey reaction of the perithecia walls and paraphyses tips (blue-grey pigment), except that the thallus of that species is dark, contrasting with the dirty white of my specimen, and usually lives on rock. The species cited there living on bark is P. aenea, with similar spores (but only 3-septate) and no particular feature of the ascus apex is referred nor the blue-grey pigment, again with a darker thallus.
I search the internet for more information about _P. byssophila and was able to see, in Ref. 2, a close-up photo of the perithecia in a bright thallus, but this can be due to the big magnification where, in general, the colours are not accurate. I also saw, in Ref. 3, some photos of a specimen, perithecial sections and the spores, which are very similar to what I observed. At this website the spores are said to be 3-septate, but the Bristih Flora refers 3-7 septa, and this is more close to what I saw, though it also says that most specimens exhibit 3-septate ascospores. In Ref.4 one can also see photos of specimens and microscopy.
So, the question is: is this P. aenea or P. byssophila?