Observation 276575: Rinodina

When: 2017-04-30

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

Who: zaca

No specimen available

Notes:
It’s hard to believe it’s another Rinodina. Nothing in its appearance made me suspect its genus classification until I had seen a wide variety of spores, and yet …

It is clear that once the genus is established, it is then the question of which species. After having consulted several times the (few) references that I have on this genus, I was not able to find a suitable species, taking into account that the spores are of Pachysporaria-type and that some lichen substance most exist causing a KOH orange/red reaction.

Here are some of its features intermixed with some comments:
- Growing on siliceous rock (granite);
- Thallus crustose, thick, formed by juxtaposition of areolas/squamules; it was observed with wet weather and probably the greenish coloration is a consequence; it appears to be old and becoming decomposing; vaguely ressemble that of some Lecania and of some Micarea;
- Apothecia mostly big, convex, black, with excluded margin; some small ones also exist with flat surface and a thalline rim lighter than the disc;
- Hymenium clear, ~90 um tall; Epithecium dark brown and Hypothecium orange/brown; while performing the K reactiion on a section some redish color appeared on the hypothecium and the margins of the apothecium (see attached photos);
- Very distinctive paraphyses: hyaline, septate, with ~2 um in width, bifurcated near the apices, with brown cap terminations of oval form with 5 × 10 um; Many species of Rinodina observed recently have similar paraphyses: R. oleae, R. oxydata, R. roboris, just to mention some.
- Asci of Lecanora-type, 8 spored;
- Spores typical of Rinodina and similar to what is usually called Pachysporaria-type, not as broad as observed, for instance, in R. atrocinerea, and closer to what I recently analyzed in the corticolous R. roboris; I got the following dimensions:
(14.4) 14.8 – 17.2 (19.9) × (8.3) 9 – 10.9 (11.7) µm
Q = (1.4) 1.5 – 1.8 (1.9) ; N = 37
Me = 16.1 × 9.8 µm ; Qe = 1.6 .

Images

Microscopy: Young asci (x1000, in KOH);
Microscopy: Apothecial sections (x100, in water);
Microscopy: Apothecial section and its KOH reaction (x100);
Microscopy: Paraphyses nd (immature) asci (x1000, in KOH);
Microscopy: Asci (x1000, in KOH);
Microscopy: Spores younger (x1000, in KOH);
Microscopy: Spores (x1000, in KOH);
Microscopy: Spores and their dimensions (x1000, in KOH).

Proposed Names

87% (1)
Recognized by sight

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Created: 2017-05-15 14:36:45 -05 (-0500)
Last modified: 2017-05-15 14:36:51 -05 (-0500)
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