When: 2014-08-23

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

Who: zaca

No specimen available

Notes:
Staurolemma omphalarioides = Physma omphalarioides = Collema omphalarioides (Basionym)

This was my first observation of this rare lichen.
It was a big population that covered most of the bark of the main trunk of a tree, Castanea sativa. I attach several photos of the specimens, the habitat and of the microscopy.

The name for it was suggested to me by a portuguese lichenologist, after my several attempts to give it a name (at first, I was convinced to be a Collema sp. but none of the known species matched the micro features). The main difficulty in reaching the name was that the spores, which initially I interpreted to be muriform, can indeed be simple, though with several oil dropplets or ornamented. Due to its rarity I could not find neither a description nor photos in the internet, except one with a close up of apothecia available at http://dbiodbs.univ.trieste.it/...
The genus Staurolemma was criated to accommodate the species S. omphalarioides and was segregated from Collema on the basis of different hymenial characters, including the asci without amyloid apical structures. Several other similar species were placed in this genus, namely S. dussii and S. weberi, these having I- reaction in the hymenium, whereas S. omphalarioides can have I+ reaction on the bases of asci as well as on the walls (see Ref. 1).

Quite recently I become aware of a paper (see Ref. 2) that intents to give an explanation to the anomalous distribution of this species, for which core zones are known: lowlands and coastal areas of the Mediterranean region and coastal parts of Norway. In relation to this paper, the question is that the place of the observation is located in the interior of Portugal, in middle part of the country, very close to the border with Spain, at an elevation of 600-700 m, and thus cannot be considered neither coastal nor lowland areas. This paper presents a very clear photo of a specimen of S. omphalarioides.

Images

2014-11-16-Revisitation
Microscopy: Thallus section;
Microscopy: Apothecial section;
Microscopy: Apothecial section (close-up);
Microscopy: Apothecial section 2;
Microscopy: Excipular zone;
Microscopy: Hymenium;
Microscopy: Asci;
Microscopy: Asci 2;
Microscopy: Spores.
2014-11-16-Revisitation: Habitat;
2014-11-16-Revisitation
2014-11-16-Revisitation
2014-11-16-Revisitation
2014-11-16-Revisitation
2014-11-16-Revisitation
2017-01-14 – Revisitation
2017-01-14 – Revisitation
2017-01-14 – Revisitation

Proposed Names

58% (1)
Used references: Ref. 1:
Per M. Jørgensen, New discoveries in the lichen genus Staurolemma Körber, Nova Hedwigia 90 (1-2) 153-159, 2010.
Ref. 2:
Mika Bendiksby, Sabrina Mazzoni, Marte H. Jørgensen, Rune Halvorsen, Håkon Holien; Combining genetic analyses of archived specimens with distribution modelling to explain the anomalous distribution of the rare lichen Staurolemma omphalarioides: long-distance dispersal or vicariance?; Journal of Biogeography, 41 (11): 2020–2031, 2014. (available at: http://onlinelibrary.wiley.com/...)
Based on microscopic features

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= Observer’s choice
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Comments

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2017-01-14 – Revisitation
By: zaca
2017-01-17 13:59:54 PST (-0800)

This winter is being particularly dry contrary to the usual rainfall time. Its consequences on this population is well visible in the photos now attached.