When: 2014-05-24

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

Who: zaca

No specimen available

According to the British Flora in the British islands, and by extension I believe the same can happen here, there are only four Caloplaca spp. satysfying the following conditions:
- Grow on (calcareous or siliceous) rocks;
- Thallus entirely corticate without isidia, blastidia or soralia;
- Disc yellow, orange or rust coloured when dry; Thalline margin disappearing with age;
- Cortex white or grey, K- (only discs usually K+ purple)
- Ascospore septum >1/8 lenght of spore;
Namely , C. arenaria, C. ceracea, C. crenularia, C. holocarpa agg. . To note that the last one is an aggregate of taxa, that the authors consider not to be yet completely resolved.
It happens that quite recently I believe to have found three of these species, only C. arenaria being absent from those observations.

In this observation only C. crenularia is considered, the others being subject of proper observations.
In addition to the previously mentioned features, some others are:
- Grew on siliceous rock;
- A cracked areolate surface, pale grey;
- Discs red-brown coloured; Proper margins glossy, flexuose, of the same colour of the discs; Pieces of thallus adherent to apothecia;
- The layer of the green alga below the hypothecium is interrupted or inexistence at places;
- Paraphyses thin, flexuose and slightly swolen at the apices;
- Ascospores with average dimensions: Me = 14.2 × 8 um ; Qe = 1.8 (N=22); Septum with 1/3 or more than the lenght of the ascospore.

[Note: I suspect that these values are a bit inflated as a result of the addition of a drop of K to the slide.]

The habitat and the dimensions of the spores distinguishes it from C. holocarpa, The color of the apothecia and the inexistence of a entire green layer below the hypothecium distinguishes it from C. ceracea, and the wide septum of the ascospores distinguishes it from C. arenaria.
Attached one can find a set of photos illustrating all the properties mentioned above.


Chemical reactions;
Microscopy 1;: Apothecial section;
Microscopy 2: Asci and spores.

Proposed Names

87% (1)
Recognized by sight
Used references: British Flora: Smith et al. (Editors), The Lichens of Great Britain and Ireland, Bristish Lichen Society, 2nd edition, 2009.
Based on microscopic features
Based on chemical features

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= Observer’s choice
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