Collection location: Serra de Montejunto, Portugal [Click for map]
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. holocarpa is considered, the others being subject of proper observations.
In addition to the previously mentioned features, some others are:
- Grew on calcareous rock;
- A cracked areolate surface, grey on the basis and tinged of a yellow layer at the places where apothecia developed;
- Apothecia numerous and in aggregated in groups; Discs red-brown coloured; Proper margins flexuose, yellow coloured;
- The more or less continuous layer of the green alga below the hypothecium;
- Paraphyses more or less straight, swolen at the apices;
- Ascospores with average dimensions: Me = 11.7 × 7.3 um ; Qe = 1.6 (N=21); Septum with up to 1/3 of the lenght of the ascospore.
As mentioned above C. holocarpa is an aggregate of several taxa. It is a polymorphic species that can grow on almost every substrate. In the case of this observation, it grews on calcareous rock in a completely exposed situation and maybe that´s way the color of the apothecia is darker than usual. I believe that the same day I recently found C. ceracea (obervation 166160) and C. crenularia (obervation 166161) I also observed C. holocarpa growing on bark in a shaded habitat. This will be the subject of a forthcomming observation.
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