## 3 Results and Discussion
### Organisms on the Cross of the Inquisition limestone
Taxonomical reviews on the family _Telochistaceae_ transferred species of the genus _Caloplaca_ to the new genera _Kuettlingeria_ and _Pyrenodesmia_[54; 55]. [PERSON] et al. [56] revised the black endolithic _Caloplaca_ and reported that almost all the species shared _Trebouxia_ as a photobiont. _Caloplaca_ is a cosmopolitan lichen genus found in most xeric and mesic habitats [57]. The clones retrieved from lichen samples are shown in Table 2. The three lichens showed _Trebouxia aggregata_ as the photobiont, which confirmed that the finding of this green alga in the Cross fragments was associated to the occurrence of a lichen crust. [PERSON] et al. [56] stated that the photobiont of _Caloplaca variabilis_ and other closely related _Caloplaca_ spp. (e.g., _Caloplaca clahybaea_) was an unknown taxon of _Trebouxia_, typical of the Mediterranean area. These three lichens (among others) identified in the City Hall were also found on natural limestone outcrops, buildings and monuments [58; 59; 60; 61; 62]. Clones of other lichens (_Pyrenodesmia clahybaea, Xanthoria parietina_ and _Xanthoria_ sp.) were present in the sample of _Kuettlingeria teicholyta_, and in the _Caloplaca citrina_ group lichen were identified as being _Xanthoria parietina_ and _Xanthoria_ sp. In addition, a few fungi were retrieved from _Kuettlingeria teicholyta_ (_Pyrenidium_ cf. _actinellum_, _Phama_ sp., _Rhinoclaiella_ sp., _Ceratobasidium_ sp., and _Chaetothyriales_ sp.). Most of these fungi are lichenelous from arid habitats (e.g., _Phama_, _Pyrenidium_, _Rhinoclaiella_), as well as _Cornobotriella_ sp., associated with _Pyrenodesmia variabilis_[49; 50; 51; 52; 53; 54; 55; 56; 57; 58; 59; 60; 61; 63; 64]. Table 2 shows that a complex crustose lichen community colonizes the building facade of the Seville City Hall. This community is the result of the biological regeneration after the restoration of the Cross and facade, carried out between 2008 and 2010. The protocol consisted in mechanical cleaning of the limestone surfaces with water and natural soap and the joints were filled with lime mortar [65]. Previous studies on the efficacy of mechanical procedures and laser cleaning for removal of crustose lichens from granite showed that these methods were unable to eliminate the thalli into fissures [66; 67]. In our case, Figures 5 and 6 showed that different organisms penetrate the limestone through pitting and channels. Likely, the 2008-2010 cleaning did not affect the endolithic hyphae, which grow from the crustose lichen thalli and penetrate the porous limestone. These endolithic hyphae facilitate the subsequent recovery of the lichen community, in the same way that the roots in the soil allow the regeneration of the aerial part of the plants after harvesting. \begin{table}
\begin{tabular}{l l l l} \hline \hline
**Lichen** & **Associated Species** & **Accession Number** & **Group \({}^{*}\)** \\ \hline \multirow{8}{*}{_Kuettlingeria teicholyta_} & _Trebouxia aggregata_ & ON479841 & _Chlorophyta_ \\  & _Pyrenodesmia clahybaea_ & ON479847 & _Lichen_ \\  & _Xanthoria parietina_ & ON479846 & _Lichen_ \\  & _Xanthoria_ sp. & ON479845 & _Lichen_ \\  & _Phoma_ sp. & ON479844 & _Fungi_ \\  & _Ceratobasidium_ sp. & ON479843 & _Fungi_ \\  & _Pyrenidium cf. actinellum_ & ON479842 & _Fungi_ \\  & _Chaetothyriales_ sp. & ON479848 & _Fungi_ \\  & _Rhinoclaiella_ sp. & ON479849 & _Fungi_ \\ \hline \multirow{4}{*}{_Caloplaca citrina_ group_} & _Trebouxia aggregata_ & ON479852 & _Chlorophyta_ \\  & _Xanthoria parietina_ & ON479850 & _Lichen_ \\  & _Xanthoria_ sp. & ON479851 & _Lichen_ \\ \hline \multirow{2}{*}{_Pyrenodesmia variabilis_} & _Trebouxia aggregata_ & ON479854 & _Chlorophyta_ \\  & _Cornobotriella_ sp. & ON479853 & _Fungi_ \\ \hline \hline \end{tabular}  
* \({}^{*}\) Lichens are taxonomically classified by their fungal partner, so all lichens belong to the _Fungi_ kingdom. However, in this work we distinguish between fungi and lichens for convenience.  
\end{table}