The genus Solenopsora (Lichenized Ascomycetes, Leprocaulaceae ) in Italy

Guttová, A. & Nimis, P. L.: The genus Solenopsora (Lichenized Ascomycetes, Leprocaulaceae ) in Italy. — Fl. Medit. 31 (Special Issue): 55-65. 2021. — ISSN: 1120-4052 printed, 2240-4538 online. This paper includes a dichotomous key, descriptions and predictive distributional maps for all of the 9 infrageneric taxa of the lichen genus Solenopsora ( Leprocaulaceae ) known to occur in Italy. The genus includes obligatory saxicolous lichens with the main centre of diversity in the Mediterranean, Macaronesian, and Madrean biogeographical regions. All taxa have their optima below the montane belt. Most of them have a distinctly Thyrrenian-Mediterranen distribution pattern in Italy, being most frequent in areas with a mild, suboceanic climate.


Introduction
After the completion of a new checklist of the lichens of Italy (Nimis 2016), and its incorporation into ITALIC, the online information system on the lichens of Italy (Nimis & Martellos 2002;Martellos 2012), work has started on the preparation of a computer-aided lichen flora of the country, containing keys and descriptions (Nimis & Martellos 2020).A first comprehensive key, including all species known from Northern Italy (2.240 infrageneric taxa) has been already published online for testing (Nimis 2021).Separate, nationwide dichotomous keys to given families and/or genera are also being produced, which will be eventually integrated into a complete national key.
This paper is dedicated to the genus Solenopsora in Italy.It includes a key, descriptions and predictive distributional maps for all taxa known to occur in the country.The genus, for a long time listed under the Catillariaceae, was recently found to belong into the Leprocaulaceae (Miadlikowska & al. 2014, Fačkovcová & al. 2020).It mainly occurs in temperate and subtropical regions, the centre of diversity being in the Mediterranean, Macaronesian, and Madrean biogeographical regions (Fačkovcová & al. 2020).European species were treated by Guttová & al. (2014; see also Fačkovcová & al. 2019), who recognised 9 infrageneric taxa, all of which do occur in Italy (see Nimis 2016;Guttová & al. 2019).

Data and Methods
The key, which is also available online in an illustrated, interactive version, was produced using FRIDA (FRiendly IDentificAtion, see Martellos 2010), a software package for producing digital identification keys, developed since 2003 at the Department of Life Sciences of the University of Trieste.Contrary to most available software for the creation of identification tools, FRIDA is mainly focused on the optimization of classical dichotomous keys, although it also includes the possibility of adding a multi-entry query interface.FRIDA allows to store and organise characters and their states, names of taxa, descriptions, digital images, and textual notes into a unified system.These resources are used for generating digital identification keys, which can be edited, refined, enriched by further content, and published online, or used through an app for mobile devices (Martellos & Nimis 2015;Nimis & Martellos 2020).To allow collaborative efforts in the development of identification keys, FRIDA is based on a double-level architecture, which permits several authors to contribute to a common project, while maintaining a high degree of independence (Martellos 2010).
The distribution of species in the administrative regions of Italy is based on the data provided by Nimis (2016), integrated with data from Fačkovcová & al. (2019;2020), and Guttová & al. (2019).Commonness/rarity of species was assessed on the basis of the number of literature citations for the different administrative regions of Italy (from Nimis 1993Nimis , 2016)), and from the number of herbarium samples revised by Guttová & al. (2019).
The predictive distribution maps are based on the presence/absence in the administrative regions of Italy, and on commonness-rarity values (see Nimis & al. 2018) in 9 ecoregions (see Nimis 2016;Martellos & al. 2020), delimited on the basis of several thematic maps (altitude, precipitation, urbanization, etc.), also taking into account the difference between the Tyrrhenian (humid) and Adriatic (dry) part of the Italian Peninsula, which is relevant in influencing lichen distribution in Italy (Nimis & Tretiach 1995, 2004;Nimis 2016).The maps show the probability of finding a species in a given climatic area, and point to further exploration in some regions (when a species was never recorded from a region, that region remains blank).The actual distribution of species is likely to be narrower than that depicted in the maps, because these do not take into account the occurrence of the main types of rocks on which Solenopsora-species grow (calcareous, siliceous, and ultrabasic rocks).

Results
The species Solenopsora A. Massal.
Note: a Mediterranean-Atlantic, to mild-temperate species found on calcareous rocks, most often on horizontal faces.Widespread throughout Italy (Fig. 1a), with optimum below the montane belt; more heliophilous in northern than in southern Italy, where it often occurs in sheltered situations.
Flora Mediterranea 31 (Special Issue) -2021 Note: a lichen with optimum in the submediterranean belt, found in fissures of calcareous boulders in rather sheltered situations.Widespread throughout Italy (to be looked for in Umbria), but most frequent outside the Tyrrhenian ecoregion (Fig. 1b).
Note: on calcareous rocks in open to sheltered situations.Most probably widespread throughout Italy (to be looked for in several regions), with optimum below the montane belt in the Tyrrhenian part of the country (Fig. 1c).For further details see Guttová & al. (2014).
Note: a Mediterranean-Atlantic lichen found in sheltered crevices of basic siliceous rocks and on soil, especially along the coast; rare, and exclusively Tyrrhenian in Italy, to be looked for in Latium (Fig. 1d).
Note: on inclined surfaces of ultrabasic rocks (e.g.serpentine), often in fissures, in shaded situations also on vertical faces, mostly in the Mediterranean belt; so far recorded from Liguria and Tuscany (Fig. 1e).
Note: on calcareous substrata, mostly in rock fissures and in humid and shaded situations in the Mediterranean belt; so far reported only from Tuscany and Basilicata (Fig. 1f), also known from e. g. the Dalmatian coasts, Turkey, Eastern Mediterranean (Jordan), and from the Ukraine (Guttová & al. 2019).

Solenopsora olivacea
Note: on calcareous rocks, often associated with the typical subspecies, but rarer, and bound to more humid and shaded situations, with optimum below the montane belt in the Tyrrhenian part of the country (Fig. 1h). A. Massal. Lotos, 6: 75, 1856.Synonyms: Lecania holophaea var.glaucospora (Nyl.)A.L. Sm.; Lecania leucospeirea (Nyl.)A.L. Sm.; Lecanora holophaea var.glaucospora Nyl.; Lecanora leucospeirea Nyl.; Lecanora subdisparata Nyl.; Solenopsora leucospeirea (Nyl.)Zahlbr.; Solenopsora subdisparata (Nyl.)Samp.; Thalloidima leucospeireum (Nyl.)Arnold Description: Thallus crustose-subsquamulose, epilithic, pale grey to olive-grey, sorediateblastidiate, consisting of single, crowded or scattered, rarely radiating, 0.2-0.5 mm wide, squamule-like lobules with white-pruinose margins, forming irregular patches; central lobules raised and subcoralloid (1-3 mm high) when producing blastidia, apically breaking into soralialike structures; peripheral lobules adpressed and the whole finally appearing as a subleprose crust.Apothecia rare, 0.3-0.6 mm across, with an epruinose to faintly pruinose, pinkish brown to finally brown-black, flat to convex disc, and a crenulate, finally often excluded thalline margin.Epithecium brown or reddish brown; hymenium colourless, 50-60 µm high; paraphyses mostly simple, 1.5-2 µm thick, the apical cells 4-5 µm wide, often with an internal brown cap; hypothecium colourless to orange-brown, 80-110 µm high.Ascospores at first 1-celled, later 1-septate, hyaline, ellipsoid, 9-11(-14) × 4-5(-6) µm.Spot tests: thallus K+ faintly yellow, C-, KC+ faintly yellow, P-or P+ yellow-orange, UV-.Chemistry: terpenoids, unidentified substances, occasionally atranorin in low quantities, Note: a Mediterranean-Atlantic lichen found on basic siliceous substrata, including brick walls, in open to most often sheltered situations; so far reported only from Tyrrhenian Italy (Fig. 1i).olivacea (51/33), S. grisea (33/33), S. holophaea (29/17), S. vulturiensis (20/18), S. olivacea subsp.olbiensis (13/11), S. liparina (4/10), S. marina (3/1).The most commonly collected/recorded species are those which are not restricted to the eu-Mediterranean belt, the rarer species are strictly Mediterranean and often coastal, or, as in the case of S. liparina, restricted to a rather rare type of rocks (ultrabasic siliceous rocks).The species of Solenopsora have a remarkable similarity in their climatic requirements, with more specific requirements in terms of microclimate.All of them have optima below the montane belt; only S. candicans, S. cesatii and S. grisea occasionally occur above 1.000 m.Furthermore, 75% of the total number of citations, and 73% of herbarium samples are from administrative regions facing the Thyrrenian sea, the majority of species being most frequent in Thyrrenian Italy, an ecoregion characterized by a milder, more suboceanic climate than the one prevalent in northern Italy and along the Adriatic side of the Peninsula at comparable altitudes (the most relevant exception being S. cesatii, which is most frequent outside Tyrrhenian Italy).This agrees well with the model based on climatic and geological data developed by Guttová & al. (2019), suggesting that the occurrence of Solenopsorataxa seems to be mainly governed by low variability in diurnal temperature and tolerance to dryness, with precipitation in the range of 0-20 mm in the driest month and a minimum temperature of >5 °C in the coldest month.The predictive distribution maps of Fig. 1 also highlight exploration bias, as most of the taxa are undercollected.Further sampling will contribute to a better knowledge of the geographic as well as climatic areas occupied by these taxa in Italy.