During a phytosociological field-work campaign on the vegetation of the travertine outcrops, included in the Special Area of Conservation (SAC) “Travertini Acque Albule (Bagni di Tivoli)” (Central Italy), several taxa of particular interest were identified. Carex vulpina, Lolium apenninum, Onosma echioides subsp. angustifolia, Typha domingensis, T. laxmannii and Vicia pannonica subsp. pannonica are new for the Lazio administrative Region, while Ophrys illyrica and Zannichellia peltata are confirmed for the flora of this Region. For each of these taxa phytosociological samples describing the plant communities in which they were found are provided. New records for rare species were also reported for cryptogams such as Algae, Lichens and Mosses.

flora, Habitat Directive, landscape planning, nature conservation, phytosociology, taxonomy

The “Acque Albule” travertines have always been considered a site of great historical, archaeological and naturalistic interest. The Acque Albule plain (Fig. 1) is the largest travertine basin of Italy (about 45 km²) and has been an obliged destination for travellers on the Grand Tour since the 17th century. It is a depression on the right bank of the lower Aniene river valley that began to form about 115,000 years ago in areas of subsidence due to relaxing dynamics involving a system of transcurrent and direct faults (Faccenna 1994; Petitta et al. 2011). Due to the lithological nature of the substrate and the intense karst processes, this area exhibits an extremely varied geomorphology, characterized by travertine outcrops, sulphurous freshwaters pools and channels, petrifying springs. The Acque Albule plain was included among those identified as deserving protection in the survey of biotopes carried out by the Italian Botanical Society already in 1971 (Montelucci 1969). In 1982 the "Sorgenti Albule e Platea dei Tartari" area was included in the European Community list of “biotopes of significance for nature conservation” (code number 6559). The lithological and geomorphological characteristics of the Acque Albule plain allowed the development of a varied vegetation pattern which includes two priority habitats listed in European Interpretation Manual of the Annex I of the Council Directive 92/43/EEC: 6110* “Rupicolous calcareous or basophilic grasslands of the Alysso-Sedion albi” and 6220* “Pseudo-steppe with grasses and annuals of the Thero-Brachypodietea”. The occurrence of these two habitats brought to the institution of a Site of Community Importance (SCI, code: IT6030033) in 1995. Subsequently, two further priority habitats were identified in the SCI area (7210* “Calcareous fens with Cladium mariscus and species of the Caricion davallianae” and 7220* “Petrifying springs with tufa formation (Cratoneurion)” (Guidi 2007). In the same year Giardini (2007) put forward a proposal for the establishment of four natural monuments (which later turned out to be useful for the enlargement of the borders of the SAC). In 2019 the Site IT6030033 was designated as Special Area of Conservation (SAC). Despite its unique environmental features and the presence of four priority habitats, the Acque Albule plain has been subject to numerous tampering in the last 50 years, among which urban sprawl, industrial settlements and lowering of the water table due to the intense activity of thermal resorts and travertine extraction quarries. All these activities negatively influenced the functionality of the ecosystems (Brunetti et al. 2013). The degree of conservation of the priority habitats occurring in the SAC is rather poor and the ecosystems are strongly threatened by anthropogenic disturbance. In fact, a large part of the area is an open illegal landfill, thus the plant communities have been subject to strong fragmentation (Fig. 2). In accordance with a research project between the Monti Lucretili Regional Park (designed as SAC management authority) and the Department Planning, Design and Architecture Technology of Sapienza University, a floristic and phytosociological study started in 2021. The aim of the current project is to identify the fine-scale spatial pattern of the plant communities occurring in the SAC, assess the conservation status of those included in the list of protected habitats, and provide the basic information for drawing up the management plan.

Figure 1. 

Acque Albule Plain.

Figure 2. 

The SAC IT6030033 territory is fragmented due to the presence of urbanized areas, quarries and illegal landfill.

A comprehensive floristic-phytosociological survey of this area has never been carried out and only local contributions or investigations on specific aspects were published. Sebastiani and Mauri (1818) cited some interesting plant species for the “Solfatara di Tivoli” which is known today as Lago della Regina, while Sanguinetti (1855), drew up a list of species near the so called “Lago dei Tartari”, a sulphurous freshwater pool that no longer exists due to expansion of urbanization. Between 1882 and 1884 Pirotta, Baccarini, Canepa and Pedicino (unpublished data) performed floristic field excursions, mentioning in their notes some interesting species that have now disappeared in the Plain, such as Ophioglossum vulgatum L. (Anzalone et al. 2010). The first outline of the flora and vegetation of this area were broadly described in the middle of the last century (Montelucci 1946). The same author published many papers about flora of the travertines (Montelucci 1947; 1949; 1954; 1963), also making every effort to try to achieve its protection (Montelucci, 1969; Giardini 2004; 2008). As regards previous studies concerning the vegetation the study area was only marginally involved by phytosociological contributions, most of which mainly focusing on surrounding areas (Pignatti et al. 1961; Fanelli 1998; Di Pietro and Germani 2007; Guidi 2007; Fanelli et al. 2010; Di Pietro and Germani 2012; Di Pietro et al. 2017). Among the most recent contributions on the Acque Albule area is the phytosociological study of Fanelli (2007), on some aspects of the therophytic vegetation of travertine outcrops, a first provisional draft of vegetation map proposed by Guidi (2007); the floristic studies of on the “Montarozzo del Barco”, an anthropogenic hill of the Roman age (Giardini 2005, 2012), the landscape planning contribute of Iamonico and Di Pietro (2017) on a possible variation of the SAC boundaries. Except for an old contribute of Fiorini-Mazzanti (1857) described two new species of algae (Calothrix Jantiphora Fior-Mazz. Mss. and Hydrurus Aquae-Albulae Fior-Mazz. Mss.) on the walls of a sulphur spring channel outside the current boundaries of the SAC, no other algological, bryological or lichenological data are available for the study area. In this paper, some floristic records deriving from a phytosociological sampling field-work are presented, among which eight new records for the flora of the Lazio administrative region (six vascular plants and two bryophytes).

The Acque Albule basin is a travertine outcrop limited by three main structural elements: the Cornicolano-Lucretile-Tiburtino limestone range, the Colli Albani Volcanic system, and the Pliocenic-Quaternary subsident subcoastal area (Della Porta et al. 2017). The study area is represented by the sole territory of the “Travertini Acque Albule (Bagni di Tivoli)” SAC area. This SAC (code IT6030033) covers an area of 430.7 ha (of which 388.0 ha referring to the site originally established in 1995 and 42.7 ha referring to a subsequent enlargement). The SAC is in the Municipality of Tivoli, in the eastern sector of the Roman countryside (around 50 m a.s.l.). The original and widest surface of the SAC is bordered by: Aniene river (south and east), highway A1 south-west), via Tiburtina (north). According to the biogeographical map proposed in Natura 2000 network (https://www.eea.europa.eu/data-and-maps/figures/biogeographical-regions-in-europe-2) the SAC belong to the Mediterranean Region. More precisely it is located in an area intermediate between the Italo-Tyrrhenian biogeographical province of the Mediterranean Region and the Apennine-Balkan province of the Eurosiberian Region according to Rivas-Martίnez et al. (2002). The study area is included in the bioclimatic Transition Mediterranean Region with meso-Mediterranean thermotype and upper sub-humid umbrotype (Blasi 1994) with mean annual Temperature of 15.3° and mean annual rainfall 853 mm (Thermo-pluviometric station of Guidonia Airport located less than 5 kilometres far from the study area).

Plant collections and phytosociological sampling according to national habitat monitoring standards was conducted by using the floristic and vegetation relevé (Angelini et al. 2016, Gigante et al. 2016), which represent a basic standard also to identify and characterise typical species sensu art. 17 of the Directive 92/43/EEC (Bonari et al. 2021) in the SAC “Travertini Acque Albule (Bagni di Tivoli)” (code IT6030033) where new floristic records for both vascular plants and cryptogams were considered. The vascular plants collected in the field are preserved in the Herbarium Flaminio (HFLA; Thiers, 2022 [continuously updated]) and were identified on the basis of Pignatti (2017-2019). The nomenclature of the taxa collected follows Bartolucci et al. (2018) and Galasso et al. (2018). The collected bryophytes are kept in HFLA; Cortini Pedrotti (2001, 2005) was followed for the taxonomical identification of mosses; nomenclature follows Hodgetts et al. (2020); the species distribution in Italy refers to Aleffi et al. (2020a). Nomenclature of stoneworts follows Bazzichelli and Abdelahad (2009). Lichens have been identified in the field, using a magnifying glass. For more complex identifications, samples were collected and identified using a stereo microscope and a light microscope for microscopic diagnostic characters and chemical spot tests K (a solution of 10% potassium hydroxide), C (sodium hypochlorite solution), KC. For the identification of the lichen species several keys were used, mainly Smith et al. (2009). Nomenclature and bio-ecological characterization follows Nimis (2016).

Phytosociological sampling was carried out using the Zurich-Montpellier phytosociological approach (Braun-Blanquet 1964). For syntaxa nomenclature and syntaxonomic classification of single species at the class rank reference was made to Mucina et al. (2016).

Two hundred and twenty-four phytosociological relevés were performed between 2021 and 2022 to describe and classify the vegetation pattern of the Acque Albule basin. The coenological analysis is still in progress so that a complete classification of the plant communities will be the subject of a further paper. However, a first preliminary floristic analysis led us to the identification of several taxa of biogeographical importance among which some new records for the flora of Lazio administrative Region. For each of these new reports, one or more phytosociological relevés referring to the plant communities in which the taxa in issue were collected are presented. These relevés have been arranged in three phytosociological tables referring to the type of environment in which the taxa were found (Tab. 1, xerophilous and semi-mesophilous communities; Tab. 2, mesophilous communities; Tab. 3, hygrophilous and helophytic communities)

Vascular Plants

Amelichloa caudata (Trin.) Arriaga & Barkworth

Sida 22(1): 148 (2006).

Bas.: Stipa caudata Trin., Mém. Acad. Imp. Sci. St.-Pétersbourg, Sér. 6, Sci. Math 1: 75 (1831)

Taxon confirmed for the Lazio region and second record for Italy.

Plant native to South America (Argentina, Uruguay and Chile). This species (Fig. 3) was reported for the metropolitan area of Rome, in the Valle dell’Inferno (Anzalone 1982) which prior to our study represented the only Italian records for this species. In Galasso et al. (2018) it is classified as casual alien. Within the Acque Albule SAC Amelichloa caudata can be observed in semi-mesophilous grasslands characterized by a certain degree of anthropic disturbance. These grasslands exhibit the co-dominance of perennial grasses, such as Oloptum miliaceum, Dactylis glomerata, Avena barbata, Poa pratensis which grow together other species which are typical of disturbed clay-rich soils, such as Daucus carota and Dittrichia viscosa s.str. (Table 1 rel. 7). The most probable syntaxonomic reference is the Artemisietea class. The high degree of anthropic disturbance does not allow a certain classification at the alliance rank where similarities are found for Bromo-Oryzopsion and Inulo-Agropyrion as well. This new record confirms the slow expansion of A. caudata at the footslopes of the Lazio region sub-Apennines where it is probable that the species is now to be considered as a naturalized alien species rather than a casual alien (see Galasso et al. 2018).

Figure 3. 

Amelichloa caudata (Trin.) Arriaga & Barkworth.

Table 1.

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Xerophilous grasslands.

Relevé nb.	1	2	3	4	5	6	7
Altitude	60	59	67	67	50	51	45
Aspect	,	,	,	,	,	,	.
Slope (°)	,	,	,	,	,	,	,
Rockiness (%)	20	20	40	35	50	25	.
Stoniness (%)	25	40	20	15	15	15	15
Area (m2)	16	15	4	15	3	30	20
Cover (%)	65	60	70	70	40	80	85
Onosma echioides subsp. angustifolia communities
Onosma echioides (L.) L. subsp. angustifolia (Lehm.) Peruzzi & N.G.PassaL.	2	2	2	3	2	.	.
Ampelodesmos mauritanicus (Poir.) T.Durand & Schinz	3	3	.	.	.	.	.
Hippocrepis ciliata Willd.	1	2	.	.	.	.	.
Linum strictum L.	1	1	.	.	.	.	.
Petrosedum rupestre (L.) P.V. Heath	.	.	1	2	.	.	.
Sedum hispanicum L.	.	.	4	2	.	.	.
Reseda phyteuma L.	.	.	2	1	.	.	.
Teucrium capitatum L.	+	1	.	.	2	.	.
Cerastium glomeratum Thuill.	.	.	.	.	1	.	.
Senecio leucanthemifolius Poir.	.	.	.	.	+	1	.
Ononido-Rosmarinetea
Teucrium flavum L. subsp. flavum	+	.	.	.	.	.	.
Thymus striatus Vahl subsp. acicularis (Waldst. & Kit.) Ronniger	.	.	.	1	.	.	.
Sedo-Schleranthetea
Petrorhagia saxifraga (L.) Link	2	1	1	+	+	+	.
Campanula erinus L.	1	+	.	1	+	+	.
Daucus broteri Ten.	+	.	2	2	+	+	.
Festuca incurva (Gouan) Gutermann	2	1	2	+	1	.	.
Rostraria cristata (L.) Tzvelev	1	1	2	.	+	.	.
Saxifraga tridactylites L.	1	+	+	.	.	+	.
Sabulina tenuifolia (L.) Rchb. subsp. tenuifolia	.	+	1	+	.	.	.
Valantia muralis L.	.	.	+	+	1	.	.
Ziziphora acinos (L.) Melnikov	1	1	.	+	.	.	.
Sabulina mediterranea (Ledeb. ex Link) Rchb.	.	.	.	.	+	1	.
Aethionema saxatile (L.) R.Br.	1	.	.	.	.		.
Ajuga chamaepitys (L.) Schreb. subsp. chamaepitys		.	.	.	.	+	.
Allium sphaerocephalon L. subsp. sphaerocephalon	+	.	.	.	.	.	.
Linaria simplex (Willd.) Desf.	.	.	.	+	.	.	.
Poa bulbosa L.	.	.	.	+	.	.	.
Rostraria hispida (Savi) Doğan	.	.	.	.	1	.	.
Valerianella muricata (Steven ex M.Bieb.) W.H.Baxter & Wooster	+	.	.	.	.	.	.
Draba verna L. subsp. praecox (Steven) Rouy & Foucaud	.	.	.	.	.	1	.
Medicago minima & Festuca ligustica comm.
Medicago minima (L.) L.	.	.	.	.	.	3	.
Festuca ligustica (All.) Bertol.	.	.	.	.	.	2	.
Ophrys illyrica S. Hertel & K. Hertel	.	.	.	.	.	+	.
Stipo-Trachynetea
Helianthemum salicifolium (L.) Mill.	2	1	1	1	1	2	.
Stachys romana (L.) E.H.L. Krause	+	+	1	1	.	.	.
Catapodium rigidum (L.) C.E. Hubb.	1	1	.	.	+	.	.
Hypochaeris achyrophorus L.	.	.	+	1	.	+	.
Plantago afra L. subsp. afra	.	1	.	.	+	+	.
Trifolium scabrum L.	.	.	2	+		1	.
Crepis neglecta L.	.	.	+	.	.	.	.
Anisantha madritensis (L.) Nevski	.	.	+	.	.	.	.
Coronilla scorpioides (L.) W.D.J. Koch	.	.	+	.	.	.	.
Macrobriza maxima (L.) Tzvelev	.	+	.	.	.	.	.
Plantago bellardii All.	.	+	.	.	.	.	.
Arenaria leptoclados (Rchb.) Guss.	.	.	.	.	.	1	.
Astragalus hamosus L.	.	.	.	.	.	+	.
Festuca myuros L.	.	.	.	.	.	+	.
Hippocrepis biflora Spreng.	.	.	.	.	.	+	.
Polycarpon tetraphyllum subsp. diphyllum (Cav.) O. Bolòs & Font Quer	.	.	.	.	.	+	.
Chenopodietea		.	.	.	.	.	.
Urospermum dalechampii (L.) F.W. Schmidt	+	.	1	1	+	.	.
Anisantha diandra (Roth) Tutin ex Tzvelev	.	.	.	1	.	1	.
Anisantha rigida (Roth) Hyl.	.	.	.	+	.	.	1
Helminthotheca echioides (L.) Holub	.	.	.	+	.	.	1
Knautia integrifolia (L.) Bertol.	.	+	.	.	.	+	.
Allium polyanthum Schult. & Schult.f.	.	.	.	.	.	.	+
Avena fatua L.	.	.	.	+	.	.	.
Bunias erucago L.	.	.	.	+	.	.	.
Festuca danthonii Asch. & Graebn.	.	.	1	.	.	.	.
Lagurus ovatus L. subsp. ovatus	+	.	.	.	.	.	.
Trigonella sulcata (Desf.) Coulot & Rabaute	.	1	.	.	.	.	.
Triticum vagans (Jord. & Fourr.) Greuter	.	+	.	.	.	.	.
Valerianella locusta (L.) Laterr.	.	.	.	.	+	.
Vicia sativa L. subsp. sativa	.	.	.	.	.	.	+
Valerianella rimosa Bastard	.	.	.	.	.	+	.
Euphorbia helioscopia L. subsp. helioscopia	.	.	.	.	.	+	.
Dasypyrum villosum (L.) P. Candargy	.	.	.	+	.	1	.
Dittrichia viscosa & Oloptum miliaceum comm.
Dactylis glomerata L. subsp. glomerata	.	.	.	.	.	.	2
Daucus carota L. subsp. carota	.	.	.	.	.	.	2
Oloptum miliaceum (L.) Röser & H.R. Hamasha	.	.	.	.	.	.	2
Dittrichia viscosa (L.) Greuter subsp. viscosa	.	.	.	.	.	.	2
Amelichloa caudata (Trin.) Arriaga et Barkworth	.	.	.	.	.	.	1
Artemisietea
Silene vulgaris (Moench) Garcke	1	.	1	1	.	.	.
Artemisia vulgaris L.	.	.	.	.	.	.	1
Picris hieracioides L. subsp. hieracioides	.	.	.	.	.	.	1
Sixalix atropurpurea (L.) Greuter & Burdet	.	.	.	+	.	.	.
Verbascum sinuatum L.	.	+	.	.	.	.	.
Convolvulus arvensis L.	.	.	.	.	.	.	1
Festuco-Brometea
Poterium sanguisorba L.	1	2	1	1	1	.	1
Trigonella gladiata M.Bieb.	.	.	+	.	.	.	.
Centaurea deusta Ten.	.	.	+	+	.	.	.
Lygeo-Stipetea	.	.	.	.	.	.	.
Avena barbata Pott ex Link	1	.	2	+	+	1	2
Convolvulus cantabrica L.	2	2	.	1	+	1	.
Reichardia picroides (L.) Roth	.	.	+	.	+	.	.
Bituminaria bituminosa (L.) C.H.Stirt.	.	.	.	.	.	.	1
Molinio-Arrhenatheretea	.	.	.	.	.	.	.
Blackstonia perfoliata (L.) Huds.	+	.	.	.	.	.	.
Elymus repens (L.) Gould subsp. repens	.	.	.	.	.	.	1
Galium mollugo L.	.	.	.	.	.	.	1
Poa pratensis L. subsp. pratensis	.	.	.	.	.	.	2
Rumex crispus L.	.	.	.	.	.	.	+
Trifolium pratense L. subsp. pratense	.	.	.	.	.	.	1
Papaveretea rhoeadis
Papaver dubium L.	.	.	2	1	.	+	.
Lysimachia arvensis (L.) U. Manns & Anderb.	1	.	.	.	.	.	.
Papaver hybridum L.	+	.	.	.	.	.	.
Anthemis arvensis L.	.	.	.	.	.	+	.
Serapias lingua L.	.	.	.	.	+	.	.
Quercetea ilicis & Crataego-Prunetea
Phillyrea latifolia L.	.	+	.	.	.	.	.
Rhamnus alaternus L. subsp. alaternus	.	.	.	.	+	.	.
Pistacia terebinthus L. subsp. terebinthus	.	.	.	+	+	.	.
Rubus ulmifolius Schott	.	.	.	.	.	.	1
Styrax officinalis L.	.	+	.	.	.	.	.
Sambucus ebulus L.	.	.	.	.	.	.	+
Trifolio-Geranietea
Geranium columbinum L.	.	.	.	.	.	+	.
Silene latifolia Poir.	.	.	.	.	.	.	1
Geranium rotundifolium L.	.	.	.	.	.	+	.
Torilis japonica (Houtt.) DC.	.	.	.	.	.	.	1
Ceratodonto purpurei-Polytrichetea piliferi
Cladonia foliacea (Huds.) Willd.	3	2	2	2	2	.	.
Cladonia rangiformis Hoffm.	1	1	2	1	.	.	.
Cladonia furcata subsp. subrangiformis auct. non (Sandst.) Abbayes	.	.	1	1	1	.	.
Psoretea decipientis & Verrucarietea nigrescentis
Didymodon vinealis (Brid.) R.H.Zander	1	3	.	1	2	2	.
Xalocoa ocellata (Fr.) Kraichak, Lücking & Lumbsch	.	.	.	+	.	.	.
Squamarina cartilaginea (With.) P. James var. cartilaginea	.	.	.	1	.	.	.
Psora decipiens (Hedw.) Hoffm.	.	.	.	.	1	.	.
Gyalolechia fulgens (Sw.) Søchting, Frödén & Arup	.	.	.	+	.	.	.
Squamarina stella-petraea Poelt	.	.	.	1	.	.	.
Verrucaria nigrescens Pers. f. nigrescens	.	.	.	2	.	.	.
Hylocomietea splendentis
Pleurochaete squarrosa (Brid.) Limpr.	+	.	+	2	1	.	.

Carex vulpina L.

Sp. Pl. 2: 973 (1753)

New record for Lazio region.

Carex vulpina exhibits a mainly Eurosiberian distribution. It is a recent addition to the Italian flora where it is reported only for Piedmont, Lombardy, Veneto, Umbria and Abruzzo whereas it is considered doubtful in the Aosta Valley. In morphological terms C. vulpina is similar to C. otrubae Podp., but it exhibits stems with sub-winged edges and concave faces; leaves with ligule wider than long (2-5 mm) on the sides protruding beyond the leaf margin; brown glume with green central nerve; dark brown and papillose utricles. The morphological differences between C. otrubae and C. vulpina were identified by Haussknecht (in Österr. Bot. Zeitschr., 1877), and later by Samuelsson (1922). C. vulpina, although, as reported by Smith and Ashton (2006), not all authors agree about the real taxonomic value of all the morphological traits that are considered as diagnostic. In ecological terms, C. vulpina is typical of the banks of the great middle-European and Siberian rivers, adapted to the strong variations of the phreatic level. In the Acque Albule SAC, this species grows within the floodplain of the Aniene river, in the undergrowth and at the edge of Phragmites australis communities bordering the course of the river. In these Phragmito-Magnocaricetea and Molinio-Arrhenatheretea communities C. vulpina is associated with other typical of wet meadows species, such as Carex acutiformis, Ranunculus repens, etc (Table 2 rel.7).

Lolium apenninum (De Not.) Ardenghi & Foggi

Taxon 64 (5): 1039 (2015)

Bas.: Festuca apennina De Not., Repert. Fl. Ligust.: 468 (1844)

Syn.: Lolium pratense subsp. apenninum (De Not.) Banfi, Bracchi & Galasso; Schedonorus apenninus (De Not.) Tzvelev; Schedonorus pratensis (Huds.) P. Beauv. subsp. apenninus (De Not.) H. Scholz & Valdés

New record for Lazio region.

Plant usually of mesophilic and semi-mesophylous mountain meadows, it is widespread in northern and central Italy, up to Campania (southern Italy), and has recently been reported for Sicily (Gianguzzi et al. 2018) while it was currently considered absent in Lazio region. Within the SAC, this species is mainly found on the Molinio-Arrhenatheretea wet meadows (Table 2 rels 1–3) which are mowed during the summer, where meso-hygrophylous species (e.g., Carex otrubae, Cyperus longus) grows together with typical species of mesophilous grasslands (e.g. Poa pratensis, Elymus repens, Agrostis stolonifera). The relatively moist soils allow partial high-coverage of Cirsium arvense, this latter being also advantaged by a moderate degree of anthropic disturbance. The syntaxonomical reference is in the mesophilous fringe of Cynosurion cristati. Lolium apenninum can be also found in Thinopyrum acutum communities developed in small depressions on clayey soils which occupy an intermediate position between Cynosurion cristati and Convolvulo-Agropyrion. At present the Acque Albule SAC represents the lower altitudinal limit for the species in Italy.

Onosma echioides (L.) L. subsp. angustifolia (Lehm.) Peruzzi et N.G.Passal.

Bot. J. Linn. Soc. 157(4): 772 (2008)

Bas.: Onosma angustifolia Lehm.

New record for Lazio region.

Onosma echioides (L.) L. includes 4 subspecies in Italy: subsp. dalmatica (Scheele) Peruzzi et N.G. Passal., from Friuli-Venezia Giulia and Veneto, subsp. canescens (J. Presl et C. Presl) Peruzzi et N.G. Passal., endemic to northern Sicily, subsp. echioides, with a South European range, ranging from Emilia-Romagna to Calabria NW, and subsp. angustifolia (Lehm.) Peruzzi et N.G. Passal. endemic to central and southern Italy (Abruzzo, Basilicata, Puglia and Calabria NE) (Peruzzi and Passalaqua 2004; 2008; Conti et al. 2016). The subsp. angustifolia differs from the other subspecies for the green-ashy leaves covered by very dense greyish-white hairs completely appressed to the leaf blade (Pignatti 2017-2019). In the Acque Albule SAC, O. echioides subsp. angustifolia exhibits its lowermost altitudinal limit for the whole central Italy (41 m a.s.l.). In the study area this species is found within in three different environments, i) fissures of travertine compact pavements dominated by Sedum hispanicum and/or Sedum rupestre assignable to Sedo-Scleranthetea (Tab. 1 rels 3–4); ii) travertine rocky outcrops with other micro-chamaephytes such as Teucrium capitatum and Thymus striatus subsp. acicularis or in mixed hemycryptophytic-therophytic dry grasslands assignable to Ononido-Rosmarinetea and Cisto-Micromerietalia (Tab. 1 rel. 5); iii) dry grasslands together with Ampelodesmos mauritanicus developed on substrates characterized by less rockiness and greater stoniness than the two previous types (Tab. 1 rels 1–2, Fig. 4 ). The syntaxonomic classification of this community remains very uncertain. The high therophytic component, the presence of Petrorhagia saxifraga, Ziziphora acinos, Saxifraga tridactylites and the rich cryptogamic component suggest a classification in the Sedo-Scleranthetea. As a consequence it could still be classified in habitat 6110*. On the other hand the dominance of Ampelodesmos mauritanicus, together with a strong Mediterranean therophitic component could support a classification in Lygeo-Stipetea then a possible identification of the Habitat 5330 “Thermo-Mediterranean and pre-desert scrub” subtype 32.23 - Diss-dominated garrigues.

Ophrys illyrica S. Hertel & K. Hertel.

J. Eur. Orch. 34 (3): 512 (2002)

Syn.: Ophrys araneola subsp. illyrica (S. Hertel & K. Hertel) Kreutz.

FJGJT-J343T-HTJ7

Taxon confirmed for the Lazio region.

Ophrys illirica (Fig. 5) is currently reported for Croatia, Istrian peninsula, southern Dalmatia, Kvarner islands (Devillers and Devillers-Terschuren 2004; Delforge 2016) and southwestern Slovenia (Paušič and Bakan 2016), where it exhibits a scattered distribution. This species belongs to the medium-small flowered group in the O. sphegodes micro-species complex of which O. illyrica represents one of the later flowering species (Hertel and Presser 2006). The presence of O. illyrica was reported in Italy only for the sites of Vetralla and Tarquinia in the northern Lazio region (Antonj et al. 2018) and Abruzzo (Bartolucci & Galasso 2022). This new record of O. illyrica for the SAC Acque Albule (60 m a.s.l.) represents both the southernmost limit of the whole range of the species and the lowermost altitudinal limit in the Italian Peninsula (51 m a.s.l.), the previous record ranging between 185 and 302 m a.s.l. (Antonj et al. 2018). In the study area O. illyrica occurs with few individuals in mixed hemycryptophytic-therophytic semi-mesophilous grasslands (Tab. 1 rel. 6) in areas characterized by rocky outcrops and shallow soils and subjected to a significant degree of anthropic disturbance which leads the community to be characterized by several synanthropic species. For this reason the syntaxonomic classification is intermediate between Stipo-Trachynetea (Brachypodietalia distachyi), Chenopodietea (Brometalia rubenti-tectorum) and Sedo-Scleranthetea.

Typha domingensis (Pers.) Steud.

Nomencl. Bot.: 860 (1824)

Bas: Typha latifolia subsp. domingensis Pers., Syn. Pl. 2: 532 (1807)

New record for Lazio region.

It is a wide pantropical range species. In Italy it is recorded in Lombardy, Veneto, Emilia Romagna, Marche, Abruzzo, Molise, Puglia, Calabria and Sicily. The absence of reports for some regions is probably due to the not easy distinction from the more widespread Typha angustifolia, of which it has long been considered a subspecies and with which it is easily confused. Our specimens exhibit some diagnostic traits which are considered diagnostic for the identification of this taxon (https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=47463), such as the leaf blade gland-dotted adaxially near base, pistillate spike cinnamon to medium brown paler than stigma, ovary separated from the stigma and located close to the base of the pistil. In the Acque Albule SAC, T. domingensis grows near a sulphur water spring in typical helophytic Phragmitetalia communities, together with other Typha species such as Typha angustifolia, T. latifolia, T. laxmannii (see figure 6). Other typical species of wet meadows and marshes occurring in these communities are Phragmites australis, Cyperus longus, C. fuscus, Juncus articulatus, Schoenoplectus tabernaemontani, Ranunculus repens (Tab. 3 rel. 1). The Typha sp. pl. communities are not directly protected by the Annex 1 of the Habitat directive, but in the Acque Albule SAC they represent one of the few survived examples of the helophytic vegetation which in the past was very abundant around the sulphurous pools.

Typha laxmannii Lepech

Nova Acta Acad. Sci. Imp. Petrop. Hist. Acad. 12: 84: (1801)

New record for Lazio region.

Typha laxmannii is a species with a wide distribution ranging from SE-Europe to Japan. In Italy it is reported as native species in all the regions of northern Italy (with the exception of Aosta Valley, where it is absent and Trentino Alto-Adige where it is considered as naturalized alien). It occurs also within the Adriatic side of the Italian Peninsula in Emilia-Romagna, Marche, Abruzzo and Molise regions and in Sicily whereas it is doubtful in Calabria and completely absent in the Tyrrhenian side of the peninsula and in Sardinia. The specimens collected exhibited some diagnostic morphological traits of T. laxmannii that allow it to be distinguished from the co-occurring T. latifolia, such as male and female inflorescence separated by a space wider than 3 cm, a short and large female spike ¼ - ½ shorter than male spike and a relatively low dimension of the mature plants (about 1 m in height). At the same time these specimens cannot be assigned to T. minima Hoppe due to having up to 1 cm wide leaves exceeding the inflorescence. In the study area T. laxmannii was found in the same helophytic community already described in the previous note for T. domingensis.

Vicia pannonica Crantz subsp. pannonica

Stirpium Austriarum Fasciculus (ed. 2) 5: 393. 1769.

New record for Lazio region.

Vicia pannonica Crantz is a species native to central-southern Europe and western Asia (Caucasian region, Turkey and Iran), but was introduced in Europe, U.S.A., North Africa, E-China and the Far East. It is frequently cultivated as a good fodder species and easily tends to become a naturalized species in agricultural habitats, uncultivated or abandoned industrial areas. In Italy there are two subspecies: the subsp. pannonica, rarer and widespread in Lombardy, Veneto, Trentino-Alto Adige, Friuli, Emilia Romagna and Abruzzo that is characterized by yellowish-white flowers, and the subsp. striata (M. Bieb.) Nyman with red-violet flowers, widespread in almost all of Italy, excluding Aosta Valley, Liguria, Campania, Basilicata, Calabria and the major islands. The specimens collected within the SAC exhibited yellow flowers and were found in Thinopyrum acutum meadows and in the contact areas between these latter and the shrublands dominated by Rubus ulmifolius, or the reeds with Arundo donax (Tab. 2 rels 4-6). Despite the absolute dominance of Thinopyrum acutum linked to the clayey soils, these communities are also characterized by several synathropic species and for this reasons their more reasonable classification is in the class Artemisietea than Molinio-Arrhenatheretea.

Zannichellia peltata Bertol.

Fl. Ital. 10: 10 (1854)

Taxon confirmed for Lazio region.

It is a rooting hydrophyte species having an European-Atlantic and W-Mediterranean range. It is known in Italy with certainty only for Emilia-Romagna, Tuscany, Basilicata and Sicily (Bernardo & Caldararo 2014). Zannichellia peltata was described by Bertoloni (1854) on samples from Calabria (“Habui ex fossis, et aquis quietis Calabriae prope Rosarno a Gasparrinio”) but it has not been found since then in that region. Similarly, for Lazio there is only an ancient record relating to a sample collected in Rome (I.IV.1894, leg. “sine coll” and preserved in G (Talavera et al. 1986). Therefore this record for the Acque Albule site is a confirmation of the presence of this plant in Lazio. According to Talavera et al. (1986), the genus Zannichellia is divided into two sections. Sect. Zannichellia includes polyploid species (Z. palustris L., Z. pedunculata Rchb., Z. major Boenn. ex Rchb. and Z. melitensis Brullo, Giusso et Lanf) and is characterized by bearing male and female flowers on the same node and having stamens with short filaments and bilocular anthers. Sect. Monopus Graebner, consisting of Z. peltata Bertol., Z. obtusifolia Talavera, Garcia-Mur. et H. Smit and Z. contorta (Desf.) Chamisso et Schlecht., includes all diploid species and has male and female flowers on different nodes and stamens with long filaments and tetralocular anthers. Our specimens show the latter morphological traits and are distinguished by being annual plants with acute-apex leaves. In the study area this taxon was found in a fresh-water pool at the base of a travertine cliff bordered by a Typha latifolia stand.

Algae (Charophyceae)

The Italian flora includes 39 species of Charophytes, also known as stoneworts (Bazzichelli and Abdelahad 2009; Romanov et al. 2019; Becker 2019; Becker et al. 2021). Their presence often goes unnoticed and few recent studies have analyzed their distribution in Italy (Becker 2019). Stoneworts play an important ecological role in aquatic ecosystems (Vestergaard and Sand-Jensen 2000, Kufel and Kufel 2002), are threatened at European and global level (Baastrup-Spohr et al. 2013; Azzella 2014) and has used in bioindication (Doege et al. 2016; Poikane et al. 2018). In the absence of anthropogenic disturbance, when the ecological conditions are favorable, stoneworts are the dominant elements in a variety of wetland and freshwater or brackish habitats. Stoneworts need freshwater with high conductivity and low concentration of nitrates and phosphates. Therefore, the SAC “Travertini Acque Albule (Bagni di Tivoli)” is potentially a favorable habitat for their proliferation, but few studies report information of stoneworts occurrences. At the beginning of the twentieth century in the “Herbarium romanum” (RO) (Thiers 2022) of the Royal botanical institute were preserved four specimens from the area of Acque Albule: Chara tomentosa, C. gymnophylla, C. crassicaulis, and C. vulgaris (Formiggini 1909). Since then, the botanical studies in this area have mainly focused on the vascular flora while the investigations relating to the Characeae broke off. In the surveys made in the SAC “Travertini Acque Albule (Bagni di Tivoli)”, vegetation dominated by algae of the Charophyceae class was observed in the quarry areas flooded by groundwater. Extensive populations dominated by six species of the genus Chara and one dominated by a species of the genus Tolypella were found.

Tolypella hispanica Nordstedt ex T.F.Allen 1888

This is a particularly rare species, with a range restricted to the coastal areas of the western Mediterranean and at risk of extinction in Italy.

Chara delicatula C.Agardh

Chara globularis Thuillier

Chara aspera Wildenow

Chara vulgaris L.

Chara hispida L.

Chara intermedia A.Braun ex Lange

They are all typical species of oligo-mesotrophic waters rich in dissolved silicates and carbonates. The quarry areas in this context therefore represent an ideal ecosystem for the development of stoneworts (Fig. 10), plants sensitive to increased trophic loads and water turbidity. The first three species belong to the Grovesia Wood 1962 sub-section of the species of the genus Chara with triplostic cauloid and are easy to identify. C. hispida and C. intermedia belong to the Hartmania Wood 1962 sub-section and their identification is more complex, especially, as in our case, when calcareous incrustations on single individuals are found. C. vulgaris, C. globularis and C. delicatula are the most common species. C. globularis and C. delicatula rarely colonize the same water body (Pelechaty et al. 2004) so it is peculiar we have found them growing together in a restricted ecological space such as that of the quarry pools. However the simultaneous occurrence of C. globularis and C. delicatula was already reported for the Lazio region in the volcanic lakes of Bracciano, Bolsena and Vico (Azzella 2014) where, the coexistence of these two species is certainly more plausible given the large size and the high depth gradient of these lakes.

The aquatic community we identified in the Acque Albule area could be classified in the habitat 3140 of 92/43/EEC Directive “Hard oligo-mesotrophic waters with benthic vegetation of Chara spp.”

Figure 4. 

Onosma echioides (L.) L. subsp. angustifolia (Lehm.) Peruzzi et N.G.Passalacqua , together with Ampelodesmos mauritanicus.

Figure 5. 

Ophrys illyrica S. Hertel & K. Hertel.

Figure 6. 

Typha laxmannii Lepech individual (dark and large female spike in the foreground) together with several Typha dominigensis (Pers.) Steud. individuals all around.

Table 2.

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Mesophilous grasslands.<br/>

Relevé nb.	1	2	3	4	5	6	7
Altitude	40	40	40	47	47	47	39
Aspect	,	,	,	,	,	,	.
Slope (°)	,	,	,	,	,	,	,
Rockiness (%)
Stoniness (%)	,	,	,	5	3	2
Area (m2)	25	25	20	25	25	25	30
Cover (%)	100	100	100	100	100	100	100
Carex otrubae & Lolium apenninum comm.
Carex otrubae Podp.	2	2	2	.	.	.	.
Lolium apenninum (De Not.) Ardenghi & Foggi	2	4	2	.	1	+	.
Convolvulus sepium L.	3	2	3	.	.	.	.
Cyperus longus L.	2	1	+	.	.	.	.
Arrhenatheretalia elatioris ; Molinio-Arrhenatheretea
Poa pratensis L. subsp. pratensis	+	2	+	.	1	.	.
Agrostis stolonifera L. subsp. stolonifera	.	2	+	.	.	.	.
Rumex obtusifolius L. subsp. obtusifolius	1	+	+	.	.	.	.
Dactylis glomerata L. subsp. glomerata	.	.	.	1	+	2	.
Daucus carota L. subsp. carota	.	.	.	.	1	.	.
Elymus repens (L.) Gould subsp. repens	.	2	1	.	.	.	.
Tragopogon porrifolius L.	+	.	.	.	.	1	.
Cirsium arvense (L.) Scop.	4	.	.	.	.	.	1
Carex acutiformis Ehrh.	.	.	.	.	.	.	+
Carex vulpina L.	.	.	.	.	.	.	1
Epilobium tetragonum L.	+	.	.	.	.	.	.
Lathyrus pratensis L. subsp. pratensis	1	.	.	.	.	.	.
Lotus tenuis Waldst. & Kit. ex Willd.	+	.	.	.	.	.	.
Potentilla reptans L.	.	.	.	.	.	.	+
Tragopogon pratensis L.	.	1	.	.	.	.	.
Thynopyrum acutum & Convolvulus arvensis comm.							.
Convolvulus arvensis L.	.	.	.	3	3	1	.
Thinopyrum acutum (DC.) Banfi	.	.	.	5	5	4	.
Foeniculum vulgare Mill.	.	.	.	1	2	1	.
Inulo-Agropyrion repentis ; Elytrigio-Dittrichietalia viscosae ; Artemisietea							.
Avena fatua L.	2	2	.	2	1	2	.
Vicia pannonica Crantz subsp. pannonica	.	.	.	2	1	+	.
Silene vulgaris (Moench) Garcke	.	.	.	.	+	1	.
Campanula rapunculus L.	.	.	.	.	+	2	.
Symphyotrichum squamatum (Spreng.) G.L.Nesom.	.	+	+	.	.	.	.
Anisantha sterilis (L.) Nevski	.	.	.	.	.	.	+
Stachys germanica L. subsp. salviifolia (Ten.) Gams	.	.	.	.	+	.	.
Phragmites australis & Urtica dioica comm.							.
Phragmites australis (Cav.) Trin. ex Steud. subsp. australis	.	.	.	.	.	.	5
Urtica dioica L. subsp. dioica	.	.	.	.	.	.	3
Festuco-Brometea							.
Cota tinctoria (L.) J.Gay subsp. tinctoria	.	.	.	.	+	.	.
Festuca rubra L. subsp. rubra	.	.	.	.	+	+	.
Poterium sanguisorba L.	.	.	.	2	.	1	.
Ononis spinosa L. subsp. spinosa	.	.	.	.	.	+	.
Ranunculus bulbosus L.	.	+	.	.	.	.	.
Allium sphaerocephalon L. subsp. sphaerocephalon	.	.	.	.	+	.	.
Chenopodietea & Artemisietea							.
Vicia hybrida L.	.	.	.	3	2	1	.
Dasypyrum villosum (L.) P. Candargy	.	.	.	+	+	1	.
Trigonella esculenta Willd.	.	.	.	.	+	.	.
Trigonella italica (L.) Coulot & Rabaute	.	.	.	.	.	+	.
Allium polyanthum Schult. & Schult.f.	.	.	.	2	+	+	.
Knautia integrifolia (L.) Bertol.	.	.	.	.	.	1	.
Securigera securidaca (L.) Degen & Dörfl.	.	.	.	.	.	1	.
Vicia sativa L. subsp. sativa	.	+	.	.	.	.	.
Galium aparine L.	.	.	.	.	+	.	1
Sherardia arvensis L.	.	.	.	.	+	.	.
Trifolio-Geranietea
Silene latifolia Poir.	.	.	.	.	+	.	.
Geranium columbinum L.	.	.	.	.	+	.	.
Geranium dissectum L.	.	.	.	.	.	.	2
Lygeo-Stipetea & Sedo-Scleranthetea							.
Avena barbata Pott ex Link	.	.	.	1	1	+	.
Bituminaria bituminosa (L.) C.H.Stirt.	.	.	.	2	2	.	.
Quercetea ilicis & Crataego-Prunetea							.
Asparagus acutifolius L.	.	.	.	.	+	.	.
Euonymus europaeus L.	.	.	.	.	.	.	1
Rubus caesius L.	.	.	.	.	.	.	2
Sambucus ebulus L.	.	.	.	.	.	+	.

Table 3.

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Helophytic and hygrophylous communities.<br/>

Relevé nb.	1	2	3
Altitude	44	33	22
Aspect	.	.	.
Slope (°)	.	.	.
Rockiness (%)	.	.	.
Stoniness (%)	.	.	.
Area (m2)	10	4	10
Cover (%)	100	90	100
Typha sp.pl. comm.
Typha angustifolia L.	3	.	1
Typha domingensis (Pers.) Steud	2	.	.
Typha latifolia L.	2	+	.
Typha laxmannii Lepech	1	.	.
Phragmito-Magnocaricetea
Alisma plantago-aquatica L.	.	1	.
Berula erecta (Huds.) Coville	.	.	1
Convolvulus sepium L.	1	.	.
Schoenoplectus tabernaemontani (C.C.Gmel.) Palla	1	.	.
Veronica anagallis-aquatica L. subsp. anagallis-aquatica	.	.	+
Molinio-Arrhenatheretea
Agrostis stolonifera L. subsp. stolonifera	+	+	+
Juncus articulatus L. subsp. articulatus	2	2	1
Scirpoides holoschoenus (L.) Soják	2	2	.
Cyperus longus L.	.	.	+
Elymus repens (L.) Gould subsp. repens	.	.	+
Samolus valerandi L.	.	.	+
Cyperus fuscus L.	1	.	.
Ruppietea maritimae
Zannichellia peltata Bertol	.	2	.
Charetea intermediae
Chara sp. pl.	.	.	5
Tolypella hispanica Nordstedt ex T.F.Allen	.	.	1
Alno-Populetea
Salix alba L.	1	1	.
Populus canescens (Aiton) Sm.	+	.	.
Populus nigra L. subsp. nigra	.	.	+
Papaveretea rhoeadis
Sonchus oleraceus L.	.	.	+
Artemisietea
Symphyotrichum squamatum (Spreng.) G.L.Nesom.	.	+	.
Pegano-Salsoletea
Polypogon monspeliensis (L.) Desf.	.	.	1

Figure 7. 

Diploschistes gypsaceus (Ach.) Zahlbr.

Figure 8. 

Placidium rufescens (Ach.) A. Massal.

Figure 9. 

Squamarina lentigera (Weber) Poelt.

Figure 10. 

Chara aspera Wildenow meadow.

Figure 11. 

The variations of the flooded areas in the quarries of the SAC.

Plant communities, which in their different way of spatial arrangement give rise to the landscape, are living systems whose ecological and structural characteristics are based on a well-defined specific and biogeographical heritage which refer only and exclusively to their lists of plant species. Therefore, the knowledge of the Flora is useful not only to achieve scientific or academic goals but has an essential value for those who deal with environmental management at a political or administrative level. For example, in this research, thanks to the floristic new reports associated with the phytosociological data, the presence of two further Habitats (i.e. 5330 and 3140) listed in the Habitat directive is hypothesized. This information will be considered and verified by the offices that deal with environmental protection (in particular with the application of Habitat Directive rules) and will certainly have repercussions in the future management policies of the SAC. The “Travertini Acque Albule (Bagni di Tivoli)” SAC, considering the environmental uniqueness of the site, could really play the role of identity marker for the local populations. How­ever, this is not happening (at least for the moment). In fact, local populations still perceive the environment that surrounds them as something foreign, sometimes even hostile, towards which no sense of belonging is manifested. It is probable that at the basis of this substantial indifference between local populations and surrounding environment there are the numerous anthropic tampering to which the Acque Albule area is constantly subjected, which has distorted its original characteristics and highly fragmented the landscape. Hence, a greater effort of protection associated to a sustainable management policy based on scientific data is strongly required. It is well-known that the sense of belonging to a place and the willingness to fight for its protection fail when there is no knowledge of it. The restricted list of new floristic records associated to phytosociological relevés published in this paper can be considered a small step forward in that direction.

The new record of Onosma echioides subsp. angustifolia confirms the attitude of the Acque Albule area to host plant species that normally occurs at considerably higher altitudes (e.g. Chaenorhinum rubrifolium and Thymus striatus subsp. acicularis which also occur in this area). In its whole distribution area Onosma echioides subsp. angustifolia is reported for altitudes ranging around 400–700 m (Anzalone et al. 2010; Bartolucci et al. 2018). For this reason, the record at 41 m a.s.l. represents by far the lowermost altitudinal limit in Italy for this subspecies and for the entire group of Onosma echioides s.l as well. From a phytosociological point of view O. echioides subsp. angustifolia is currently reported only for the Stipo austroitaliacae-Seslerietum juncifoliae of the Gargano promontory (Di Pietro and Wagensommer 2008, 2014). Beyond the importance of the new floristic record, it is the peculiar coenological context of O. echioides subsp. angustifolia in the Acque Albule area which is to be considered noteworthy. In fact, this species can be found in three different coenological situations, namely co-dominance with Teucrium capitatum in typical micro-chamaephytic garrigues developed on coarse travertine debris, high frequency species in Sedo-Scleranthetea communities dominated by Sedum hispanicum and co-dominance with Ampelodesmos mauritanicus in open Lygeo-Stipetea steppe-like grasslands on compact travertine slabs.

The new record of Ophrys illyrica represents a very interesting finding, especially considering that this species is even classified as a rare species in its locus classicus area (Pezzetta 2020). In the study this species was found in an intermediate coenological situation between Stipo-Trachynetea (Habitat 6220), Sedo-Scleranthetea (Habitat 6110) and Chenopodietea. A more detailed classification at lower hierarchical rank is not possible at the moment due to the well-known large floristic overlaps between these three classes and to the excessive number of associations currently proposed by the Italian phytosociological literature for Mediterranean therophytic vegetation (see Fanelli and Lucchese 1998; Di Pietro and Blasi 2002; Fanelli et al. 2010; Di Pietro et al. 2021). Our identification of Ophrys illyrica was based on some diagnostic characters of the species, such as the lax inflorescence, the reddish brown, flat to slightly convex labellum with narrow submarginal hairiness and absence of basal hump and also by the late flowering period (see Antonj et al. 2018). We are aware that not all taxonomic doubts are currently resolved in the differentiation and identification of O. illyrica, O. tommasini and O. ausonia. To note, however, that the Acque Albule natural landscape and that of the surrounding hills (e.g. Cornicolani mountains) is typically characterized by “Illyrian” šibljak communities (see Adamovic 1902), in this case dominated by small trees, such as Pistacia terebinthus, Carpinus orientalis, Cercis siliquastrum, and tall shrubs, such as Styrax officinalis, Phillyrea latifolia and Paliurus spina-christi.

The new records of Typha domingensis and T. laxmannii deserve a separate discussion. It should first be established whether their presence is natural or whether instead they were directly or indirectly introduced due to anthropic activities that took place in the proximity of depressed and humid areas. In fact, these two species were found in helophytic communities hosting also T. latifolia and T. angustifolia, that develop in a small overflow loop of a little stream of sulphurous waters bordering a bathhouse and running downstream of an ancient spring pool of sulphurous water (of which it probably represented the natural emissary), now cemented and transformed into a swimming pool. It is known that wetlands are particularly vulnerable for biological invasions especially around newly constructed secondary water bodies or pools. At the same time the genus Typha is composed of highly potential invasive species (Bansal et al. 2019) capable of quickly colonizing mud banks thanks to their high ability of long-distance dispersal and adaptations to strong competition after initial establishment (Shipley et al. 1989). To be noted that Typha species normally build monodominant stands, so that direct interspecific competition within the genus as well as between Typha and other plant species typical of wet areas is not a common phenomenon (Stewart et al., 1997). Rasran et al. (2021) report about different ecological optimum for T. angustifolia, T. latifolia and T. laxmannii as regards their response to different water level with T. angustifolia about 40 cm water depth, T. latifolia 20 cm, and T. laxmannii between 0 and 20 cm up to non-flooded sites. It is possible that the peculiar micro-geomorphology and hydro-geology of the Acque Albule area, characterized by considerable and sudden variations in the water table (also due to the millennial activity of the adjacent travertine quarries and thermal establishments and resorts) and the consequent flooding or drying-up of the wetlands, allowed each of the four cattails species observed to find their own ecological niche. If this were the case, T. domingensis and T. laxmanni would assume the status of native species in the area in issue like T. latifolia and T. angustifolia. These new records are very important from a phytogeographic point of view. Especially for T. laxmanni this would be the first record for the Tyrrhenian side of the Italian peninsula. It should be noted that T. laxmanni is not the only case of species showing this peculiar distribution in the study area. In fact, also Onosma echioides subsp. angustifolia was known to date only from the Adriatic side of the Italian Peninsula and Styrax officinalis itself is an E-Mediterranean species occurring only in the Tyrrhenian side of the Peninsula. On the other hand, the fact that T. laxmannii and T. domingensis had never been recorded previously in the study area and that the wetlands in which we collected them is placed in spatial contact with a thermal resort may leave doubts on a possible recent arrival of these species linked to the remodeling work carried out in the last two decades on the ancient natural pools to transform them into swimming pools. Further studies will be needed to decide on the native status of both T. domingensis and T. laxmanni. However, the constant tampering of the natural areas (especially the humid ones) in the Acque Albule site still remains a major problem for the monitoring of ecosystems and the conservation of biodiversity. Already the summer following our spring field surveys, the helophytic community dominated by Typha species was inexplicably subjected to mowing in defiance of all the rules and prohibitions relating to the conservation measures that characterize a protected area.

As far as the bryophytic flora is concerned, the new regional record of Grimmia montana is a further example of a species which is normally found at higher altitudes and that marks in the Acque Albule site one of its lowermost stations in peninsular Italy.

Considering the valuable lichen flora, Squamarina lentigera stands out because it is of particular interest both from a phytogeographic and conservation point of view. It belongs, together with Gyalolechia fulgens, to a small group of sub-continental species present in areas with a dry-sub-continental climate (e.g. dry alpine valleys, parts of Mediterranean Italy) which represent less than 4% of the total Italian lichen flora (see Nimis and Martellos 2022). It is only locally common, especially on gypsaceous or clayey soil in dry grasslands and declining rapidly.

Finally, of particular interest is the reporting of stonewort pools. The surveyed communities can be classified in the Charetea intermediae class belonging to the habitat of community interest “3140 - Calcareous oligo-mesotrophic waters with benthic vegetation of Chara spp” which had never been reported for this SAC. It should be emphasized however that the reference to the Habitat 3140 is just to be considered a preliminary hypothesis. In fact, quarries are typical “not natural” environments that are strongly shaped and reworked by the travertine extraction activity so that the newly formed communities dominated by stoneworts identified in the study area are not currently part of the natural landscape of the SAC. However, part of the innovative character of the Habitats Directive is precisely that of protecting some habitats whose biotic characteristics are clearly the result of human action (e.g. 6210*secondary grasslands, 6310 Dehesas with sclerophyllous trees, or, even more fitting, the 6130 Calaminarian grasslands on old terrils or spoil heaps around mines). For this reason, even the pools with stoneworts identified in the study area, although temporary and strongly subject to travertine management and exploitation, could be included in a sustainable management project aimed at safeguarding biodiversity directly inside the quarry. There are already virtuous examples of protection of new born ecosystems in Europe and they expressly concern quarry environments. For example, LIFE14 NAT/BE/000364 "life in Quarries" project has succeeded with concrete actions in protecting newly formed ecosystems referable to Habitat 3140. Based on these positive examples, we could work on a special type of in situ conservation, identifying protection areas directly in the quarries where the degree of naturalness is notoriously very low, but when present, it can play a key role in the conservation of ecosystems which, as is the case of SAC “Travertini Acque Albule (Bagni di Tivoli), are no longer traceable in natural areas. On the basis of a diachronic analysis using satellite images, the flooded areas inside the quarry exhibit a relatively short life and changed their spatial position in relation with the processes necessary for the extraction of the travertine (Fig. 11). The detected communities could therefore be considered pioneer communities although the occurrence of species (e.g. Chara hispida and Tolypella hispanica) that generally dominate in stable communities. In the flooded quarry areas the waters are oligotrophic in a first stage (Seelen et al. 2021) and this promotes the colonization by Charetea intermediae species (Habitat 3140). If the hydrological regime allows the maintenance of good water quality and low nutrients concentration, Habitat 3140 stabilizes. Otherwise, a process of natural eutrophication occurs due to water stagnation. The increase in the load of nutrients leads to a regime-shift towards eutrophic conditions (Viaroli et al. 2002) and stoneworts decreasing.

The authors thank Professors Simonetta Bagella, Marta Puglisi and the anonymous reviewer for their constructive comments and suggestions to the manuscript. The authors thank also the members of Protezione Civile of the Tivoli Municipality and the Rangers of the Monti Lucretili Regional Park Authority for their logistic support during the sampling work. The study was financed by Ente Parco Naturale Regionale dei Monti Lucretili (det. Dir. n. 76 del 02/04/2021): Agreement between Ente Parco Naturale Regionale dei Monti Lucretili and Department PDTA of Sapienza Università di Roma (Resp. Romeo Di Pietro). The work of M.M. Azzella concerns a research project partially funded by the Italian legislative decree 1062/2021.