$¢PhytoKeys PhytoKeys 251: 143-159 (2025) DOI: 10.3897/phytokeys.251.129982 Research Article Sideritis carpetana (Labiatae), a new high-mountain Mediterranean species from the marble outcrops of the Sierra de Guadarrama (Central System, Madrid, Segovia, Spain) Jose Luis Izquierdo’, Rosina Magafia Ugarte™®, Alba Gutiérrez-Girdn2®, Concepcidn Obdn de Castro™®, Diego Rivera Nufiez*®, Rosario G. Gavilan?® ee wo NY — Research and Management Centre of Sierra de Guadarrama National Park, E-28740 Rascafria, Spain Botany Unit, Pharmacy Building, University Complutense of Madrid, E-28040 Madrid, Spain Plant Biology Department, University Miguel Hernandez of Elche, Avenida de la Universidad s/n, E-03202 Elche, Spain Plant Biology Department, University of Murcia, Campus de Espinardo, Edificio n° 20, E-30100 Murcia, Spain Corresponding author: Rosario G. Gavildn (rgavilan@ucm.es) OPEN Qaceess Academic editor: Alan Paton Received: 18 June 2024 Accepted: 13 November 2024 Published: 17 January 2025 Citation: Izquierdo JL, Magana Ugarte R, Gutiérrez-Giron A, Obon de Castro C, Rivera Nufez D, Gavilan RG (2025) Sideritis carpetana (Labiatae), a new high-mountain Mediterranean species from the marble outcrops of the Sierra de Guadarrama (Central System, Madrid, Segovia, Spain). PhytoKeys 251: 143-159. https://doi. org/10.3897/phytokeys.251.129982 Copyright: © Jose Luis Izquierdo et al. This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International - CC BY 4.0). Abstract Anewspecies of Sideritis (Sideritis carpetana) is described from the calcareous, high-moun- tain Spanish flora in the central part of the Iberian Peninsula. It is found in a Mediterranean climate at high-elevation, perennial, calcareous grasslands, as well as in marble screes of anthropogenic origin in the Sierra de Guadarrama, Central System (Spain), in a reserve area within the Sierra de Guadarrama National Park, at 1996 m asl. Taxonomic morpholog- ical measurements were performed on collected specimens from Sierra de Guadarrama as well as on geographically-adjacent Sideritis (i.e., S. glacialis, S. pungens, S. hyssopifolia). The relationships among them were then explored with multivariate analysis. Sideritis car- petana is a dwarf shrub with an erect or decumbent habit, growing up to 15 cm; non-woody twigs with long hairs of 3-4 cells, leaves are entire, linear-oblanceolate, sparsely covered with trichomes; inflorescence is spiciform or slightly verticillated, flowers are yellow and nutlets ovoid. A key is supplied to help distinguish it from other high-mountain Iberian species included in section Sideritis. The species is unique in its combination of morpho- logical and autoecological characters. S. carpetana shares similarities with S. glacialis, a species from Sierra Nevada, and its northern Mediterranean variant, S. glacialis subsp. fontqueriana from Sierra de Gudar. They share morphological characters that are absent in other high-mountain Sideritis, reinforcing their Mediterranean character, as opposed to a more temperate or submediterranean character, such as those of the hyssopifolia group. Key words: Calcareous high-mountain grasslands, Carpetan Mountains, high mountain species, marble outcrops, Mediterranean area, Sideritis sect. Sideritis, Sideritis subsect. Fruticulosa Introduction The genus Sideritis L. contains 140 species found across Eurasia (Russia, Tibet, and western China), with an important centre of diversity in the Iberian Peninsula and Macaronesia. Regarding the Iberian Peninsula, there are 35 species consid- ered in Section Sideritis, and 24 in Macaronesia included in Subgenus Marrubi- 143 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species astrum (Pérez de Paz and Negrin 1990; Las Heras et al. 1999; Rios et al. 2001; Morales 2016). The number of taxa increases to 100 in one of the most compre- hensive works for the genus (Ob6n and Rivera 1994). Sideritis is an interesting genus with a large number of endemics and significant variability in morpholog- ical features; but it is further complicated by the hybridization process, which occurs even between species from different sections that coincide in the same area. This variability is also associated with its broad habitat affinity on siliceous or calcareous substrate at all altitudinal levels, while consistently demonstrating a strong heliophilous character (Socorro 1982; Peris et al. 1990; Morales 2016). On the La Flecha Pass, which connects the provinces of Madrid and Segovia, at an elevation of around 2000 m asl., we discovered a few small populations of Sideritis during our fieldwork in the calcareous uplands of Sierra de Guadarra- ma National Park that, initially appeared to be members of the Sideritis hyssopi- folia group. An in-depth study of the plant revealed similarities with S. glacialis, whose closest populations are found in Sierra de Gudar (Teruel province; ca. 400 km away). Extensive examinations led us to identify Sideritis carpetana as a new species in the Iberian flora, presented in this article. Materials and methods Study area and vegetation The Central System is a mountain range running northeast-southwestern in the centre of the Iberian Peninsula. It reaches its maximum altitude at 2592 m asl in Sierra de Gredos (Almanzor peak). It divides the “Meseta”, a broad, elevated plateau with an average elevation of 670 m asl, surrounded by other mountains like Montes de Leén (NW) and the Cantabrian Range (N), which together define the boundary between the Temperate and Mediterranean regions. The Sistema Central comprises the following mountain ranges, from east to west: Sierra de Ayllon, Sierra de Guadarrama, Sierra de Gredos, Sierra de Gata, Pena de Francia and Sierra de Estrela. This new species (Sideritis carpetana) was found in the calcareous peaks of Si- erra de Guadarrama. The calcareous outcrops of Sierra de Guadarrama are locat- ed in “Collado de la Flecha” (La Flecha Pass) and the head of Artifiuelo creek, with- in the Sierra de Guadarrama National Park. This area is shared by the provinces of Madrid and Segovia, encompassing the two towns of Rascafria in Madrid (Moun- tain Public Land n. 153 “Las Calderuelas y otros”) and Trescasas in Segovia (Moun- tain Public Land n. 257 “La umbria de los Saltillos”). Dolomitic marble outcrops are the predominant feature among the glandular orthogneisses in these mountains. Their distribution is scattered and covers a surface of ca. 120 ha and at an altitude of ranging from 1700 to 2000 m asl (Fig. 1). Prior studies have demonstrated the fascination with this area of the Sierra de Guadarrama, which acts as a genuine “floristic island” amidst the distinctive silicicolous carpetan communities of the Central System. Although there are some notable distinctions, there is also a clear relationship with the closest high mountain limestones, the Gudar and Javalambre mountains (Southern Iberian System; Pérez Badia et al. 1998; Gavilan et al. 2012). Floristically, there is a set of taxa found exclusively in this locality within the Sistema Central, such as Astragalus nevadensis subsp. muticus, that grows along with another group of plants that also grow in the foothills of Sierra de PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 144 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species Figure 1. Geographical location of the study region in Spain, between the provinces of Segovia and Madrid. The marble crop status (blue square) is shown on the map. All of these mountains with summits above 1500 m asl are included in the Sierra de Guadarrama National Park. Guadarrama (Segovia province) or in the Sierra de Pela (eastern part of Central System), such as Arenaria erinacea, Seseli montanum, Iberis saxatilis, Teucrium expassum or Astragalus incanus subsp. nummularioides. Vegetation is formed by basophilous rocky communities (found in rocky outcrops) interspersed with dry grasslands rich in chamaephytes, dominated by basophilous species with the presence of acidophilous elements. Morphological study Morphological characters, measurements and detailed descriptions were con- ducted following the outlined by Rivera and Obdn (1990), Ob6n and Rivera (1994), Rivera et al. (1999), using both fresh materials and dried specimens (preserved herbarium specimens). We have studied high-mountain relatives of Sideritis close to our study area to check morphological similarities and differences. The closest areas appear in Sierra de Gudar and Sierra de Javalambre. We added the PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 145 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species Cantabrian Range as the farthest because of the Mediterranean component of its flora that relates it to the others. We did not consider the Pyrenees with a tem- perate climate, areas more distant the Cantabrian Range nor the Sierra Nevada, a Mediterranean mountain sharing high mountain Sideritis species with Sierra de Gudar (Morales 2016). Populations from Sierra de Guadarrama were compared with specimens of high-mountain Sideritis species: from S. de Gudar and S. de Javalambre, S. glacialis (S. glacialis subsp. fontqueriana Ob6n and Rivera; S. fer- nadez-casasii Rosello et al), S. pungens (S. pungens subsp. javalambrensis) and Sideritis hyssopifolia (Table 1). Due to the morphological variability in the complex of S. hyssopifolia, a comparison was made with the nearest subspecies in terms of distance and altitude, i.e., S. hyssopifolia subsp. nocedoi Ob6n and Rivera from the Cantabrian Range (Table 1). The accepted systematic arrangement of Sideri- tis follows Flora iberica (Morales 2016), but takes into account the variability re- ported in Obdn and Rivera (1994). Additional relevant sources studied include Pau (1887); Rivas Goday and Borja (1961); Mateo and Lopez Udias (2000); Mateo and Pisco Garcia (2000); Peris et al. (1994); Rosello et al. (1994) and Rosell6 et al. (2000). Plant names follow Brummitt and Powell (1992). Acronyms of herbaria are as indicated in Index Herbariorum and its supplement (Holmgren et al. 1990; Holmgren and Holmgren 1993; Thiers (updated continuously)). A key is provided to distinguish all Sideritis that can reach high elevations in the Iberian mountains. Statistical analysis We conducted an exploratory analysis to understand the relationships between this new species and the other high-mountain Iberian Sideritis species. The pro- cess was performed in two stages. The first stage consisted of examining all Sideritis species present in the Iberian Peninsula at medium to high altitudes that share similarities in morphological characters (Suppl. material1: table S1). Next, we compared the suspected new species to geographically-close taxa. During the first phase, we differentiated material from Sierra de Gudar and Javalambre (both for S. glacialis subsp. fontqueriana and S. javalambrensis) into two forms based on altitude range: Form 1 for specimens from the highest altitude, and Form 2 for those from lower altitudes (see Fig. 2). Doing so allowed for more accurate definitions on the altitudinal criteria of the species under study. We performed an agglomerative clustering method by means of Weighted Neighbor Joining, us- ing the Sokal-Sneath index of dissimilarity (un2) supported by 500 bootstraps for 89 morphological variables of high-mountain Iberian Sideritis (Rivera et al. 2014; Rohrs et al. 2023). In the second stage, we conducted an ordination method us- ing Factor Analysis, a model of the measurement of a latent variable that cannot be directly measured with a single variable. This is a reduction technique that cap- tures the variance in a small set of variables (Howard 2016; Tavakol and Wetzel 2020). We implemented the same dissimilarity index as in the clustering analysis. Results The multivariate analysis results indicated that this species is sufficiently inde- pendent from the rest of Sideritis dataset (Fig. 2a, b). The dendrogram of the hierarchical clustering (Fig. 2a) displays three main groups. The first group of the dendrogram (1, Fig. 2a) includes S. hyssopifolia subsp. nocedoi from the PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 146 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species Table 1. Comparison of Sideritis carpetana sp. nov. with other closely-related taxa. Data on S. glacialis, S. pungens and S. hyssopifolia from Obon and Rivera 1994; Rivera et al. 1999; Rosell6 et al. 2000; Rios et al. 2001; Morales 2016 and studied specimens. (See Suppl. material 1). Characters Growth Height (cm) Non-woody branches Arrangement of hairs Length of hairs (um) N. cells of trichomes Trichome cell type Apical trichome cell type Lower leaves Length (mm) Width (mm) Shape Type of apex Length of trichomes (um) Inflorescence Length (cm) Number of verticillasters Lower verticillaster Direction of bracts bract shape bract length (mm) bract width (mm) Number teeth of semibracts Abaxial Surface of bracts Gland density Trichome density Trichome length (um) Apical cell trichome type Calyx Length in blooming (mm) Length teeth Corolla length (mm) Sideritis carpetana sp. nov. decumbent to erect 10.9-14.7 holotrichous 700-1280 3-4 cylindrical band-shaped 8-12.5 vdeo ets Be) linear-oblanceolate to oblanceolate acute to apiculate 700-1260 258 5-6 erect-patent to patent ovate or trullate 6.5-9 43-75 7-10 very scarce scarce to abundant 800-1300 cylindrical /band shaped 6-8.3 2.5-3;5 8-10 S. glacialis (Sierra de Gudar) = S. glacialis subsp. fontqueriana = S. fernandez-casasii procumbent up to 25 holotrichous 1000-1500 Aare) band-shaped band-shaped 4-9 1=2 linear-spatulate acute 800-1200 1553 1-7 (8) erect-patent trullate 5-7/7 6=7 9-10 (14) absent abundant 800-1200 conical 5-6 (8) 1.5-2.5 8-10 S. pungens (Sierra de Javalambre) = S. pungens subsp. javalambrensis erect up to 22 goniotrichous to holotrichous 500-1300 2e3 cylindrical conical 10-28 2-4 linear to oblanceolate apiculate 700-1000 LG (1)4-6 patent ovate 8-12 VO>1:2 14-16 scarce to very scarce scarce to very scarce 800-1200 conical 79 Sideritis hyssopifolia subsp. nocedoi (Cantabrian Range) procumbent to erect up to 45 goniotrichous to holotrichous 700-1000 223 cylindrical conical pals 2-4 lanceolate-spatulate obtuse 200-900 erect-patent ovate or trullate 5-8 4-6 0-3 absent scarce to very scarce 200-800 conical a=? Cantabrian Range (Shn; Fig. 2a) and S. tugiensis from southeastern mountains of the Iberian Peninsula, Sierra de Segura (St; Fig. 2a). The second group (2, Fig. 2a) includes the new Sideritis from Sierra de Guadarrama (Sc; Fig. 2a) and a group of species included in S. glacialis. The specimens from the summits of Sierra Nevada, in the south of the Iberian Peninsula (S. glacialis subsp. gla- cialis, Sgg; Fig. 2a), and the two forms from Sierra de Gudar in central eastern Spain (S. glacialis subsp. fontqueriana, Sgf1, Sgf2; Fig. 2a), which show strong similarity, suggesting they could be treated as belonging to the same subsec- tion. A third group (3, Fig. 2a) consists of two smaller subgroups. One sub- group is from Sierra Nevada and related to S. glacialis but from lower altitudes PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 147 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species a ~ [2] [3] 0.9 0.56 v8 0.38 0.71 0.95 0.92 at Shn Sef, Sef, Ses Sc Shi Siz Sbr Sgv Sgve b Factor Analysis (Axes 1, 2) 4 e Sideritis carpetana Sideritis javalambrensis e Sideritis glacialis 2 Sideritis hyssopifolia subsp. fontqueriana subsp. nocedoi - e -3 Figure 2. a hierarchical clustering (Weighed Neibor Joining) of the Iberian high-mountain Sideritis. The new species Sideritis carpetana is situated in cluster 2 with Sideritis glacialis gr. (Sc, S. carpetana sp. nov, Sgf, S. glacialis subsp. fontqueriana with two forms 1 for high-mountain areas and 2 for middle areas, Sgg, S. glacialis subsp. glacialis) b ordi- nation diagram (Factorial analysis) of Sideritis carpetana and close taxa (Axes 1 and 2). S. carpetana is situated close to Sideritis glacialis subsp. fontqueriana along axis 1 but far from the other two. Axis 2 also shows the independence of S. carpetana from the other three species. PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 148 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species (oromediterranean belt) and ascribed to S. glacialis subsp. vestita (Sgve; Fig. 2a) and S. glacialis subsp. virens (Sgv; Fig. 2a). The second subgroup compris- es those Sideritis species found in Sierra de Javalambre in the central eastern part of the Iberian Peninsula (S. pungens or S. javalambrensis, Sj1, Sj2; Fig. 2a). Factor analysis ordination showed the separation of the new Sideritis species from closely related ones along axis 1 and axis 2 (Fig. 2b). The first factor anal- ysis axis shows how Guadarrama Sideritis and S. glacialis from Sierra de Gudar (S. g. fontqueriana) are separated in the negative part; while S. h. nocedoi from Cantabrian Range and S. javalambrensis (= S. pungens) from Sierra de Java- lambre are separated in the positive part. The second axis clearly distinguishes the Guadarrama Sideritis from S. javalambrensis in the most positive part of the axis, which is also in the positive part but closer to 0; and separates S. glacialis from Sierra de Gudar and S. nocedoi from Cantabrian Range in the negative part. The results from the multivariate analyses clearly recognize the indepen- dence of this new Sideritis species from Sierra de Guadarrama. Additionally, the morphological analyses results (Table 1, Appendix 1) led to the identification of a new species from the summits of Sierra de Guadarrama that we are going to call Sideritis carpetana Izquierdo & Gavilan, sp. nov.; that is to be included under Sect. Sideritis, subsect. Fruticulosa due to its relationships with Sideritis glacialis subsp. fontqueriana from Sierra de Gudar, as shown in Fig. 2a, b. The following text presents the diagnosis, holotype and other characteristics of this new species, including phenology, distribution, habitat and the detailed descrip- tion with all morphological characters studied. Sideritis carpetana Izquierdo & Gavilan, sp. nov urn:lsid:ipni.org:names:77355303-1 Description (Figs 2-5). Dwarf shrub with erect or decumbent habit, growing up to 25 cm. Stems are holotrichous with white hairs. Branchlets at the base have cy- lindric trichomes of 3-4 cells, except the apical band-shaped being 0.7-1.3 mm long. Leaves are entire, linear-oblanceolate, measuring 8-12.5 x 2.5-3.5 mm long, markedly trinerved and mucronated, sparsely covered by trichomes on the upper side of leaf and more densely covered on the underside. Middle bracts measure 6-8 mm. The inflorescence is spiciform or slightly verticillated with 5-6 whorls, each enclosing 5(6) flowers. The calyx is campanulate, densely haired, 6-8.3 mm long, teeth spiny-acuminate, equal, and erect, 2.5-3.5 long, with continuous carpostegium, spines 1-1.5 mm. The corolla is yellow 8—9 (10) mm, with entire or two slight lobes in the upper lip and three in the lower lip, the central bigger than the other two; stamens included in the corolla tube, with filaments 4—5 mm long; style 3-3.5 mm long; ovoid nutlets 1 mm (see Suppl. material1: table S1 for diagnostic features and detailed description). This species lives in the mountains of Sierra de Guadarrama, in the marble outcrop reserve of La Flecha Pass, in the Sierra de Guadarrama National Park, on Mediterranean high-mountain calcareous grasslands and screes of anthro- pogenic origin, mainly in southern exposures, at an altitude of 1990-2000 m asl. Holotype. * Holotype: SPAIN, Madrid: Sierra de Guadarrama. Collado de la Flecha, 1996 m asl. 14/07/2021. 40.928276, -3.925597 (ETRS89), Rosario G. Gavilan and José Luis Izquierdo, MAF [MAF 181439]. PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 149 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species = 4 - A is wi RS Y" ys! tie SAE RSE A | WES fo Nt (es r, ee Waa Mao ad = 5 fee wri ‘i 4 AMIE ANA ae ‘ a i j iid KAT A ih SE AC. Sey fe NANA Joi (Fo AN : i SN at Ww . A : OY , ia NAGAI ae Pei Ve d Wie . PPO ee ee = a Aa a ‘a — LEG NMiW GPA: (WO Fak i lee — EY iy el f? pa eo ae aa eee ee gene ee : fas a = ee ie fe a er at Figure 3. Sideritis carpetana, Sierra de Guadarrama, La Flecha Pass (1996 m asl) a habit b, c leaves d, inflorescence detail e verticillaster f, g bracts, lower face (f) upper face (g) h, i, j flower, front and lateral view k, | corolla detail showing the in- ner part with stamens (k) and outer part (I) m, n open calyx with ginoecious (m) and teeth detail (n). Drawing by J. Pizarro. PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 150 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species * eS te Ay na 3 é, ! lad y P . : SS : ivf i Fi. ae me i —— ne Figure 4. Sideritis carpetana, Sierra de Guadarrama, La Flecha Pass (1996 m asl) a habit b Lower branches c inflores- cence detail showing lower verticillaster bract and calyx d inflorescence detail showing upper verticillaster bract. Phenology. The species is known to have its prime flowering season from June to July; and it is reported to fruit from August to October. Distribution and habitat. Sideritis carpetana grows in Mediterranean high-mountain calcareous grasslands of Festuco-Ononidetea striatae (Festuco carpetanae-Astragaletum mutici) and in marble screes of anthropogenic origin at La Flecha Pass, Sierra de Guadarrama, at an altitude of 1996 m asl (Table 2). The geographical distribution is restricted to the marble outcrop reserve within the Sierra de Guadarrama National Park. In these territories, winter snow cover lasts for approximately five months, while summer rainfall is scarce as is typi- cal of a Mediterranean territory. PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 151 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species Table 2. Phytosociological relevés recorded in La Flecha Pass, Association Festuco carpetanae-Astragaletum mutici Gavilan, Diez-Monsalve, Izquierdo, Gutiérrez- Giron, Fernandez-Gonzalez & Sanchez-Mata (Sideritido-Arenarion, Festuco hystricis-Poetalia ligulatae, Festuco histricis-Ononidetea striatae). Species Indices and phytosociological association typology (vegetation type) follow J. Braun-Blanquet (1928). Altitude 1996 | 2000 | 1995 1995 | 1990 | 1995 | 1990 | 1995 Area 4 1 2 1 1.5 1.5 1 2 Exposure (°) 182 350 160 176 203 189 117 150 Plot number 1 2 3 4 5 6 7 8 Festuco-Ononidetea characteristics Sideritis carpetana 4 3 Poa ligulata 1 1 Astragalus nevadensis subsp. muticus 3 +) 32/3/N o_ a Oe) N Seseli montanum f 1 NN} +) 4] +4) 0 Iberis saxatilis 2 : ; + Arenaria erinacea : L : : + Bupleurum ranunculoides 1 Veronica javalambrensis it Festucetea indigestae differentials Festuca curvifolia 1 Leucanthemopsis pallida Thymus praecox +/+4/)4/% —_ —_ — —_ Jurinea humilis Dianthus pungens subsp. brachyanthus : : . + Other species Arenaria obtusiflora subsp. ciliaris + Centaurea triumphetii Cynosurus echinatus Coronilla minima subsp. minima +)t]) 4) a] 4+ + + Festuca iberica Agrostis castellana + + Allium sphaerocephalon : : + + Carduus carpetanus + ; 1 Bromus tectorum . ’ : ; d i . + Acinos alpinos ; 4 : ? , + Ceterach officinarum Cetraria aculeata : + Galium idubedae Chaenorrhinum segoviense 1 Herniaria cinerea ‘ 1 Holcus gayanus + : p + + + + + Hornungia petraea Lactuca viminea é : : k : + Nardus stricta : 1 Poa bulbosa ! : . ? ‘ + + + Rumex angiocarpus + Saxifraga granulata Sedum album + 1 ; + 1 1 + + Silene legionensis + ; 1 . : + Teesdalia nudicaulis : : + Thlaspi stenopterum . ; A : + : + + Viola riviniana : . ’ 2 1 Etymology. The specific epithet ‘carpetana’ refers to the former inhabitants of these mountains that were called ‘carpetanos’ (carpetan, in English). Moreover, “Cordillera Carpetana”, or Carpetan Range, is a synonym for Sistema Central (Central System), the mountain range that divides the northern and southern pla- PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 152 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species , er s " ans es 2 “ x. ick Figure 5. Sideritis carpetana natural habit in the marble anthropogenic outcrops of La Flecha Pass (Sierra de Guadarrama National Park). teau in central Iberian Peninsula. The Sistema Central comprises several moun- tain ranges: Sierra de Estrela, Sierra de Gata, Pena de Francia, Sierra de Gredos, Sierra de Guadarrama and Sierra de Ayllén from western to eastern territories. Key to the Iberian high mountain Sideritis (> 1996 m asl) 1 Plant with some petiolated leaves .................... S. lurida J. Gay ex Lacaita ee CAVES WITOLD SUNT it tut cr Pr neh itltl sana ll dill at eapraeel URES toes Poa dill abl tas 2 2 Leaves linear or lanceolate, ENtireS................cccscccessecceesseceeesseeeesseeeessseeeees 3 - Leaves lanceolate, elliptic, ovate u obovate, toothy o lobed...................... 4 9) KINMORES CENCE INS ICI sa) eee ae Jee ne ee erase dt S. carbonellii Socorro = WTIMMOLESCEMNE Ske ZFC Miley, sense cee mers legend seme es 50 95, ene ee ys oles wero a oe 5 A. ‘Feavesiless thar sii WiGe wt ...Me.....0. 29 aan R eo WE ee alton 6 =, gheavessDiggenthiaticst MMW AG aegesass ooo lores nes Perl era nan 22ers errs omen 7 B71 SBRACTS Os eno oP RAN, meet cahere nc rari a teuiadh daa heer emeebaceat S. incana L. = ABTACTSsesO SMITA sae hass tA meeemennes, arerrnmmes contin tm memaumey ons, 208, S. pungens Benth. 6 ‘Hairs-ofithe:shootbase:short((<: lpn). nge Bn ee tee 8 =. sHdirsofthe shoot base Omg Sil (arn) rcs arene eri oe eee 9 7” | Wentrcillatedrinhlores CemGery Sx rts 2s ero ee ore see S. hirsuta L. - Spiciform or slightly verticillate infloreSCeNCe ..............ccccccesscceessseceesseeeeeees 9 8 Trichomes of base branchlets goniotrichous to holotrichous, with 1-3 Cells thietapiCal (COMIC. oo. wtnts ten eenee ener ee crake S. gr. hyssopifolia L. - Trichomes of base branchlets holotrichous, with 3-4 cells, the apical- DanidaShabed 10.200 eg EMail Re, Me aul un 9 9 Hairs of the shoot base 1-2.5 MM..............cccceeseeeees S. gr. glacialis Boiss. - Hairs of the shoot base 0.7-1.3 MM...............0006 S. carpetana spec. nov. PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 153 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species Discussion Plants living on the marble outcrops of Sierra de Guadarrama enrich the prev- alent silicicolous flora of the area. The majority of these calcareous plants are found in foothill areas, but a small number of them reach altitudes above the timberline (1800-2000 m asl) and are thus included in the Sierra de Guadar- rama National Park reserve. These outcrops have been identified as a floris- tic island surrounded by the characteristic glandular orthogneisses of these mountains (Pérez Badia et al. 1998; Gavilan et al. 2012). According to Ob6n and Rivera (1994) and Rivera et al. (1999), Section Sideri- tis, subsection Fruticulosae includes Sideritis with long hairs covering the base of the branchlets (Obon and Rivera 1994); it is also holotrichous, formed by cylin- drical cells, except the apical band-shaped (forming bands along the cell). This subsection consists of five species (S. fruticulosa, S. spinulosa, S. subspinosa, S. jahandiezii and S. glacialis), but the only species growing at high altitudes in the cryoromediterranean belt are those of the S. glacialis complex (subsp. gla- cialis and subsp. fontqueriana) or oromediterranean (subsp. vestita and subsp. virens). These species inhabit the south of the Iberian Peninsula (Sierra Nevada and surroundings mountains), with the exception of subsp. fontqueriana, which grows at the Sierra de Gudar which is close to Sierra de Guadarrama, and whose specimens have been studied in the comparison with Sideritis carpetana. Sideritis belonging to subsection Hyssopifoliae have shorter hairs at the base of the branchlets, goniotrichous to holotrichous, formed by cylindrical cells, and the apical cell is conical. This subsection includes 7 species (S. brachycalix, S. get- ula, S. hyssopifolia, S. pungens, S. maura, S. carbonellii and S. ochroleuca; Obon and Rivera 1994). The species found in high mountain areas are S. carbonellii, S. pungens and S. hyssopifolia. We have compared with Sideritis carpetana those found in locations close to Sierra de Guadarrama and on calcareous substrate: i.e., S. pungens (subsp. javalambrensis, Sierra de Javalambre) and S. hyssopifolia (subsp. nocedoi, Cantabrian Range). After comparing the studied characters of all the selected species in both subsections (see Table 1), we included S. carpet- ana in subsection Fruticulosae. This is due to the fact that it has long hairs at the base of the branchlets, which are formed by 3-4 cells (including the apical, that is band-shaped) while in the others these are conical. Like all species in this sub- section, hairs in the inflorescence axis or bracts are similar to those at the base of branchlets. Morphological findings have been validated by multivariate analyses. Similarity in macromorphological characters with other orophilous Sideritis, such as hair length and the type of leaves, demonstrates the ecological con- vergence of these species due to the harsh environmental conditions in high mountain areas and the intense speciation process (Rios et al. 2001). This is the case for the S. glacialis complex, which includes four mountainous taxa, and S. hyssopifolia, with two subspecies with an orophilous distribution, subsp. nocedoi from the Cantabrian Range and subsp. eynensis from eastern Pyre- nees. Although Sierra de Guadarrama is sometimes thought of as submedi- terranean due to a slightly shorter summer arid season compared to southern territories like Sierra Nevada, it shares similarities in ecology, distribution, and characters with the Sierra de Gudar Sideritis (S. glacialis, S. glacialis subsp. fontqueriana). This is evident in S. carpetana which has long trichomes at the base of non-woody twigs and other parts, as well as the holotrichous indumen- PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 154 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species tum, which is similar to taxa found in Mediterranean zones. This marked Med- iterranean character of Sierra de Guadarrama and its relationships with Sierra Nevada vegetation has been highlighted in recent revisions of high Iberian veg- etation (Gavilan et al. 2017). On the other hand, the rhizomatous habit is also a typical characteristic of orophilous taxa, for instance S. /urida (subsect. Lurida), found close to the Sierra de Gredos (Central System), grows in loose substrates (screes) similar to S. carpetana, although these are of geological origin and not anthropogenic, as in our case (Rivera and Ob6n 1990; Lucefio et al. 2000). A comprehensive flora checklist for the siliceous substrate, which is more prevalent along the Central System exists (Rivas-Martinez 1963; Sanchez-Mata 1988, Fernandez-Gonzalez 1988; Lucefo et al. 2000), while the scarce and dis- persed calcareous areas, which have a particular flora, have received less atten- tion. However, there have been recent discoveries of new plant species in those well-known areas, such as the Sierra de Guadarrama (Fernandez-Gonzalez and Izco 1989). In the uplands of La Flecha Pass, the marble outcrops are inter- spersed with the typical preponderance of orthogneisses that conceal the cal- careous landscape. Their preservation is currently a top priority in the Sierra de Guadarrama National Park. It has applied conservation measures to this nat- ural reserve, as outlined in the Spanish National Parks Law 30/2014, which in- clude several uses that are incompatible with the current management practic- es, such as public usage (visits) and substantial animal grazing (livestock). The area is currently described as having high ecological significance and unique natural assets that are of exceptional rarity, fragility, and scientific interest in order to ensure proper protection for these marble outcrops. Additional information Conflict of interest The authors have declared that no competing interests exist. Ethical statement No ethical statement was reported. Funding This work was supported by Universidad Complutense de Madrid. Project number PR3/23-30823. Author contributions JLI and RGG: conceived the paper; JLI. RMU, AGG, RGG: sampling in Sierra de Guadarra- ma; COC, DR, RGG: analyzed data by multivariate analyses and wrote the corresponding texts. RGG compiled the first versions of the text; All authors contributed to the writing in the last version; RMU: correct the English. Author ORCIDs Rosina Magana Ugarte © https://orcid.org/0000-0003-0628-3251 Alba Gutiérrez-Girdn © https://orcid.org/0000-0002-0988-3343 Concepcion Ob6n de Castro © https://orcid.org/0000-0002-0244-601X Diego Rivera Nufiez © https://orcid.org/0000-0001-6889-714X Rosario G. Gavilan © https://orcid.org/0000-0002-1022-445X PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 155 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species Data availability All of the data that support the findings of this study are available in the main text or Supplementary Information. 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Sideritis glacialis (incl. subsp. fontqueriana, S. fernandez-casasii) TERUEL: Puerto de Valdelinares, 30TYX07, 1800 m asl, in Junipero sabinae-Pin- etum sylvestris. Andrés Molina, 5-8-1982, MAF 120116; Altos de la Sierra de Gudar. Salvador Rivas Goday, 24-6-1946, MAF 77086; 4-7-1995, Valdelin- ares, Sierra de Gudar, estacioén invernal, Vicente Jesus Aran, MA561273; Valdelinares, proximo a la desviacion de Penaroya, 29-08-2002, J. Herrero, MA700968; Cerca de la Virgen de la Vega, Alcala de la Selva, Collado de la Gitana, 10-7-1946, Font Quer, Sierra y Torres, MA344902; Sierra de Gudar, 1900 m, 5-8-1974, G. Lopez & E. Valdés-Bermejo, MA435326. GRANADA: Sierra Nevada, 24-8-1977, E. Rico, MA 212210; Capileira, Sierra Nevada, Vasares del Veleta, laderas rocosas y pedregosas, micaesquistos, 3020 m asl, 19-8-1990, L.F. Sanchez & J.A. Alejandre, MA 493728 Sideritis hyssopifolia (incl. subsp. nocedoi) LEON: Boca de Huérgano, macizo de Pefia Prieta, roquedos calizos en laders de solana del valle de Lechada, 1970-2060 m asl, 16-7-1990, M.L. Gil Zuniga & J.A. Alejandre, MA493729; San Emiliano, Pena Ubina, SE, laderas pedregosas calcareas, 30TTN5967, 2000 m, 30-7-2001, V.J. Aran & M.J. Toha, MA691953; Circo Cebollero, Puerto de San Isidro, 27-7-1979, Casaseca, Fernandez, Amich, Rico & Sanchez, MA256354; Between Nocedo and Valdeteja, 1800 masl, 27- 8-1972, Salvador Rivas Goday and Jesus Izco. MA256357, ibidem MAF84289. Sideritis pungens (incl. subsp. javalambrensis, S. javalambrensis) TERUEL: Camarena de la Sierra, Javalambre peak, 30TXK6841, 2000 m asl, in lapidosis calcareis, 18-9-1981, leg. Santiago Castroviejo, Fernandez Quiros, det. José Borja. MAF 127937; ibidem MA381171; La Puebla de Valverde, cer- ro de Javalambre, junto a las instalaciones de television, 7-7-1995, Vicente Jesus Aran, MA561283; Sierra de Javalambre, 2000 m, 11-9-1900, F. Sennen, MA100605; Pico Javalambre, matorrales pulvinulares de Erodio-Erinacetum, 1-7-1983, Peris, Stubing & Gonzalez, MA479758. PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 158 Jose Luis Izquierdo et al.: Sideritis carpetana a new calcareous high-mountain Mediterranean species Supplementary material 1 Supplementary information Authors: Jose Luis Izquierdo, Rosina Magana Ugarte, Alba Gutiérrez-Girdn, Concepcion Obon de Castro, Diego Rivera Nunez , Rosario G. Gavilan Data type: pdf Explanation note: Detailed description on Sideritis carpetana. table $1. Data on taxa in- cluded in the multivariate analysis done to the Iberian Sideritis from high and medium altitudes. table S2. Comparison of Sideritis carpetana sp. nov. with other closely-re- lated taxa. Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited. Link: https://doi.org/10.3897/phytokeys.251.129982.suppl1 PhytoKeys 251: 143-159 (2025), DOI: 10.3897/phytokeys.251.129982 159