Sideritis carpetana Izquierdo & Gavilán, 2025

Izquierdo, Jose Luis, Magaña Ugarte, Rosina, Gutiérrez-Girón, Alba, Obón de Castro, Concepción, Rivera Núñez, Diego & Gavilán, Rosario G., 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, pp. 143-159 : 143-159

Sideritis carpetana Izquierdo & Gavilán sp. nov

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 cylindric 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 × 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. material 1: table S 1 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 anthropogenic 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 (ETRS 89), Rosario G. Gavilán and José Luis Izquierdo, MAF [ MAF 181439 ].

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 typical of a Mediterranean territory.

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 plateau in central Iberian Peninsula. The Sistema Central comprises several mountain ranges: Sierra de Estrela, Sierra de Gata, Peña de Francia, Sierra de Gredos, Sierra de Guadarrama and Sierra de Ayllón from western to eastern territories.

Figures

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 ordination 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.

Figure 5. Sideritis carpetana natural habit in the marble anthropogenic outcrops of La Flecha Pass (Sierra de Guadarrama National Park).