Centaurea haluntina Gianguzzi, Di Grist., Barone, Domina

Gianguzzi, Lorenzo, Gristina, Emilio Di, Barone, Giulio & Domina, Gianniantonio, 2024, A new species of the Centaurea busambarensis complex (Asteraceae) from the Nebrodi Mountains in Sicily (Central Mediterranean region), Phytotaxa 646 (2), pp. 169-180 : 177-178

Centaurea haluntina Gianguzzi, Di Grist., Barone, Domina , sp. nova.

Type:— ITALY. Sicily: San Marco d’Alunzio (ME), c.da Grilli , cliffs, 38.083779° N, 14.700798° E, 300 m a.s.l., 5 June 2023, L. Gianguzzi, E. Di Gristina, G. Barone, G. Domina s.n. (holotype SAF100120 ; isotypes FI, PAL-Gr, PI064712 ) .

Other studied material (paratype):— ITALY. Sicily: S. Marco D’Alunzio, lungo la strada verso Capri Leone (ME), sulle rupi, 28.12.199 4, L. Gianguzzi s.n. (PAL83369, sub. C. todaroi Lacaita ).

Iconography:— Figure 7 .

Diagnosis:—Planta incana, foliis 1-pinnatipartitis (rare 2-pinnatipartitis), griseo-virescentis. Corymbus 4–11 capitulis; involucra ovata, 14–17 × 14–17 mm. Appendices fuscae vel nigrae; fimbriae rectae, 6–9 utroque latere, 1.7–2.7 mm longae. Flosculi roseo-lilacini; achenia 3.8–5.0 × 1.1–1.7 mm; pappus 3.8–5.2 mm longus.

Etymology:—The specific epithet refers to “Haluntium”, the Roman name of the present-day village of San Marco d’Alunzio where the species here described was found.

Description:—Perennial plants up to 70(90) cm ( Figure 9a ), rosette-forming. Stem erect, white-tomentose, with few branches above. Rosette leaves lyrate, 1(–2)-pinnatisect, gray-green, with downy hair, 14–25(–38) cm long, 3– 8(–10) cm large with 4–7 pairs of lobes. Cauline leaves 1(–2)-pinnatisect, with sinuate margins, gray-green, 4–7.5 mm long, 3–5.5 mm wide ( Figure 9b ). Branch leaves entire, 25–50 mm × 25–50 mm. Capitula in clusters of 4– 11. Peduncles 1.5–3 mm wide, with sparse leaves. Involucre ovoid, 14–17 × 14–17 mm ( Figure 9c ); bracts ovatelanceolate, glabrescent to arachnoid-hairy, with 7–9 nerves on the back. Appendages dark brown to black, shortly decurrent at the base, fimbriate. Appendages below the fimbria, with margins 0.5–1 mm wide. Fimbriae straight, 6–9 on each side, 1.7–2.7 mm long. Florets pink-violet, 14–18 mm long. Achenes light brown, 3.8–5.0 mm long, 1.1–1.7 mm wide. Pappus white, 3.8–5.2 mm long.

Life form:—Chamaephyte rosulate with chasmophyte habit.

Phenology:—Flowering and fruiting period: May to July.

Chorology and ecology:—So far, Centaurea haluntina has been found in the Nebrodi Mountains in the northeastern part of Sicily. The studied population located in the municipality San Marco d’Alunzio comprises approximately 1000 mature individuals and covers an area of roughly 5000 square meters. Given that the habitat, steep and rugged, is represented in the territory on several hectares, it is possible that the mountain complex could potentially harbour additional subpopulations of this species.

The locality where the species was found is geologically linked to the carbonate complex of the Rocche del Crasto. It occurs in the lower part of the Tyrrhenian side of the Nebrodi Mountains, in the territory of S. Marco d’Alunzio, at elevations between 250 and 300 m a.s.l. above the Vallone Platanà, within the subunit “Lower Nebrodi” as recognized by Domina et al. (2018). These carbonates are dolomitic limestones of the lower Lias referring to the Longi-Taormina Unit (Kabilo-Calabridi Unit), made up in particular of greyish detrital limestones, algal biocalcarenites and gray-whitish oosparites sometimes dolomitized from massive to stratified in large banks, passing laterally to “black limestones” ( Lentini et al. 2000). Centaurea haluntina colonizes more or less steep (average slope 30–90°) and cracked rock faces, in areas relatively sheltered from the cold northern winds ( Figure 9 d ). From a bioclimatic point of view, the area falls within the upper thermo-Mediterranean range (average temperatures around 16.3 °C), with an upper subhumid ombrotype (average rainfall around 750 mm: Gianguzzi 2007, Gianguzzi et al. 2016).

The species takes part in aspects of chasmophytic vegetation phytosociologically attributable to the alliance Dianthion rupicolae (class Asplenietea trichomanis), which is accompanied by various typical elements such as: Scabiosa cretica , Dianthus rupicola subsp. rupicola , Silene fruticosa , Sedum sediforme , Galium lucidum , Micromeria consentina , Melica minuta , Phagnalon saxatile , Anthirrhinum siculum , as well as Lobularia maritima , Ruta chalepensis , Prasium majus , Teucrium fruticans , Sedum dasyphillum subsp. glanduliferum , Ballota rupestris , etc. On the rocky ledges and in the upper part of the cliffs this vegetation comes into contact with aspects of scrub of the Ruto chalepensis-Oleastretum sylvestris ( Gianguzzi & Bazan 2019, 2020).

Figures

FIGURE 7. Centaurea haluntina Gianguzzi, Di Grist., Barone & Domina: a) habit; b) rosette leaf; c) capitulum; d) phyllary; e) cypsela (drawn by L. Gianguzzi from the original material).

FIGURE 9. Centaurea haluntina Gianguzzi, Di Grist., Barone & Domina: a) habit; b) cauline leaf; c) capitulum; d) habitat.