Centaurea pandataria (Fiori & Béguinot) Béguinot (1905: 443)

Brullo, Salvatore, Cambria, Salvatore, Crisafulli, Alessandro, Tavilla, Gianmarco & Sciandrello, Saverio, 2021, Taxonomic remarks on the Centaurea aeolica (Asteraceae) species complex, Phytotaxa 483 (1), pp. 9-24 : 17-19

2. Centaurea pandataria (Fiori & Béguinot) Béguinot (1905: 443) ( Figs. 2 , 4B , 7B, D )

≡ Centaurea cineraria var. pandataria Fiori & Béguinot in Fiori & Paoletti (1904: 334) ≡ Centaurea aplolepa subsp. pandataria (Fiori & Béguinot) Dostál (1976: 202) ≡ Centaurea aeolica subsp. pandataria (Fiori & Béguinot) Anzalone (1995: 512) .

Type:— ITALY. Latium: Herbarium Insularum Pontianum, Sulle rupi maritime a Ventotene , 20 September 1901, A. Béguinot s.n. (lectotype FI 051939!, designated here) .

Description: —Perennial herb with a woody rootstock. Stems erect, striate, with greenish-grey to greyish tomentum, 30–60 cm tall and 2–4 mm in diameter, simple, leafy. Leaves tomentose, greenish-grey to greyish; basal leaves usually on short sterile branches, more or less petiolate, usually sublyrate, 1-pinnatisect, the primordial ones often are entire, 3.5–18 × 1.5–5.5 cm, with lateral laciniae linear, 1–3.5 cm long, 1–6.5 mm wide, apex obtuse to rounded, shortly mucronulate, terminal lacinia oblanceolate to lanceolate, 2–6.5 × 0.4–2.4 cm; cauline leaves short petiolate to subsessile, 1-pinnatisect to entire, oblanceolate in outline, 1–10 cm long, with laciniae 1–2.6 cm long, 1–5 mm wide, linear-lanceolate to linear, apex obtuse to rounded, shortly mucronulate. Capitula arranged in terminal racemes, ovoid, 10–15 mm long, 7–9 mm in diameter; phyllaries imbricate up to 60, powdered, dorsally convex, usually 5-nerved, with terminal appendages triangular, pale brown and blackish at the apex, 0.2–0.7 mm long, with 2–5 teeth, 0.1–0.3 mm long, usually with a single short mucro in the innermost phyllaries; outer phyllaries ovate, 3–4 × 1.5–2.2 mm; median phyllaries ovate-lanceolate, 5–9 × 2.2–3.2 mm; inner phyllaries linear-lanceolate, 9–12 × 1.3–2.2 mm. Florets purplish-pink; ray florets sterile, 20–21 mm long, with lobes unequal, 6–8 mm long; disc florets fertile, 17–18 mm long, with lobes equal, 2.8–4.5 mm long; stamens 18 mm long, with filaments 12.5 mm long, fused below, free and hairy above, anthers 6.5 mm long. Style 18 mm long, ciliate at apex; stigmatic branches 2 mm long. Achenes oblong, 3.5–4 × 1.3–1.5 mm, sparsely villous, brownish, coronula short, straw-coloured, with several irregular straw-coloured longitudinal ridges; pappus biseriate, whitish, outer series 0.1–0.5 mm long, inner series 0.8–1.5 mm long.

Etymology: —The specific epithet derives from “ Pandataria ”, Latin name of the Ventotene island of the Ponziano Archipelago (Latium), where this species occurs.

Phenology: —The species flowers from June to July and fruits from June to July.

Distribution and ecology: — Centaurea pandataria is restricted to Ventotene (Ponziano Archipelago), which constituted by volcanic islands near the Tyrrhenian coast of Latium (Central Italy). Currently, it occurs in a short stretch along the north-western coast of the island, where it prefers steep and inaccessible sea cliffs ( Fig. 5 ); sometimes it grows in uncultivated lands and along roadsides. This species is a member of a subhalophilous vegetation characterized by Jacobaea maritima ( Linnaeus 1753: 925) Pelser & Meijden (2005: 677) subsp. bicolor ( Willdenow 1803: 2085) B. Nordenstam & Greuter (2006: 712) , Helichrysum litoreum Gussone (1844: 468) , Crithmum maritimum Linnaeus (1753: 246) , Daucus gingidium Linnaeus (1753: 242) , Artemisia arborescens Linnaeus (1763: 1188) , etc.

Conservation status: — Centaurea pandataria is assessed by Conti et al. (1997) as Vulnerable (VU), while Orsenigo et al. (2018) classified it as Near Threatened (NT), highlighting recreational activities (6.1) as a possible threat. Both conflicting opinions are not supported by a detailed analysis of the unique known population. Based on our observations and considering the IUCN criterion B ( IUCN 2020), C. pandataria is mainly confined to the cliffs of the island’s northern coast, with a very small Area of Occupancy (AOO = 12 km 2). Moreover, as this is a natural environment threatened above all by erosion phenomena (landslides), fires and anthropic pressure (agriculture and urbanization), we propose to include this species in the category Endangered (EN) B2ab (ii, iii).

Taxonomic notes: —From the taxonomic point of view, Centaurea pandataria was usually considered closely related to C. aeolica or even its synonym ( Fiori 1927, Cela Renzoni & Viegi 1982). However, several significant morphological features allow to separate it at the species level as proposed by Béguinot (1905) and recently confirmed by molecular studies of Hilpold et al. (2011). In particular, for its shape of leaves and extremely reduced phyllary appendages, often represented by a mucro, C. pandataria seems to be quite isolated within the Centaurea cineararia group. Concerning the lectotypification of C. pandataria , this taxon was described by Fiori & Béguinot (cf. Fiori 1904a) as C. cineraria var. pandataria on the herbarium material collected in Ventotene by Béguinot. Later, Béguinot (1905) treated it as a distinct species “ Centaurea pandataria ”, stating that he collected it for the first time in Ventotene in May 1900 and then in September 1901. Currently, three specimens belonging to the original collections of Béguinot are kept in the Florence Herbarium (FI), among them the sheet number 051939 identified by Béguinot as “ C. aplolepa Moretti var. pandataria Nob. ?” is here designated as lectotype.

Specimens examined: — ITALY. Latium: Herbarium Insularum Pontianum, Ventotene sulla scogliera sotto il Montagnozzo , 20 September 1901, A. Béguinot s.n. (FI 051938!) ; ibid. Ventotene sulle rupi marittime presso il Semaforo, 25 May 1900, A. Béguinot s.n. (FI 051937!) ; ibid. Isole Ponziane, Isola di Ventotene , by the “Centro Educazione Ambientale”, about 0.7 km SW Semaforo, shruberry above the cliffs, 130 m, 23 May 2008, A. Hilpold V- 1113 ( BC947313 , B100663192) ; ibid. Arcipelago Ponziano, Isola di Ventotene ( Latina ), 19 July 2020, G. Tavilla s.n. (CAT!)

Figures

FIGURE 2. Centaurea pandataria. A. Habit. B. Capitulum. C. Appendages of the phyllaries. D. Ray sterile floret. E. Disc fertile florets. F. Stamen. G. Stygma. H. Achenes with pappus. Illustration by S. Brullo based on living material coming from Ventotene collected by Tavilla (CAT!).

FIGURE 4. Variability of the phyllaries in Centaurea aeolica (A), Centaurea pandataria (B) and Centaurea phalacrica (C). Illustration by S. Brullo based on living material coming from the same locality as quoted in Fig. 1, 2, 3 (CAT!).

FIGURE 5. Geographical distribution of Centaurea aeolica (blue dots), C. pandataria (red dot) and C. phalacrica (green dot) based on herbarium materials and literature data.

FIGURE 7. A. Basal leaves of C. aeolica from Lipari island. B. Basal leaves of C. pandataria from Ventotene island. C. Capitulum of C. aeolica from Lipari island. D. Capitulum of C. pandataria from Ventotene island. (Photos by G. Tavilla).