Silene peloritana C.Brullo, Brullo, Giusso, Miniss. & Sciandr, 2014

Brullo, Cristian, Brullo, Salvatore, Galdo, Gianpietro Giusso Del, Minissale, Pietro & Sciandrello, Saverio, 2014, Silene peloritana (Caryophyllaceae) a new species from Sicily, Phytotaxa 172 (3), pp. 256-264 : 257-260

Silene peloritana C.Brullo, Brullo, Giusso, Miniss. & Sciandr , sp. nov. ( Figs. 1 , 2 )

Type: — ITALY. Sicily: Parte sommitale di Monte Scuderi (Catena dei Peloritani presso Messina), su affioramenti calcarei, 38° 04’ 13.28’’ N, 15° 24’ 26.53’’ E, 7 May 2012, Giusso del Galdo , Minissale & Sciandrello s.n. . (holotype, CAT!; isotypes, CAT!, FI!) .

Diagnosis: — A Sileni colorata differt caule prostrato-adscendente, prope basim ramoso, 5–10(–15) cm longo, dense piloso-pubescente, pilis usque ad 1.5 mm longis, internodis 3–35 mm longis, foliis spathulatis vel lanceolatis, piloso-ciliatis, obtusis,, floribus (1–) 2–5 in monochasio dispositis, calice 8–11 mm longo, dentibus ovato-triangularibus, rotundatis, lobis petalorum minoribus, eroso-undulatis, squamis coronulae purpureis, eroso-incisis superne, ungue glabro dorsaliter, anthera breviori, roseo-violacea, carpophore breviore et seminibus minoribus.

Description: —Annual herb 5–10(–15) cm tall, purplish-green, prostrate-ascending, with stems very branched at the base and sometimes at the nodes, densely pilose-pubescent, with indumentum hairs up to 1.5 mm long. Lower internodes 3–10 mm long, upper ones 10–35 mm long. Leaves spathulate to lanceolate (6–25 × 2–6 mm), flat, thin, obtuse, petiolate, 1-nerved. Inflorescence compact, (1–)2–5 flowered. Bracts lanceolate, 2–6 mm long. Flowers erect, in terminal helicoid monochasia; pedicuncles 1–8 mm long; calyx 8–11 mm long, minutely pubescent, subtubulose, purplish-green, umbilicate at the base, 10-nerved, without anastomoses, teeth 1.2–1.8 × 1.2–1.8 mm, ovate-triangular, rounded, with margin membranous, shortly ciliate; petals 14–15 mm long with limb of 6–7 mm, deeply 2-lobed, purplish-pink, and lobes 3–4 × 2.8–3.2 mm in size, obovate, undulate-erose above, coronal scales 2–2.2 mm, purplish, shortly retuse, eroseincised above; claw 7–8 mm, white, 3-nerved, glabrous dorsally; stamens shorter than petals with filament 8–9 mm long, white and anthers pink-violet, 1.5–1.6 mm long; ovary 3–3.5 mm long, glabrous, green; styles 3, filiform. Capsule ellipsoid-ovoid (7–8 mm long); carpophore 3.5–4.5 mm long, pubescent; seeds 1.3–1.5 mm in diameter, pale brown, orbicular-reniform, flat laterally, winged and deeply canaliculate dorsally, and with wings undulate.

Phenolgy: — Silene peloritana produces flowers from late April to May and fruits from May to June.

Habitat and distribution: — Silene peloritana grows on the summit of Mt. Scuderi ( NE Sicily) at an elevation of 1000–1250 m a.s.l., on carbonatic outcrops densely covered by mosses. It is usually a member of therophytic plant communities characterized by xerophilous microphytes with the dominance of Poa bulbosa Linnaeus (1753: 70) .

IUCN Red List Category: —The growing site of Silene peloritana is Mt. Scuderi, an isolated peak of Peloritani range (maximum altitude is 1253 m a.s.l.) where, in spite of its relatively small area, there is a high plant diversity, including a rich endemic flora, mainly of exclusive species [e.g., Asperula peloritana C.Brullo, Brullo, Giusso & Scuderi (2009: 86) , Plantago peloritana Lojacono-Pojero (1907: 35) , Hieracium hypochoeroides Gibson (1843: 741) subsp. montis-scuderii Di Gristina, Gottschilich, Galesi, Raimondo & Cristaudo (2013: 50), and Thapsia garganica Linnaeus (1767: 57) subsp. messanensis (Gussone 1843: 359) Brullo, Guglielmo, Pasta, Pavone & Salmeri (2009: 45) ]; several other narrowly distributed and phytogeographically relevant taxa there are in the same site or in other carbonatic outcrops of the Mts. Peloritani, such as: Adenocarpus commutatus Gussone (1828: 375) , Brassica raimondoi Sciandr., C.Brullo, Brullo, Giusso, Miniss. & Salmeri (2013: 813) , Festuca humifusa Brullo & Guarino (2001: 409) , Centaurea gussonei Raimondo & Spadaro in Giardina et al. (2007: 10), Edraianthus siculus Strobl (1883: 66) , Linum punctatum C.Presl in Presl & Presl (1822: 58), Onosma echioides ( Linnaeus 1753: 173) Linnaeus (1762: 196) subsp. canescens ( Presl 1826: 34) Peruzzi & Passalacqua (2008:772) , Viola messanensis (Beker 1905: 359) Brullo in Bartolo et al. (1994: 403), Plantago humilis Jan ex Gussone (1827: 192) , Pimpinella tragium Villars (1779: 24) subsp. glauca ( Presl 1822: 125) Brullo & Brullo (2009: 44) , Acinos alpinus ( Linnaeus 1753: 591) Moench (1794: 407) subsp. nebrodensis (A.Kern. & Strobl in Kerner 1874: 171) Brullo & Brullo (2009: 43), Dianthus arrosti Presl (1822: 60) , and Centaurea seguenzae ( Lacaita 1915: 246) Brullo et al. (2004: 489) .

From the biogeographical point of view, the population of Silene peloritana falls within the Peloritan district, belonging to the Eu-Sicilian sector ( Brullo et al. 1995). This district represents a part of the island (the north-east), where the pool of endemics (16 narrow endemics) is comparable to other districts of Sicily ( Sciandrello et al. 2014), such as the Hyblaean district, including 15 narrow endemics ( Brullo et al. 2011). This plant diversity is rather high, considering that this district is a mountain area with few peaks ranging from 1000 and 1370 m a.s.l., and mainly constituted by Palaeozoic metamorphic and granitic rocks mixed to scattered carbonatic Mesozoic outcrops.

Due to its rarity and low number of individuals, Silene peloritana should be classified, according to the IUCN criteria (2010), as endangered species: EN C2a(ii).

Etymology: —The specific epithet refers to “Peloritani”, mountain range of north-eastern Sicily.

Seed morphology: —The seed micro-morphology has an high taxonomic value in the genus Silene ( Berggren 1981, El-Oqlah & Karim 1990, Hosny & Zareh 1993, Villa 1995, Yildiz & Cirpici 1998, Hong et al. 1999, Zareh 2005, Yildiz 2006, Yildiz & Minareci 2008, Perveen 2009, Fawzi et al. 2010, Ocaña et al. 2011, Brullo et al. 2012, Peruzzi & Carta 2013), also having a phylogenetic relevance ( Johnson et al. 2004, Attar et al. 2007, and Moazzeni et al. 2007). The main and useful character are the seed testa ornamentations. Our SEM analysis highlighted that seeds are 1.3–1.5 mm in diameter, orbicular-reniform, flat, concave laterally, winged and deeply canaliculate dorsally, with wings more or less undulate ( Fig. 3A–B ). The seed coat is characterized by very elongated epidermal cells (100–150 × 10–20 µm), sparsely tuberculate and irregularly lobate at the margin ( Fig. 3D ). The outer periclinal wall is indistinguishable colliculate, loosely and minutely granulate on the surface, while the anticlinal wall boundaries are irregularly lobate, depressed, with deeply lacerate sutures. At the bottom of the dorsal furrow, the epidermal cells have indistinguishable margins subcircular, arranged in 3–4 rows, usually mono-tuberculate and densely covered by papillae ( Fig. 3B ).

Taxonomic relationships: — Silene peloritana appears well differentiated from the other species of the S. sect. Dipterosperma in several distinctive features chiefly regarding the habit, the flowers, the capsules and the microsculptures of seed testa. In particular, it differs from the allied Sicilian species (e.g., S. colorata , S. nummica , S. arghireica and S. kemoniana ) in having shorter internodes, calyx teeth and petal limb, petal lobes obovate, undulate erose below, and anthers shorter, pinkish-violet ( Table 1).

S. kemoniana , a species also growing on mountain stands clearly differs from S. peloritana by the longer internodes, bracts, calyx, calyx teeth and petals, petal limb deeply lobed, with narrower lobes oblong and rounded calyx teeth, petal lobes very narrow and smooth, coronal scales white, anthers longer, ovary shorter, capsule and seeds bigger ( Table 1). More differences can be observed between S. peloritana and S. colorata , this latter a species widespread in the whole Mediterranean area, where it preferably grows on coastal sandy habitats. S. colorata is erect, minutely pubescent, not or few branched at the base, with leaves linear-spathulate, acute to apiculate at the apex, inflorescences arranged in loose many-flowered dichasia, calyx and its teeth longer, petal lobes longer, oblong and smooth, petal claw dorsally hairy, coronal scales white and smooth, anther yellowish-green and longer, ovary shorter, and seeds carpophore longer. Also S. nummica and S. arghireica show morphological and ecological differences against S. peloritana . These two species are extremely rare in Sicily, occurring in coastal areas, and they show habit, size and shape of the flower pieces extremely peculiar. S. nummica is prostrate, with succulent and widely spathulate leaves, flowers usually solitary, calyx tomentose-hirsute, calyx teeth longer, petal lobes longer, smooth, petal claw hairy, coronal scales shorter, white and smooth, ovary and capsule shorter, anthers and carpophore, seeds smaller, while S. arghireica is erect with leaves always lanceolate, subacute, flowers in dichasia arranged, calyx and teeth longer, petal longer, petal lobes hemielliptical longer, smooth, petal claw longer, coronal scales, longer, 2-lobed, smooth and divaricate, anthers, ovary and carpophore longer ( Table 1).

According to Brullo et al. (2012, Fig.3 ), S. peloritana shows some other relevant differences in the micro-sculptures of the seed testa, when compared with the allied Sicilian species. In particular, S. colorata has seeds with epidermal cells shorter and wider (65–110 × 22–30 µm), outer periclinal walls clearly colliculate, minutely and densely granulate, anticlinal wall boundaries slightly undulate, flattened, not lacerate, narrower and granulate, cells at the bottom of dorsal furrow are bigger and arranged in 2 rows. Moreover, there are relevant differences with S. kemoniana , which has bigger seeds than S. peloritana , outer periclinal walls markedly colliculate, anticlinal wall boundaries irregularly incise-undulate, canaliculate, while cells at the bottom of the dorsal furrow are smaller and irregularly arranged in 2–3 rows, with one central papilla and interspersed with numerous minute wrinkles. According to Villa (1995), also S. nummica and S. arghireica show remarkable differences in the seed testa than S. peloritana .

Figures

FIGURE 1. Silene peloritana. A. Habit. B. Flower. C. Corolla. D. Open calyx. E. Petal (dorsal view). F. Petal (ventral view). G. Petal (lateral view). H. Coronal scale. I. Anther. J. Pistil. K. Capsule with calyx. L. Close capsule. M. Open capsule. N. Seed (lateral view). O. seed (dorsal view). Illustration by Salvatore Brullo based on type specimen (CAT).

FIGURE 2. Silene peloritana. A. Mt. Scuderi (NE Sicily). B. Flower detail (lateral view). C. Flower detail (above view). D. Habit. (Photos: P. Minissale).

FIGURE 3. SEM micrographs of seed testa of Silene peloritana. A. Seed (lateral view). B. Seed coat detail (dorsal view). C-D. Seed coat detail (lateral view).