Dianthus borbonicus Brullo, C. Brullo, Colombo, Giusso, Ilardi & Perrone, 2015

Brullo, Salvatore, Brullo, Cristian, Colombo, Paolo, Galdo, Gianpietro Giusso Del, Ilardi, Vincenzo & Perrone, Rosaria, 2015, Dianthus borbonicus (Caryophyllaceae), a new species from Sicily, Phytotaxa 233 (1), pp. 49-60 : 50-58

publication ID	https://doi.org/ 10.11646/phytotaxa.233.1.3
persistent identifier	https://treatment.plazi.org/id/03B0422E-FFD0-FFC3-FF47-FC04C5B6FEE8
treatment provided by	Felipe
scientific name	Dianthus borbonicus Brullo, C. Brullo, Colombo, Giusso, Ilardi & Perrone
status	sp. nov.

Treatment

Dianthus borbonicus Brullo, C. Brullo, Colombo, Giusso, Ilardi & Perrone View in CoL , sp. nov. ( Figs.1 View FIGURE 1 , 2A–C View FIGURE 2 ).

Type:― SICILY. [Palermo] Ficuzza, Corona del Re presso Pizzo Morabito, su pareti calcaree esposte a Nord, a ca. 1150 m s.l.m., 37° 50′ 44′′ N, 13° 26′ 37′′ E, 10 June 2014, Brullo & Ilardi s.n. (holotype CAT!, isotypes CAT!, FI!).

Diagnosis: ― A Diantho cyathophoro differt caudice compacto, foliis basalibus 2−10(−11) cm longis, 2−4 mm latis, foliis caulinis 2−5(−6) cm longis, caule 6−25 cm longo, 1−4-floro, bracteis calycinis divaricatis vel patentibus, mucrone 0.5−2.0 mm longo, interioribus 10 mm longis, 12−13 mm latis, esterioribus 8−10 mm longis, 5.0− 7.5 mm latis, calyce 26−30 mm longo, 6.0− 7.5 mm diametro, anthera 3.5 mm longa.

Description (macro-morphology): ―Suffrutex, 15 − 30(− 35) cm tall; woody stocks densely branched, with branches 1 − 4 cm long. Basal leaves inserted along the woody stock branches, flat, 2 − 10(− 11) cm long, 2 − 4 mm wide, acute at the apex; cauline leaves 2 − 5(− 6) cm long. Stems 1 − 4-flowered, 6 − 25 cm long, with 4 − 5 internodes; epicalyx scales 4, divaricate to patent, with mucro 0.5 − 2.0 mm long; the inner ones subrounded to obovate, 10 mm × 12 − 13 mm, the outer ones ovate to subrounded, 8 − 10 × 5.0 − 7.5 mm; calyx 26 − 30 mm long, 6.0 − 7.5 mm in diameter, with teeths triangular, slightly membranaceous on the margin, acute, not overlapping, 6 − 7 mm long; petals 40 − 45 mm long, claw 25 − 30 mm long, limb purplish-pink, cuneate-rounded, 15.0 × 11 − 14 mm, with 20 − 34 teeth, 0.3 − 2.0 mm long, simple, triangular; anther pink-lilac, 3.5 mm long; ovary 8 − 10 mm long; style with stigma 20 − 24 mm long. Capsule cylindrical, 14–16 mm long included in the calyx.

Seed testa micro-morphology: ―According to literature (e.g., Yildiz 2002, Vural 2008, Yildiz & Güzel 2008, Ilçim et al 2013, Hamzaoğlu et al. 2015a, 2015b), the seeds of Dianthus are black, flat, peltate, cuspidate at apex, with coat made by elongate cells, which are undulate at the margins, and more or less minutely papillose. As concerns D. borbonicus , the seeds show a suborbicular to orbicular-ovate outline, and they are covered by irregularly elongate cells, which are loosely undulate at the margins, and have anticlinal walls represented by a deep and wide grooves, irregularly trabeculate, with U- to S-like undulations, while the periclinal walls are minutely papillose and colliculate, with one or two series of colliculi ( Fig. 3A View FIGURE 3 ). In addition, the cells on the dorsal face are shorter than those in the centre (75−110 μm) ( Fig. 3A View FIGURE 3 2 View FIGURE 2 ) and longer than the cells on the margins (130−260 μm) ( Fig. 3A3 View FIGURE 3 ), while they are morphologically uniform in ventral portion (60−130 μm) ( Fig. 3A View FIGURE 3 5 View FIGURE 5 ).

The seeds of the two closely related species [ D. busambrae Soldano & F. Conti (2005: 18) and D. minae Mazzola, Raimondo & Ilardi (2004: 307) ] were examined for a comparison. Actually, they are quite similar to those ones of D. borbonicus ( Fig. 3B View FIGURE 3 ), but some important differences occur. D. busambrae shows seeds ovate, with testa characterized by very irregular cells in the dorsal face, isodiametric to elongate in the cental part (55−100 μm), tightly undulate at the margin, having anticlinal walls represented by a deep and narrow grooves, not trabeculate, with U- or Ω- like undulations ( Fig. 3B View FIGURE 3 2 View FIGURE 2 ), while in D. minae , the peripherical cells are elongated (55−130 μm), with anticlinal walls having S- or U-like undulations ( Fig. 3B3 View FIGURE 3 ). As concerns the periclinal walls, they are very similar to those ones of D. busambrae , but always with one series of colliculi. Cells of the ventral face are very homogeneous, elogated (80−150 μm), with anticlinal walls usually having U-like undulations ( Fig. 3B View FIGURE 3 5 View FIGURE 5 ). Seeds of D. minae are, instead, ovate-lanceolate ( Fig. 3C View FIGURE 3 ), with irregularly elongated cells in the dorsal face, shorter in the centre (75−120 μm), tightly undulate at the margin ( Fig. 3C View FIGURE 3 2 View FIGURE 2 ). Anticlinal walls are made by deep and very narrow grooves, not trabeculate, with V- or U-like undulations, while the periclinal walls are very similar with only one series of colliculi ( Fig. 3C3 View FIGURE 3 ). Cells of the ventral face are elongated and more or less uniform 130−200 μm), with grooves of the anticlinal walls more spaced showing usually U-like undulations ( Fig. 3C View FIGURE 3 5 View FIGURE 5 ).

Leaf anatomy: ―Leaves in Dianthus borbonicus appear asymmetrical from the macro-morphological point of view. However, in cross section. they show the typical arrangement of the isobilateral structure ( Fig. 4A View FIGURE 4 ). It can be considered amphistomataous, with the palisade layer distributed along the whole surface, the abaxial face differing from the adaxial one only concerning a central prominence due to the midrib. The epidermis is 1-layered with a well developed cuticle and numerous sunken stomata. The external parenchyma is represented by a palisade, usually 3-layered (sometimes 2-layered), more developed in the adaxial face, thinning at the margins and on the abaxial face in correspondence of the midrib. The spongy tissue is no chlorenchymatous and occupies the central part of the leaf wrapping the vascular bundles. There are three main vascular bundles, of which the larger one is placed in correspondence of the midrib and two smaller ones at the margins. Other small vascular bundles (six for each side) are distributed among the mian three. In particular, the three largest vascular bundles, which like all the others have the phloem toward the abaxial face, are surrounded externally by a crescent-shaped calotte of sclerenchymatous fibres. Moreover, a sheath of large cells containing drusen of calcium oxalate is set along the outer surface of the calotte. This anatomical structure is very similar to that concerning the leaves of D. busambrae . Main differences concerning: the smaller size in D. borbonicus , with a shape almost flat with an angle of ca. 170°−180°, midrib little protruding, the vascular bundle corresponding much smaller, a more developed palisade (usually 3-layered) and not more than six secondary vascular bundles for each side. On the contrary, D. busambrae is characterized by larger leaves, canaliculate with an angle of ca. 140°, midrib much more developed and protruding, the vascular bundle corresponding much larger with diameter almost double, the palisade less developed (usually 2-layered) and 7−8 secondary vascular bundles per side ( Fig. 4B View FIGURE 4 ). Much more remarkable differences can be observed in the leaves of D. borbonicus if they are compared woth those of D. minae . This latter species shows leaves less wide and very thick, canaliculate with an angle of 135°−140°, main vascular bundles with a diameter more than twice and the vascular bundles of the second order less numerous (3−5 per side), epidermis with larger cells and thicker cuticle, spongy tissue wider ( Fig. 4C View FIGURE 4 ). Overall, D. minae seems to be more closely related to D. arrosti C. Presl (1822: 60) ( Fig. 4D View FIGURE 4 ). Actually, the two species show remarkable similarities in the leaf shape and tissue arrangement, even if significant structural differences can be observed, such as the leaf thickness and outline, distribution and size of the palisade and spongy tissues, and number of the second order vascular bundles.

Etymology: ―The epithet refers to the Bourbon Royal Family (in Latin “Borbonicus ”), who had a game reserve and a Royal Palace in Ficuzza, (near Palermo) where the new species grows.

Phenology: ―Flowering late May‒early June; fruiting late June‒July.

Habitat and distribution: ― Dianthus borbonicus is a very rare chasmophyte localized on Mesozoic northfacing limestones of a rocky walls at 1100−1150 m a.s.l. ( Fig. 2A View FIGURE 2 ). On the basis of our field investigations, it grows exclusively on a rocky outcrop near Pizzo Morabito at the forested area of Ficuzza (Palermo Province, North-Western Sicily). It is interesting to note that other rare endemics occur, such as Anthemis cupaniana Todaro ex Nyman (1879: 360) , Centaurea busambarensis Gussone (1845: 873) , Helichrysum pendulum (C. Presl 1822: 97) C. Presl (1826: 29) , and Athamanta sicula Linnaeus (1753: 244) .

Conservation status: ―Only one site is currently known for Dianthus borbonicus (the Ficuzza-Rocca Busambra Natural Reserve, Fig. 5 View FIGURE 5 ). Despite the population is small, being represented by about 100 individuals, which occupy an area of about 10.000 mq, it does not seem that it are seriously threated by human activities. Furthermore, considering the remarkable conservativeness of the rupestrian environments and the long life span of the plant, only occasional events (such as fires), may cause a decreasing of the number of mature individuals. According to the criterion “D”. we propose to consider this species as “Endangered” and to include it, for its rarity and punctiform distribution, into the category EN D ( IUCN 2014).

Discussion: ― Dianthus is one of the most critical genera in Caryophyllaceae Juss. , being represented by several and poorly investigated groups. From the morphological point of view, important characteristics concern the shape of calyx, calyx, epicalyx scales and corolla ( Bacchetta et al. 2004, 2010). Based on these features, D. borbonicus has to be included into the D. sylvestris group, which shows a high diversity in the central Mediterranean area. The new species seems to be closely related to D. cyathophorus Moris (1852: 32) from Sardinia, with which it shares the epycalyx scales markedly divaricate, morphological feature rather unusual in Dianthus . However, D. cyathophorus differs from D. borbonicus in having a larger size (40−70 cm tall), flat leaves, 10−25 cm long, epicalyx scales with mucro 3−4 mm long, calyx 22−25 mm, petals 30−35 mm long, with limb 9−10 mm wide and anthers 4 mm long ( Fig. 6A View FIGURE 6 3−D3 View FIGURE 3 ). A further similar species is D. minae , which was described from northern Sicily (Mts. Madonie). Due to its remarkable morphological similarity, D. minae was previously considered by Bacchetta et al (2010) a synonym of D. cyathophorus , but ongoing field investigations revealed that they are two well distinct species (features concerning the shape and size of leaves, epicalyx scales, calyx, petals and anthers, see Table 2). D. borbonicus shows significant differences in comparison with both D. cyathophorus and D. miniae , since its compact woody stock, shorter stems and leaves, different shape and size of the epicalyx scales, longer petals and shorter anthers. In particular, D. borbonicus differs from D. minae also in other features, such as leaves more or less flat not canaliculate, few-flowered stems (1−4), epicalyx scales larger and usually subrounded, calyx with a greater diameter, petals longer and wider, with teeth much more numerous ( Fig. 6A View FIGURE 6 2−D2 View FIGURE 2 ). The phenology, leaf anatomy and seed testa sculptures represent further differences. In fact, D. minae is an early flowering species (from early May to early June), with leaves anatomically very different from those ones of D. borbonicus , but very similar to those of D. arrosti , and seed coat with anticlinal walls formed by deep and very narrow grooves, not trabeculate. On the contrary, the suffruticose habit, well developed calyx, shortly mucronate epicalyx scales and a very similar leaf anatomy of D. borbonicus make the latter species more similar to D. busambrae , a chasmophyte localized on the rupestrian stands of the neighbouring Rocca Busambra. Actually, it has to be emphasized that the morphological differences between the two species are quite remarkable. They are mainly concerning the woody stock very loose with more developed stems, leaf canaliculate and longer, epicalyx scales appressed and transversally elliptical, calyx teeth overlapping, petals very shorter, cuneate, with limb narrower and having few teeth, anthers and ovary shorter in D. busambrae ( Fig. 6A View FIGURE 6 4−D4 View FIGURE 4 ). Furthermore, the latter is characterized a later flowering period (mid June to July), by relevant differences in the leaf anatomy and seed coat, which are characterized by anticlinal walls with deep and narrow grooves, not trabeculate, with U- or Ω- like undulations.

Additional specimen examined (paratype): ― SICILY. Ficuzza, Corona 1 del Re presso Pizzo Morabito, su pareti calcaree esposte a Nord, a ca. 1150 m. di altitudine, 29 June 2011, Brullo, Colombo, Perrone & Ilardi s.n. (CAT!).