Epipactis hyblaea Brullo & Zimmitti, 2014

Brullo, Salvatore & Zimmitti, Angelo, 2014, Epipactis hyblaea (Orchidaceae; Epidendroideae; Neottieae) a new species from Sicily, Phytotaxa 186 (1), pp. 42-50 : 42-48

Epipactis hyblaea Brullo & Zimmitti , sp. nov. (Figs. 1,2,3)

Type:— ITALY. Sicily: Siracusa, lecceta fresca su substrato calcareo all’interno della Riserva Naturale Orientata “Pantalica, Valle dell’Anapo e Torrente Cava Grande”, 24 May 2012, Zimmitti s.n. (holotype, CAT) .

Diagnosis: —Similar to E. distans from which it differs in having stem usually solitary, higher number of basal sheaths, smaller median cauline leaves, which are erect-divaricate to patent and laxly denticulate at margin, sepal smaller, green, ovate to ovate-lanceolate, petal smaller, hypochile larger, epichile longer with more numerous evident plicae in the protuberances, small ovary with longer pedicel; in addition, it is early flowering and grow in shady underwood habitats.

Perennial herbs with an elongate rhizome. Stem 25–60(–73) cm tall, usually solitary, rarely 2–3, erect, rigid, glabrous below, minutely pubescent on the upper surface, with 4(–5) basal sheaths. Cauline leaves 4–6, lax and irregularly denticulate at the margin, with 4–8 teeth per mm, the lowest little developed, 2–3 median leaves subround to round– ovate, obtuse, 3.2–4.5(–5.0) × 2.0– 3.6 cm, often shorter than internode, subrigid, erect–divaricate to patent, 1–3 upper ones lanceolate, acute, 6.0 × 1.4–1.6(–2.5) cm. Raceme more or less dense, 15–25 cm long, 14–30(–45) flowered; bracts 1–6 cm, lanceolate to linear–lanceolate, mostly longer than flowers, the upper ones often equalling or shorter than flowers. Flowers obliquely pendent. Ovary subclavate, slightly pedunculate, sparsely hairy, 11.0–14.0 × 4.5–4.7 mm, in section circular with 6 prominent ribs. Sepals ovate to ovate–lanceolate, acute at apex, green tinged with purple, 9.5–11.0 × 5.5–6.5 mm, 5–6 veined. Petals ovate, pinkish–green, pink at the margin, 8.0–9.0 × 4.8–5.8 mm, 7–veined. Labellum 8.5–9.0 mm long; hypochile purplish–brown on the bottom and pinkish above and outside, 4.5–5.0 × 5.0– 5.5 mm; epichile cordate, 4.0–4.2 × 5.0–6.0 mm, marginal pinkish–white, pink in the central part, tinged with green at the apex, bent downwards, bosses pink with 9–11 longitudinal plicae. Anther sessile, rounded at apex, leant above the stigma. Clinandrum well developed. Rostellum present. Stigma rectangular, subvertical.

Phenology:— Epipactis hyblaea flowers in May and is in fruit from May to June.

Habitat and distribution: — Epipactis hyblaea occurs at an elevation of ca. 600 m a.s.l., in the Hyblean area (southeastern Sicily). It grows on Miocene marly limestones in the understory of holm oak woodlands, where it is localized in the northern slops of narrow valleys. In this mesic situation, E. hyblaea is a member of sciaphilous community characterized by other orchids, such as Epipactis microphylla and Cephalanthera damasonium ( Miller 1768: n. 2) Druce (1906: 225), as well as several other nemoral species, among them Urtica rupestris Gussone (1821: 15) , Lamium flexuosum Tenore (1820: 19) etc.

IUCN red list category:— Epipactis hyblaea is a rare endemic species currently known only from a limited area within the Pantalica Natural Reserve, Valle dell’Anapo e Torrente Cava Grande, a peculiar location rich in several different types of natural woods as well as other rare and significant habitats characterized by numerous endemics. This species is represented by a small population of ca. 20 individuals and can be considered a relict element of the Hyblaean flora. According to Brullo et al. (2011), the Hyblaean territory is an area important from the biogeographical point of view, mainly due to the high plant diversity that characterises it. In fact, in this area occur many rare endemics, some of them with an old origin, as for instance Urtica rupestris , Zelkova sicula Di Pasquale, Garfì & Quézel (1992: 403 , 406) Trachelium lanceolatum Gussone (1843: 252) , Aristolochia altissima Desfontaines (1799: 324) , Anthemis pignattiorum Guarino, Raimondo & Domina (2013: 821) , Limonium syracusanum Brullo (1980: 284) , L. hyblaeum Brullo (1980: 282) , L. pachynense Brullo (1980: 292) , Helichrysum archimedeum C. Brullo & Brullo (2011: 56) , H. hyblaeum Brullo in Minissale (1995: 630), Ferulago nodosa subsp. rigida Troia & Raimondo in Troia et al. (2012: 336), etc. Based on current knowledge, Epipactis hyblaea should be classified, according to the IUCN criteria (2010), as a critically endangered species: CR D.

Etymology: —The specific epithet refers to the Hyblaean territory where this plant grows.

Taxonomic relationships: —From the taxonomic point of view, Epipactis is one of the most complex and still poorly known genera of Orchidaceae occurring in the Euro–Mediterranean area ( Richards et al. 1982, Ehlers et al. 2002, Squirrell et al. 2002, Bateman et al. 2005, Hollingsworth et al. 2006, Talalaj & Brzosko 2008, Tranchida–Lombardo et al. 2011). In particular, within this genus it is possible to recognized several aggregate species, exhibiting among them significant morphological differences regarding leaves, flower structure and pollination systems. As emphasized by the authors cited above, the outcrossing (allogamous) species are usually characterized by a widespread distribution and show a remarkable variability in the vegetative and reproductive structures, whereas selfing (autogamous) species, represented often by endemics, have a circumscribed distribution and low infraspecific variation (Tranchida–Lombardo et al. 2011). Based on data from the literature ( Rossi & Klein 1987, Bartolo et al. 1996a, 1996b, Baumann & Lorenz 1988, Bongiorni et al. 2007, Hollingsworth et al. 2006, Tranchida–Lombardo et al. 2011, Brullo et al. 2013), active speciation is currently observed within populations belonging to Epipactis helleborine group, occurring mainly in stands located at the margin of the distribution area of this genus, as for instance southern Italy and Sicily.

Epipactis hyblaea has an especially close relationships with E. distans , a species distributed, according to Benito Ayuso et al. (1999) and Müller (2011) mainly in the southern Europe (southwestern Spain, southern France, northern Italy, Switzerland, Austria, Czech Republic, Slovakia, Slovenia and Hungary, with scattered stands in Germany, Croatia, Corsica, Greece, Poland, Sweden and Lithuania). The latter species is recorded in Italy in various localities of the northern territories ( Grünanger 2009), while more recently Lindig & Lindig (2012) have found a small population in northern Calabria on Mt. Pollino, where it grows on limestone limited to sunny places at 1100–1200 m ( Fig. 4 ).

Based on living material and data the literature, E. hyblaea is morphologically well differentiated from E. distans in several features of leaves and flowers, as well as phenology and ecological requirements ( Table 1). In particular, the most relevant features that allow it to be distinguished from E. distans are, in the latter: fewer basal sheaths, larger median cauline leaves, which are erect to suberect and densely denticulate at the margin, smaller hypochile, smaller epichile with evanescent plicae in the protuberances and larger ovary with shorter pedicel; in addition it is later flowering and grows usually in sunny habitat.

For E. distans , there are various conflicting opinions, mainly regarding taxonomic rank and the correct binomial ( Klein 1997, Baumann et al. 2002, Ströhle 2003, Kreutz 2004, Perazza & Decarli Perazza 2005, Delforge 2004, 2006). In order to clarify the nomenclature state of Epipactis distans , the following is provided:

Figures

FIGURE 4. Geographical distribution of Epipactis distans (A) and E. hyblaea (B), by Müller (2011), modified.