Epipactis euxina Fateryga, Popovich & Kreutz, 2018

Fateryga, Alexander V., Popovich, Anton V., Fateryga, Valentina V. & Averyanova, Elena A., 2018, New data on the genus Epipactis (Orchidaceae) in the North Caucasus with description of a new species, Phytotaxa 358 (3), pp. 278-288 : 279

Epipactis euxina Fateryga, Popovich & Kreutz , sp. nov. ( Figs 1–2 )

Differs from Epipactis persica by its pedicel ± equal in length to ovary versus several times shorter than ovary, epichile much longer than wide versus ± equal in length and width, viscidium indistinct or absent versus distinctly present.

Type: — RUSSIA. Krasnodar Territory: Gelendzhik District, vicinity of khutor Dhzankhot , Mt Svyataya Nina , 44°27′37″N, 38°10′02″E, ca. 300 m, burnt pine forest, 10 June 2017, Fateryga, Fateryga & Popovich s.n. (holotype LE 01040770 !; isotype LE 01040769 !) .

Rhizomatous perennial herbs. Plant 25–45 cm tall, with 1–2 stems. Stem erect or slightly inclined, yellowish-green, sparsely pubescent with minute hairs, with 3–7 spirally arranged leaves. Leaves yellowish-green, ± arching, some shorter to two times longer than the internodes; lower one orbiculate to ovate, 10–25 × 10–20 mm, the medium ones ovate to lanceolate, 35–75 × 15–25 mm; the upper ones lanceolate to elongate, 40–55 × 5–10 mm. Inflorescence loose, relatively short, 6–12 cm long, with 5–20 flowers. Bracts narrow, lanceolate to elongate, acute, exceeding the flowers, diminishing in length higher up; the lower ones 28–36 × 4–6 mm, the medium ones 20–22 × 2–3 mm, the upper ones 10–12× 1 mm. Pedicel fawnish-green, 6–10 mm long. Ovaries green, sparsely pubescent with minute hairs as well as the stem, 6–10 × 2–4 mm. Perianth campanulate, sepals 6–10 × 3–5 mm, yellowish-green, petals 6–9 × 3–5 mm, not different in color from the sepals. Hypochile cup-shaped, 3.5–4.0 × 3.0– 3.5 mm, greenish-pink outside and reddishbrown inside, containing liquid; junction of hypochile and epichile narrow; epichile cordate, 4.0–4.5 × 3.0– 3.5 mm, yellowish-green, with two distinct ± smooth pink bosses. Viscidium indistinct or absent, pollinia friable, flowers self-pollinating.

Etymology: —The specific epithet “ euxina ” refers to Εὔξεινος Πόντος (“Pontus Euxinus” in Latin), an Ancient Greek name for the Black Sea, on the shore of which the type locality is situated.

Distribution: —The species is currently known only from its type locality.

Habitat, elevation, and phenology: —Sparse pine forest mixed with oak, on calcareous soils, ca. 300 m. Flowering season is June.

Note: —The new species belongs to Epipactis phyllanthes group sensu Delforge (2016) due to its weakly pubescent stem and ovaries. It is quite closely related to another easternmost species of this group, E. persica , from which it differs by its remarkable long pedicel, distinctly longer epichile, and indistinct or absent viscidium. From the other hand, E. euxina has some characters similar to E. leptochila ( Godfery 1919: 38) Godfery (1921b: 146– 147) subsp. leptochila , namely by its epichile, which is longer than wide, and by its viscidium which is indistinct or absent. However, the newly described species strongly differs from E. leptochila s.l. by its weakly pubescent stem and remarkably long pedicel. A comparison of the main diagnostic characters of E. euxina with those of the related taxa is present in the Table 1. The table also includes E. exilis Delforge (2004: 246) , which is often treated as the subspecies of E. persica , and Western Mediterranean E. fageticola (Hermosilla in Hermosilla & Sabando 1998: 138) Devillers-Terschuren & Devillers in Devillers & Devillers-Terschuren (1999: 302), which is quite similar to E. euxina in its habit.

Figures

FIGURE 1. Type of Epipactis euxina (LE 01040770).

FIGURE 2. Epipactis euxina in its type locality in Krasnodar Territory (Gelendzhik District, vicinity of khutor Dhzankhot, Mt Svyataya Nina). A. Habit of plants in bud. B–C. Flowering plants. D. Lower part of inflorescence. E. Flower, laterally. F–H. Flowers, frontally. Photos by A.V. Fateryga (A, C, E–H) and V.V. Fateryga (B, D).