CEPHALANTHERA EPIPACTOIDES (ORCHIDACEAE) IN RUSSIA

Twenty species of the orchid genus Cephalanthera are known in the World and seven species occur in Russia. One of them, restricted in Russia to the Black Sea coastal area of the Krasnodarsky Krai in the �orth �au� casus, has a long story of misidentifications and taxonomic confusions. The present study revealed that the correct name for this species is Cephalanthera epipactoides while it was previously known in Russia as either C. cucullata or C. kurdica (= C. floribunda). The lectotype of C. epipactoides is designated. Morphological description of the species is provided with measurements of the main parameters. The distribution of C. epipactoides in Russia is summarised on the base of herbarium specimens, data from the «Plantarium» website, field observations, and previously published records; the species is known here along approximately 125 km from the environs of Anapa to Dzhubga. The Russian part of the species range is isolated from its main area of distribution; the nearest locality in Turkey is about 365 km away from Dzhubga (linear distance). The popula� tion quantity of the species in Russia is very low. Cephalanthera epipactoides is highly threatened in Russia; its conservation status is «critically endangered». Further study of the species is recommended, in particular, in relation to its pollination ecology.


Introduction
With ca. 28 000 described species, the orchid family (Orchidaceae) is the second largest plant family in the World after Asteraceae (�hristenhusz & Byng, 2016). At the same time, orchids are also the most threatened plants due to their complex life history strategies, charisma, and threats from overcollection and habitat loss (Pillon & �hase, 2006;Fay & Chase, 2009;Fay, 2018). Many species of orchids are going to be extinct, first of all, due to destruction of their habitats and climate change (Swarts & Dixon, 2009;Efimov, 2012). Taxonomic complexities, which affect the most appropriate delimitation of species, cause problems for their conservation (Flanagan et al., 2006;Hollingsworth et al., 2006;Cameron, 2010;Vereecken et al., 2010). Some groups of orchids are still poorly known, especially in tropical regions. Taxonomic studies of these plants, however, are continued even in temperate Eurasia. Most of them are dedicated to the complex genera Epipactis Zinn, Dactylorhiza �eck. ex Nevski, and Ophrys L. (Efimov et al., 2016;Jakubska-Busse et al., 2017;Bateman & Rudall, 2018;Fateryga et al., 2018a,b;Zhou & Jin, 2018;Baguette et al., 2019). Other genera, which are relatively better known, however, are also studied (e.g., Bateman et al., 2017).
The Holarctic and Oriental genus Cephalanthera Rich. (Orchidaceae: Epidendroideae: Neottieae) contains 20 species. One of them is known from North America, five from the East Mediterranean to the �aucasus, three have a broad distribution in temperate Eurasia and a small area in North Africa, and 11 species are distributed in East and Southeast Asia (Govaerts et al., 2005(Govaerts et al., -2020. Seven species are known from Russia. Among them, there are three broadly distributed taxa: Cephalanthera damasonium (Mill.) Druce, C. longifolia (L.) R.M. Fritsch, and C. rubra (L.) Rich. They are relatively common in the European part of Russia, including the �rimea and the �orth �aucasus (Averyanov, 2006;Red Data Book of the Russian Federation, 2008;Vakhrameeva et al., 2008;Fateryga et al., 2019;Ivanov, 2019). Two other species, Cephalanthera erecta (Thunb.) Blume and C. longibracteata Blume, are restricted to the Far East: Primorsky Krai, Sakhalin, and Kuril Islands (Red Data Book of the Russian Federation, 2008; Vakhrameeva et al., 2008). The sixth species, Cephalanthera caucasica Kraenzl., is reported only from the Samur River delta, the southernmost locality of the Republic of Dagestan in the �orth Caucasus (Averyanov, 2006;Ivanov, 2019). These taxa are not problematic, although, the presence of the latter species in Russia has not been confirmed by any recent evidences.
The seventh species of Cephalanthera, restricted in Russia to the Black Sea coastal area of the Krasnodarsky Krai in the �orth �aucasus, has a long story of misidentifications and taxonomic confusions. It was firstly reported by Lipsky (1899) from «Novorossiysk-Anapa» as Cephalanthera cucullata Boiss. & Heldr. Then, C. cucullata was again reported from �ovorossiysk by Fomin & Woronow (1909). In the same paper, they reported another taxon, Cephalanthera floribunda Woronow, but from the Artvin Province (currently Turkey). Grossheim (1928) again reported C. cucullata, but with C. floribunda as its synonym, from both territories. Actually, C. cucullata is a species endemic to the Island Crete while C. floribunda is a synonym of Cephalanthera kurdica Bornm. ex Kraenzl. distributed in Armenia, Azerbaijan, Turkey, Syria, Lebanon, Iraq, and Iran (Kreutz, 1998(Kreutz, , 2004Govaerts et al., 2005Govaerts et al., -2020Vakhrameeva et al., 2008;Delforge, 2016). Then, the species occurring in Russia was reported in the Flora of USSR as Cephalanthera epipactoides Fisch. & �.A. Mey. with both C. kurdica and C. floribunda as its synonyms (Nevski, 1935). According to the modern data, C. epipactoides is known from Greece, Bulgaria, and Turkey; C. kurdica is not currently treated as its synonym (Kreutz, 1998;Govaerts et al., 2005Govaerts et al., -2020Assyov et al., 2012;Delforge, 2016). After that, Grossheim (1940) also reported C. epipactoides, with C. floribunda as its synonym, from the Russian Black Sea coastal area and Armenia. Then, Czerepanov (1995) listed two species occurring in the �aucasus: C. floribunda and C. kurdica. After his paper, the first name became commonly used for the species occurring in Russia and Azerbaijan while the second one was used for the Armenian plants (Perebora, 2002(Perebora, , 2011Dubovic, 2005;Ivanov & Kovaleva, 2005;Vakhrameeva, 2008;Vakhrameeva et al., 2008). Averyanov (2006), however, reported C. kurdica, with C. floribunda as its synonym, for the whole Caucasus and his opinion was followed by Ivanov (2019). At the same time, Zernov (2006) used the name C. cucullata for the Russian plants and his opinion was accepted in the Red Data Book of Krasnodarsky Krai (Zernov & Popovich, 2017).
All taxa of the genus Cephalanthera mentioned above (C. cucullata, C. epipactoides, and C. kurdica = C. floribunda) belong to a monophylectic group (section Cucullatae Zernov) which is characterised by the presence of a spur at the base of the hypochile (Delforge, 2016). The second character of this group is short leaves, which are approximately equal in length to the corresponding internodes. These three species differ from each other mainly by flower size (smaller in C. cucullata and larger in C. epipactoides and C. kurdica) and coloration (bright pink in C. kurdica and white to yellowish or cream in C. cucullata and C. epipactoides). They are allopatri� cally distributed (Kreutz, 1998;Delforge, 2016). In contrast to the abovementioned Russian literature, these plants are usually not reported from Russia by foreign scientists. �one of the three species were reported from this country by Delforge (2016) and even the «World �hecklist of Selected Plant Fami� lies» (Govaerts et al., 2005(Govaerts et al., -2020 added Russia to the distribution of C. kurdica only in 2018. Bau� mann & Künkele (1982), however, added a small area of the Russian Black Sea coast to the distribu� tional map of C. epipactoides but this information was ignored by further research.
The purpose of the present study is to ascer� tain what species of Cephalanthera of the section Cucullatae actually occurs in Russia (C. cucullata, C. epipactoides, or C. kurdica) and summarise the data on its distribution within this country.

Material and Methods
Field observations were carried out in the Krasnodarsky Krai (Russia) in 2019. Plants were observed at three localities: 1) the vicinity of Kamchatka khutor, �ovorossiysk urban okrug (44.711389°N, 37.626389°E) on 10.05.2019; 2) outskirts of Dzhubga, Tuapse district (44.319722°N, 38.708333°E) on 11.05.2019; 3) outskirts of Myskhako, Novorossiysk urban okrug (44.665834°N, 37.752491°E) on 15.05.2019. The first locality was an oak forest with predomination of Quercus pubescens Willd. and Carpinus orientalis Mill. The second locality was an edge of an artificial pine forest. Pinus nigra subsp. pallasiana (Lamb.) Holmboe was the main species of trees while some native species, such as Q. pubescens, were also present there (Fig. 1A). The third locality was a sparse forest with Q. pubescens, C. orientalis, and some individuals of Juniperus deltoides R.P. Adams, and Cotinus coggygria Scop. Ten plants were randomly selected in both the first and the second locality; four additional plants were studied in the third locality (there were no more plants there). Each of these plants was measured with a metal tape measure. The measured parameters were the shoot and the inflorescence lengths as well as the length and the width of the largest leaf. Numbers of leaves and flowers were also calculated. After that, the lowest flower of the plant was cut and its straightened parts were placed between a paper and a piece of a transparent adhesive tape. These flowers were then measured in the laboratory with a vernier caliper. The measured parameters were the length of the ovary, lengths and widths of sepals and petals, the length of the lip, the width of the epichile, and the length of the column. Then, the minimum, the maximum, and the mean values were calculated for each parameter. Confidence intervals of the mean values were calculated for 95% confidence level (p = 0.05).
The distribution of the species in Russia was ascer� tained using the data from several herbaria (KW, L, LE, MHA, PHEO, and YALT), as well as the digital version of the Herbarium MW (Seregin, 2020). The data from the «Plantarium» website (Plantarium, 2007(Plantarium, -2020, field observation made by the authors, and published records (Zernov & Popovich, 2017) were also used. Type material was studied in the digital version of the Herbarium P (MNHN, 2020).

Results and Discussion
All studied plants of the Cephalanthera section Cucullatae, i.e., the plants with a spur at the base of the hypochile collected in the Krasnodarsky Krai of Russia, were identified as C. epipactoides. They had sepals up to 26 mm long and a spur up to 4 mm long while C. cucullata has sepals less than 20 mm long and a spur 1-2 mm long (Moore, 1980;Delforge, 2016). All plants also had pure white to yellowishwhite coloration of flowers while C. kurdica has pink perianth at least in most specimens (Renz & Taubenheim, 1984;Kreutz, 1998;Delforge, 2016 (Fig. 2).

Remarks
Von Fischer & Meyer (1854) described C. epipactoides on the base of the material collected in Turkey by P. de Tchihatcheff in 1849. Four specimens of this species, collected by this person, are preserved in the herbarium of the Museum National d'Histoire �aturelle in Paris, France (P). Two of them, mounted together under the number P00345202, were collected between Sarnychky (currently Sagalossos) and Ağlassan at the foot of the Taurus Mountains (Pisidia), i.e., at a different location than was specified in the protologue. Two remaining specimens are also mounted together but have different numbers. Both were collected in Asia Minor but further details were not specified. Thus, they do not contradict to the protologue. Among them, P00345204 has better condition than P00345203. Therefore, the former specimen is designated as the lectotype.

Distribution
Russia (Krasnodarsky Krai), Greece, Bulgaria, Turkey (Kreutz, 1998;Govaerts et al., 2005Govaerts et al., -2020Assyov et al., 2012;Delforge, 2016). In Turkey, where both C. epipactoides and C. kurdica are known, C. epipactoides is distributed over the northwest part of the country while C. kurdica occupies the southeast (Kreutz, 1998). In Russia, the species is restricted to the Black Sea coastal area of the �orth �aucasus where it is distributed from the environs of Anapa to Dzhubga (Fig. 3). The easternmost locality shown on the map (Shaumyanskiy Pass) is doubtful due to its isolated position; it was listed in the Red Data Book of Krasnodarsky Krai (Zernov & Popovich, 2017) with the reference to Perebora (2011). The presence of C. epipactoides in this place requires further confirmation. There is also one locality listed in the Red Data Book of Krasnodarsky Krai (Zernov & Popovich, 2017) but not shown on the present map (Fig. 3). This is the vicinity of �atukhayevskaya (Novorossiysk urban okrug); Zernov & Popovich (2017) reported this place, while listing the distribution of «C. cucullata», with reference to the Herbarium KW. Actually, there are two series of C. damasonium, collected in �atukhayevskaya and erroneously identified as C. epipactoides, in KW. The first one (seven sheets) was collected on 25.05.1958 by M. Kotov and the second one (five sheets) was collected on 25.06.1959 by M. Kotov, V. Protopopova, and V. Strashko. The latter series also has a duplicate in LE (LE01038193!). As far as there are no correctly identified C. epipactoides from the vicinity of �atukhayevskaya in KW, its record from this place by Zernov & Popovich (2017) was obviously erroneous.

Pollination
There are no published data on pollinators of C. epipactoides (�laessens & Kleynen, 2011). Experiments revealed that the pollinia can be re� moved from the flowers with a needle, i.e., the species is probably cross-pollinating. However, no flowers with the pollinia removed by insects were found during the observations. It can be supposed, that the pollinators are solitary bees and the pollination strategy is a food deceptive mechanism, which is known in C. longifolia and C. rubra (�laessens & Kleynen, 2011).

Conservation status
The species was included to the Red Data Book of the Russian Federation (Vakhrameeva, 2008) under the name C. floribunda with the sta� tus «2» (decreasing in number = endangered) and to the Red Data Book of Krasnodarsky Krai (Zernov & Popovich, 2017) under the name C. cucullata with the status «1» (critically en� dangered). Cephalanthera epipactoides is really critically endangered in Russia. The total num� ber of individuals of this species growing in the Krasnodarsky Krai was estimated as not more than 1000 (Zernov & Popovich, 2017). The spe� cies must be included into the next edition of the Red Data Book of the Russian Federation under the correct name (C. epipactoides) and with the actual status (critically endangered).

Conclusions
Cephalanthera epipactoides is the correct name for the species which was previously known in Russia as either C. cucullata or C. kurdica (= C. floribunda). The area of its distribution in Russia is isolated from the main part of the spe� cies range; the nearest locality in Turkey is near Perşembe, Ordu Province (Kreutz, 1998), which is about 365 km away from Dzhubga (linear dis� tance across the Black Sea). In Russia, C. epipactoides has a low population quantity and limited distribution on the Black Sea coastal area of the North Caucasus (along approximately 125 km). The species is highly threatened and requires fur� ther studies (e.g., on the pollination ecology).