In her monograph on Siberian species, Peschkova (1994) accepted 30 species and two subspecies and provided distribution maps of all taxa. Her study is used as a reference for treating the geographical area that is dealt with here. However, as her geographical area also included Arctic parts of Siberia, five species and two subspecies from the Arctic are instead treated in group C below, together with other Asian Arctic species. Peschkova (1994) did not treat species from the Russian Far East, which is also in a geographical area different from the one dealt with here. Mongolia, the Central Asian republics and northern China, which belong to the present geographical area, were also outside the scope of her treatment. A recent flora checklist from Mongolia (Baasanmunkh et al. 2022) follows the species concepts of Peschkova (1994), except for two accepted species not present in Siberia: Papaver baitagense Kamelin & Gubanov and P. pseudotenellum Grubov. However, Baasanmunkh et al. (2021) considered these species as synonyms of or very closely related to P. croceum Ledeb. and they are therefore synonymised below.

For a long time, the only species recognised from this area were P. nudicaule L. and P. croceum Ledeb. In addition, there were several taxa at infraspecific rank, two of which have intricate histories, which will be dealt with below. Papaver nudicaule var. rubro-aurantiacum Fisch. ex DC., was introduced by De Candolle (1821), although it has been treated as if it were a nomen nudum by several later authors. De Candolle (1821) had referred to a collection from Dahuria sent by Fischer, who apparently had suggested the name “in litt.”. However, later in his treatment, below a comparison of his three varieties of P. nudicaule, De Candolle (1821) presented a short diagnosis for var. rubro-aurantiacum, for which he wrote that it might represent a true new species. His name for this taxon is, therefore, accepted as a basionym here.

Peschkova (1994) cited the taxon as P. rubro-aurantiacum Fisch. ex R. Sweet. However, Sweet (1830) only listed the name at the species level in a horticultural magazine without any attempt at a taxonomic treatment, without citing the treatment by De Candolle (1821) and Sweet’s citation to the year “1822” instead refers to its introduction into British gardens. However, Hassler (2023b) cited the taxon as P. rubro-aurantiacum Fisch. ex Steud. Steudel (1841) only included the name in an enumeration where it was interpreted as a synonym of P. croceum. Fedde (1909) recombined the taxon as a subspecies. Lundström (1923) studied the holotype material collected in Dahuria by Fischer and sent to De Candolle, recombined the taxon at the species level and provided an extended description. His author citation deviates from the citation format followed by us, namely P. rubroaurantiacum (Fisch. ex DC.) C.E.Lundstr. The hyphen inserted by Lundström is deleted according to the Code (Article 60.11; Turland et al. (2018)). The name citation applied here is also in accordance with the treatment by POWO (2023). The type material was not explicitly cited by Lundström (1923), is not deposited at BG as indicated by Popov (1937) and Rändel (1974) and its herbarium affiliation is unknown to us.

Peschkova (1994) considered P. rubroaurantiacum to be heterogeneous, also including P. ledebourianum C.E.Lundstr., but mapped it as very common in southern Siberia, largely overlapping with the distribution area of P. nudicaule, but stated that they differ in flower colour and pubescence of sepals and capsules. Zhang and Grey-Wilson (2008), however, treated P. rubroaurantiacum as a synonym of P. nudicaule. Kamelin and Gubanov (1990) described P. changaicum Kamelin from Mongolia, differing from P. rubroaurantiacum by white flowers and it is treated as a synonym of the latter here. They also described P. rubroaurantiacum subsp. chalchorum Kamelin from calcareous steppes in Mongolia, but this taxon was not accepted by Baasanmunkh et al. (2022).

Another early described taxon is Papaver leiocarpum (Turcz.) Popov, with its basionym Papaver nudicaule var. leiocarpum Turcz., published in 1838. IPNI (2023) cites the basionym as P. leiocarpum Turcz., referring to the same publication source, which agrees with the citation in Popov (1937). However, the original publication only lists “P. lejocarpon m.” which is a nomen nudum as it lacks an accompanying description. The significance of the added “m.” is unknown and possibly refers to a manuscript. Therefore, it appears that the publication source of the basionym cited by Peschkova (1994) as “1842–1845, Fl. Baic.-Dahur. 1: 98” instead represents its description. Krivenko (2023) cited the nomen nudum from 1838 instead of the basionym published by Peschkova (1994). However, the Code (Art. 41.6; Turland et al. (2018)) allows for erroneous basionym citations. Thus, the name Oreomecon leiocarpa (Turcz.) Krivenko is considered validly published, with the correct basionym citation supplied here.

In his treatment of Papaver for Flora SSSR, Popov (1937) included two Central Asian species of sect. Meconella described by Tolmachev (1931), as well as his own descriptions of five new species. Two of these, Papaver pseudostubendorfii Popov and P. ajanense Popov, were both synonymised with P. stubendorfii Tolm. by Peschkova (1994), whereas P. pseudocanescens Popov was accepted, while P. involucratum Popov was outside her study area. Papaver tianschanicum Pavlov was introduced as a nomen nudum in 1933. When described by Popov a year later, the name P. tianschanicum Popov would have been more appropriately cited as “Papaver tianschanicum Pavlov ex Popov”, as done by Hassler (2023b). However, as this is only an alternative in the Code (Art. 46.5; Turland et al. (2018)), this correction is not followed here. The species was re-described by Popov (1937) as an isonym and was accepted by Peschkova (1994). It was synonymised with P. canescens Tolm. by Zhang and Grey-Wilson (2008), but accepted by Galasso et al. (2023).

Papaver amurense (N.Busch) N.Busch ex Tolm. was accepted by Peschkova (1994). In contrast, Zhang and Grey-Wilson (2008) treated it as P. nudicaule f. amurense (N.Busch) H.Chuang. POWO (2023) and Hassler (2023b) cited the species as P. amurense (N.Busch) Karrer, based on Karrer (1935). However, the latter is a short and non-taxonomical notice in a horticultural magazine, without even an indirect reference to a basionym as required prior to 1953 by the Code (Art. 41.3; Turland et al. (2018)) and this is not a valid recombination. Tolmachev (1971) dealt specifically with this species, but did not cite its type.

A taxon known as Papaver tenellum Tolm. was accepted by both Popov (1937) and Czerepanov (1995) and also by Peschkova (1994), although her statement that it “evidently represents a shade form of P. pseudocanescens” leads us to reject this species. Tolmachev (1930) treated it as P. tenellum (Korsh.) Tolm., based on a name “in sched.” by Korshinsky at LE. Its author citation is, therefore, given as ‘Korsh. ex Tolm.’ and the Korshinsky specimen illustrated by Tolmachev (1930) is designated as lectotype here. Papaver tenellum was considered a synonym of P. nudicaule by Zhang & Grey-Wilson (2008) but accepted by Solstad et al. (2009) and POWO (2023). Following the argument by Peschkova (1994), Oreomecon tenella (Tolm.) Krivenko is listed below as a synonym of Papaver pseudocanescens Popov.

Papaver rubroaurantiacum subsp. longiscapum Rändel was recombined into species level by Krivenko (2023). However, the taxon was considered “simply the full-grown forms of P. rubro-aurantiacum” by Peschkova (1994) and her opinion is followed here. With the exceptions noticed above, we accept all species treated by Peschkova (1994), i.e. 23 species in total, of which six were described as new to science by her. The list also includes four species recombined by Peschkova (1994).

The diploid species Papaver kuvajevii Schaulo & Sonnikova (Shaulo and Sonnikova 2003) was described from a single locality in Krasnoyarsk Krai in Khakassia, Russia and is included in the list below. Only two more species have been described from the area south of Peschkova’s study area. The endemic Papaver involucratum Popov from 2800–3300 m alt. in the western Pamir-Alay mountains in Tajikistan has been accepted by most later authorities and is also included in the list below. It has also been collected from the Afghan side of the border as shown by GBIF (Global Biodiversity Information Facility) Secretariat (2023). Papaver angrenicum Pazij from the western Tian Shan mountains in Uzbekistan was accepted by Rändel (1974), based on several morphological characters. It has been treated as a synonym of P. croceum in flora lists by Czerepanov (1995) and Sennikov and Tojibaev (2021). The latter interpretation is followed here, although a re-study vs. neighbouring species is needed to finally reject the conclusion by Rändel (1974). Papaver involucratum subsp. nigrescentihirsutum Tolm. was accepted by Solstad et al. (2009), but not by POWO (2023) nor by us. The report by Jafri and Qaiser (2011) of Oreomecon nudicaulis s.lat. from Pakistan probably refers to O. crocea in the sense of Peschkova (1994) and Sennikov and Tojibaev (2021). Notably, Oreomecon has not migrated westwards into the high mountains of Iran, Caucasus and Türkiye.

Fig. 2 shows the distribution of the genus Oreomecon in this geographical area, which is considered to include 24 species. Papaver croceum was shown by Peschkova (1994) to have a south-western Siberian distribution pattern that does not overlap with the south-eastern one of P. nudicaule. Papaver amurense overlaps with P. nudicaule in south-eastern Siberia, but extends into the Russian Far East and southeastwards into China (Peschkova 1994). It also occurs in North Korea (Chang et al. 2014). Papaver pseudocanescens Popov and P. rubroaurantiacum were mapped as particularly widespread and abundant by Peschkova (1994).

Papaver turczaninovii is an endemic with a limited distribution south-east of Lake Baikal, while P. kuvajevii is only known from the two localities in East Sajan, as reported by Shaulo and Sonnikova (2003). An’kova et al. (2018) also briefly listed it from China, but no localities or samples were reported. In GBIF (Global Biodiversity Information Facility) Secretariat (2023), only the two localities by Shaulo and Sonnikova (2003) are available. The endemic Papaver olchonense and P. popovii were only mapped from the Lake Baikal area by Peschkova (1994), although with quite many localities and with a single locality of P. olchonense in the Republic of Sakha ca. 1,300 km north of the northern edge of Lake Baikal. Papaver popovii was cited as rare and endangered along Lake Baikal shorelines by Bukharova et al. (2021). A new locality of this species was recently recorded from Agara River, ca. 500 km west of the northern edge of Lake Baikal as shown by GBIF (Global Biodiversity Information Facility) Secretariat (2023). Papaver involucratum was described as endemic and occurring in several areas of the western Pamir-Alai mountains in Tadzhikistan (Popov 1937). Papaver turczaninovii was treated as a stenotopic endemic by Peschkova (1994), being restricted to outcrops of marble limestones at the southeastern shore of Lake Baikal. Eight of the species were listed as Nearly Threatened (NT) in Russia by Xue et al. (2023), with only P. tenellum (included in P. rubroaurantiacum above) listed as Vulnerable (VU).

This area is defined as comprising north-eastern China (Liaoning, Jilin, Heilongjiang), the Korean Peninsula, Japan and non-Arctic areas of the Russian Far East, the latter defined as the eight easternmost administrative units in Russia. This area does not overlap geographically with the administrative units comprising Siberia, as dealt with by Peschkova (1994). The Papaver flora of the former Soviet Far East was presented by Bezdeleva (1987) and later updated for the Russian Far East by Bezdeleva et al. (2006). These two studies are used here as a combined reference study for this geographical area.

Altogether, these studies included 34 species, 30 of them presented with distribution maps, although the majority of the species are from the Arctic parts. In the present treatment, the latter are included in the next geographic group, except for three species with most of their occurrences on the American side. Therefore, they are treated in the group of Arctic Alaskan and Yukon species. Only a few of the Siberian species treated by Peschkova (1994) have marginal occurrences within the presently-defined area. To conclude, seven species dealt with by Bezdeleva (1987) and Bezdeleva et al. (2006) are exclusive to the presently-defined geographical area and are commented on below.

The earliest name from the area is Papaver microcarpum DC. described from Kamchatka by De Candolle (1821), based on a P.S. Pallas collection, although the true collector was possibly C.H. Merk in 1788, who passed his plant collections over to Pallas (Yakubov et al. 2001). Tolmachev (1931) described Papaver ochotense Tolm., but later, Tolmachev (1975) recombined it as one of four subspecies of P. microcarpum, another one being P. microcarpum subsp. alaskanum (Hultén) Tolm. In his distribution map, Papaver microcarpum subsp. ochotense (Tolm.) Tolm. was shown to have a distinct southern distribution compared to P. microcarpum subsp. microcarpum with an Arctic distribution in Chukotka and P. microcarpum subsp. czekanowskii (Tolm.) Tolm., both occurring from Chukotka to much further to the west in Arctic Yakutia. These distribution patterns were confirmed by Petrovsky (1999).

These studies dealt with the Arctic and, for the Far East, Bezdeleva (1987) mapped Papaver microcarpum southwards to the Magadan area and southernmost parts of Kamchatka as a widely defined species without accepted subspecies, a concept also followed by Bezdeleva et al. (2006). Grey-Wilson (2023) did not even accept P. macrocarpum as a separate species, but recombined it as a subspecies of Oreomecon nudicaulis. Czerepanov (1995) and Pavlova (1999) accepted Papaver ochotense Tolm. as a separate species, whereas Krivenko (2023) did not recognise this taxon, but recombined Papaver czekanowskii Tolm. at the species level in Oreomecon.

Elven et al. (2011) treated the complex as three subspecies, but added that “it may consist of three (or more) separate species” and cited unpublished studies where P. czekanowskii and P. microcarpum s.str. were surprisingly different genetically. They also mentioned Papaver omolonense Khokr., supposedly described from the Magadan area, a name we could not find in any of the cited sources. Solstad et al. (2009) also reported on a genetically distinct taxon from Karaginsky Island off northern Kamchatka referred to as “P. sp. aff. microcarpum”. It is tetraploid, whereas microcarpum is diploid. Following the hypothesis by Elven et al. (2011) and the evolutionary pattern within the genus in the Asian Far East, the three taxa are treated as separate species within Oreomecon here, with O. microcarpa (DC.) Krivenko as primarily a non-Arctic species. Chukotkan specimens of P. microcarpum subsp. microcarpum are left for interpretation by future studies.

Another early name from the area is Papaver anomalum Fedde (Fedde 1909). It was accepted by Popov (1937), who lumped it with P. nudicaule subsp. amurense N.Busch., a conclusion which V. Komarov (1937), the Editor of “Flora SSSR”, opposed. Rändel (1974) agreed that P. anomalum sensu Fedde is different from P. amurense. However, she treated it as a subspecies of P. croceum. Bezdeleva (1987) provided a key separating this species from its most closely-related species, P. amurense and mapped the latter as very common in the southern part of the Far East, particularly near the Chinese border, whereas P. anomalum is much rarer. Peschkova (1994) and Zhang & Grey-Wilson (2008) omitted P. anomalum from their studies, but Peschkova (1994) treated P. anomalum var. hispidissimum (Ledeb.) Tolm. as a synonym of the Siberian P. setosum (Tolm.) Peschkova. Papaver anomalum was recombined into Oreomecon by Banfi et al. (2022) and POWO (2023) and Hassler (2023b) accepted this name. As emphasised by Fedde (1909), the species is very distinct by its almost globose, mostly glabrous capsules and the name is lectotypified here, based on a specimen in B where both capsule and flowers are developed. This sheet would have been readily available to Fedde and apparently carries his handwriting.

Papaver alboroseum Hultén was not typified by Hultén (1928) and, as shown by Björk (2019), two duplicates of the type exist. Here, we designate the collection at S as lectotype, as capsules are much better developed than on the alternative sheet at GB. The latter is defined as isolectotype here, related to its previous and unpublished annotation as “isotype”. According to Yakubov et al. (2001), P. alboroseum and P. microcarpum co-occur on the Avachinsky Volcano in Kamchatka, where both species are frequent.

Pavlova (1999) described P. tolmatschevianum N.S.Pavlova from Sakhalin. This species had already been described and illustrated in Flora of Sakhalin by Sugawara (1937–1940) under the name Papaver ochotense Miyabe & Tatew., which is an illegitimate homonym of P. ochotense Tolm., described by Tolmachev (1931).

Krivenko (2023) recombined Papaver anomalum var. hirsutum Tolm. as Oreomecon hirsuta (Tolm.) Krivenko without making any reference to the synonym Papaver sokolovskajae Prob., which apparently has priority at the species level. Probatova in Bezdeleva et al. (2006) described P. sokolovskajae as a white-flowered species from supralittoral habitats along the coast near Vladivostok. It has conspicuously glabrous and subglobose capsules, a character also noted by Krivenko (2023). However, P. sokolovskajae was not described as a new species, but as a nom. nov. and stat. nov. with Papaver anomalum var. hirsutum Tolm. described by Tolmachev (1971) as the basionym. Probatova did not give any arguments for introducing a replacement name and we cannot find any existing and competing “Papaver hirsutum” name justifying the choice. Based on the Code (Art. 6.10–11; Turland et al. (2018)), we therefore consider P. sokolovskajae as an illegitimate name and instead follow the recombination made by Krivenko (2023).

For the “Flora of China”, Zhang and Grey-Wilson (2008) listed Papaver radicatum var. pseudoradicatum (Kitag.) Kitag. from above 1,600 m alt. on Changbai Shan in the Province of Jilin close to North Korea, also listing the taxon from Korea. Bezdeleva et al. (2006) mapped a single locality of P. pseudoradicatum Kitag. from the Russian side and POWO (2023) indicated this taxon to occur in Korea, “Manchuria” and the “administrative region of Khabarovsk” in the Russian Far East. Chang et al. (2014) also included P. pseudoradicatum from North Korea in their list of species from Korea.

Lee et al. (2011) reported P. coreanum Nakai to be “widely distributed in an alpine belt of Baekdu/Changbaek”, a mountain chain shared by North Korea and China, also referred to as Paektu-san in Korea and Changbai Shan in China. They also cited the species to be protected in China, although the species name applied was not indicated. Zhang and Grey-Wilson (2008) and Chang et al. (2014) did not mention P. coreanum, whereas POWO (2023) listed both P. coreanum and P. pseudoradicatum. The Flora of Korea (Kim 2017) accepted P. coreanum, but did not mention P. pseudoradicatum. Due to their identical distributions in North Korea and the adjacent parts of China and their highly similar morphological descriptions, it is possible that these reports refer to the same species. In that case, P. coreanum, described in 1928, would have priority over P. pseudoradicatum, described in 1942. Krivenko (2023) accepted both these species and recombined them in Oreomecon. We accept P. coreanum and provisionally place P. pseudoradicatum in synonymy pending future studies, but have not been able to cite their types.

A species from the Kurile Islands known as P. miyabeanum Tatew. is closely related to P. fauriei (Fedde) Fedde ex Miyabe & Tatew., a local endemic from Rishiri, a volcanic island just west of the northernmost tip of Hokkaido in Japan (Takahashi and Yamagishi 2020). The former was recombined into Oreomecon by Banfi et al. (2022), citing a basionym originating from Miyabe and Tatewaki (1936). However, the year before, Miyabe and Tatewaki (1935) had described Papaver nudicaule subsp. xanthopetalum var. shimshirense Miyabe & Tatewaki listing the new name P. miyabeanum Tatewaki as a synonym “in sched.”. Takahashi and Yamagishi (2020) restudied the complex and reduced the former to a subspecies of P. fauriei under the name P. fauriei subsp. shimshirense (Miyabe & Tatew.) Hideki Takah. They concluded that the simultaneous publication of P. miyabeanum as a synonym of Papaver nudicaule subsp. xanthopetalum var. shimshirense by Miyabe and Tatewaki (1935) made the former name illegitimate, also when Miyabe and Tatewaki (1936) intended to name the taxon at the species level and when the taxon was recombined as Oreomecon miyabeana (Art. 6.4 and 58.1 in the Code; Turland et al. (2018)). Papaver fauriei was originally published as Papaver nudicaule subsp. xanthopetalum var. fauriei Fedde by Fedde (1909), who defined the specimen Faurie 3015 at B as the holotype, which, according to Takahashi and Yamagishi (2020), has not been relocated and only isotypes are therefore listed below.

We conclude that this area includes nine species and one subspecies. The distribution of the genus Oreomecon in this area is shown in Fig. 2.

Yamagishi et al. (2010, 2018) reported a small population of P. fauriei subsp. fauriei to be Endangered (EN) due to the threat of hybridisation with a cultivated and undetermined Papaver sp., which is determined here as P. fauriei subsp. shimshirense based on the data shown by Takahashi and Yamagishi (2020) and the results in our phylogram. This would then be a case of infraspecific hybridisation. Xue et al. (2023) listed P. anomalum as Vulnerable (VU) in Russia under the name P. nudicaule var. aquilegifolium Fedde, which is considered a synonym of P. ammophilum by POWO (2023). Papaver anadyrense V.V.Petrovsky and P. tolmatschevianum were listed as Nearly Threatened (NT) by Xue et al. (2023).

The primary treatment of this group is Tolmachev (1975) in Arkticheskaya Flora SSSR. He included 16 species and seven additional subspecies and he was the author or co-author of no less than 19 of these taxa, the first ones described 52 years earlier, in 1923. Two species were described together with his pupil V.V.Petrovsky (Tolmachev and Petrovsky 1973), who continued with Papaver studies until his early 90s, also representing an almost 50-year-long career. After the passing-away of Tolmachev in 1979, another nine species and one subspecies were described by Petrovsky (1983, 1985). The study by Tolmachev (1975), which includes an identification key and distribution maps and the two studies by Petrovsky are here considered as a combined monograph, covering 24 species and eight subspecies. The treatment below only includes new or deviating information on the cited reference studies.

The species Papaver anadyrense, P. leucotrichum, P. microcarpum, P. nivale and P. ochotense listed by the cited monograph source have been removed from this part, as they do not or scarcely reach the Arctic (Elven et al. 2011) and P. microcarpum was discussed above as a primarily non-Arctic species. They are here, instead, treated in other geographical sections. Despite being accepted by POWO (2023), Papaver minutiflorum Tolm. had been synonymised with P. lapponicum subsp. orientale Tolm. by Petrovsky (1999) and Elven et al. (2011). These sources are followed here, whereas the recently-recombined name Oreomecon minutiflora (Tolm.) Krivenko and the recently-changed status of O. orientalis (Tolm.) Krivenko are both placed in synonymy. Papaver indigirkense Jurtzev was synonymised with P. minutiflorum by Peschkova (1994). Papaver radicatum subsp. occidentale C.E.Lundstr., mapped from Wrangell Island and the Chukotka Peninsula by Tolmachev (1975), was subsumed under P. radicatum Rottb. by POWO (2023). However, Petrovsky (1999) had already explained a broad interpretation of P. radicatum as a confusion with several morphologically similar Siberian species instead. This was in agreement with Solstad et al. (1999), who considered P. radicatum to be a Nordic species.

The remaining taxa from the monograph source used here were accepted by Elven et al. (2011), although four of them only provisionally. However, the need to better understand most of the taxa was underlined. Petrovsky et al. (2019) described three subspecies of the P. pulvinatum Tolm. complex. The previously misinterpreted name P. pulvinatum subsp. lenaense Tolm. was shown by Petrovsky et al. (2019) to be a synonym of P. nudicaule var. riparium V.V.Petrovsky. Chepinoga et al. (2023) lifted these subspecies to the species level with later recombinations into Oreomecon by Krivenko (2023). Similar recombinations and status changes were done for P. lapponicum subsp. jugoricum Tolm. and P. microcarpum subsp. czekanowskii Tolm. by Krivenko (2023), whereas a status change for P. nudicaule subsp. insulare V.V.Petrovsky was undertaken by Chepinoga et al. (2023). These species-level changes were done, based on the authors’ general non-acceptance of subspecific taxa and not by evaluating existing classifications in the Papaver literature, which is the preferred alternative here.

The Wrangel Island endemic Papaver uschakovii Tolm. & V.V.Petrovsky was accepted by Petrovsky (1999), Solstad et al. (2009), with molecular support and Elven et al. (2011) and is recombined into Oreomecon below. It was included in Papaver polare Tolm. by Xue et al. (2023) and POWO (2023) and was not treated by Krivenko (2023). According to Elven et al. (2011), Papaver uschakovii subsp. tichomirovii Kozhevn. from Chukotka, does not belong in P. uschakovii, nor in P. dahlianum s.lat. and may have affiliation with a still undescribed species.

A particular case concerns the species group with amphi-Beringian distributions, which comprise four species treated in the monograph sources. Papaver detritophilum Petrovsky has most of its distribution area on the Russian side and is treated within this group of Asian-Arctic species. Papaver keelei A.E.Pors., P. gorodkovii Tolm. & Petrovsky and P. walpolei A.E.Pors. have their major distribution ranges on the American side and are treated in the section on taxa from Arctic Alaska and Yukon; see below. We conclude that Oreomecon is represented by 14 species and six subspecies in Arctic Asia. Oreomecon lapponica and O. nudicaulis occur with separate subspecies in this area and their nominate subspecies are treated as taxa 3.6.6 and 3.1.13, respectively, below the areas where they occur.

The distribution map in Fig. 3 shows a gap in Central Siberia between groups A and C. The distribution maps by Peschkova (1994) only show a connection in easternmost Siberia. However, some occurrences are shown by GBIF (Global Biodiversity Information Facility) Secretariat (2023) along the Verkhoyansk Mountain Range and we map the connection here.

The most exclusive ones in this group are the endemic taxa from Wrangel Island, which were treated by Petrovsky (1997, 1999) and mapped by Petrovsky in Talbot et al. (1999), each shown from 4 - 8 localities and protected in the Wrangel Island State Reserve. Papaver gorodkovii Tolm. & Petrovsky was included by Petrovsky (1997), but, according to Petrovsky (1999), the disjunct and large Wrangel Island population of this mostly American species is polymorphic and insufficiently understood. The remaining five species and one subspecies mapped by Talbot et al. (1999) are endemic to Wrangel Island, except Papaver atrovirens V.V.Petrovsky also occurring on the adjacent mainland and P. calcareum V.V.Petrovsky also from north-eastern Chukchi Peninsula (Elven et al. 2011).

Xue et al. (2023) did not list any Endangered (EN) or Vulnerable (VU) species from the Asian Arctic, but treated seven taxa as Near Threatened (NT). These did not include the rare species from Wrangel Island, but instead widespread taxa such as P. czekanowskii and P. lapponicum subsp. jugoricum (Tolm.) S.V.I. Gudoshn. They also accepted P. indigirkense, which we, however, consider a synonym of P. lapponicum subsp. orientale.

Most of the taxa of Papaver sect. Meconella in this area are shared between the Arctic parts of Alaska and Yukon as defined by Walker et al. (2005) and the northernmost part of the North American Cordilleras, whereas other species predominate further south (Kiger and Murray 1997; Björk 2019; GBIF (Global Biodiversity Information Facility) Secretariat 2023). Distribution area D is, therefore, defined as Arctic Alaska and Yukon and adjacent parts of the northern North American Cordilleras delimited southwards by the border with British Columbia and eastwards by the Mackenzie River. The primary source for area D is Elven et al. (2011), where seven species centred in Arctic Alaska were included. Only three of these species were accepted under the same names by “Flora of North America” (Kiger and Murray 1997).

The list below includes amphi-Beringian species, including P. walpolei A.E.Porsild, which occurs in eastern Chukotka and P. gorodkovii Tolm. & V.V.Petrovsky, which also extends across the Bering Strait to Wrangel Island. According to Elven et al. (2011), P. keelei A.E.Porsild is by far the most common species in the Arctic part of the area, ranging from Chukotka to the western mainland of the Northwest Territories. It was not treated by Galasso et al. (2023), Grey-Wilson (2023) or Krivenko (2023) and is recombined into Oreomecon below. Papaver hultenii Knaben is common in Alaska and also occurs eastwards to Nunavut, but its presence in Chukotka is uncertain, according to Elven et al. (2011). None of these species occurs south of area D, except P. hultenii, known from the Pink Mt. area in British Columbia (Björk 2019). Björk (2019) reported that P. roseoalbum Björk is mainly from south-central Alaska, with a few collections outside area D in the far north-western part of British Columbia.

Neither Björk (2019) nor Krivenko (2023) referred to P. nudicaule subsp. americanum Rändel ex D.F.Murray, which was described by Rändel (1977) and validated by Murray (1995). The taxon was studied by morphology and AFLP by Solstad et al. (2009). They concluded that it was hexaploid as opposed to the typical forms of P. nudicaule and that it was the only American representative from southern and eastern Alaska and Yukon of a large complex including this species. It was also accepted by Elven et al. (2011), who did not recognise it from the Arctic parts of North America. In contrast, Kiger and Murray (1997) did not discriminate between this taxon and introduced “Iceland poppies” (P. croceum). The nominate subspecies of O. nudicaulis is treated here as taxon 3.1.13.

Krivenko (2023) omitted the author name in the citation of the basionym in his recombination of Oreomecon alaskanum (Hultén) Krivenko. Following the Code (Art 41.6; Turland et al. (2018)), this is considered to be within the range of allowed erroneous basionym citations. Krivenko (2023) also transferred Papaver denalii Gjærevoll, a species previously accepted by Björk (2019), to Oreomecon. However, Solstad et al. (2009) and Elven et al. (2011) considered it a synonym of P. mcconnellii Hultén. Galasso et al. (2023) treated P. macounii var. discolor Hultén as a subspecies of Oreomecon, while Krivenko (2023) raised it to species level. In contrast, Solstad et al. (2009) and Elven et al. (2011) considered it a synonym of P. keelei. The latter authors are followed here in both cases.

Papaver macounii Greene is probably the rarest species in this area, known from only a few scattered sites (Elven et al. 2011). Papaver alaskanum Hultén is also a rare species, but was considered heterogeneous by Elven et al. (2011). This heterogeneity has not yet been resolved. Cortés-Burns et al. (2009) included Papaver gorodkovii and mapped its distribution in their treatment of the rare plants of the Alaskan North Slope. However, there is no coordinated evaluation of the conservation status of Papaver sect. Meconella in North America. A total of eight species and one subspecies are listed below. Papaver mcconnellii was listed as VU and P. walpolei as NT in Russia by Xue et al. (2023).

The delimitation northwards of area E is the northern boundary of British Columbia. The reference study for this area is Björk (2019), primarily focusing on British Columbia, but also dealing with material from other parts and making significant changes to the taxonomy of the group. Papaver columbianum Fedde ex Björk and P. kluanense D.Löve only extend into adjacent areas of southern Yukon, according to Björk (2019), who also showed that most of the plants from the US part of the Rocky Mountains represent Papaver coloradense (Fedde) Fedde ex Wooton & Standley. The central part of the North American Cordilleras now includes five species.

The distribution map in Fig. 2 also integrated distribution maps presented by Kiger and Murray (1997).

Björk (2019) stated that both P. columbianum Fedde ex Björk and P. luculentum Björk may be rare. The former is only known from four collections. However, they are so far apart that the occurrence of undiscovered localities was cited to be likely.

The taxa present in the Canadian Arctic Archipelago were treated by Solstad (2007). However, the reference study for this area, where two widely distributed High-Arctic taxa are characteristic, is Elven et al. (2011). One of these taxa is Papaver cornwallisense D.Löve, while the other is Papaver dahlianum subsp. polare (Tolm.) Elven & Ö.Nilsson. Solstad et al. (2014) reported both to be very common in Svalbard and equally widespread in Arctic North America. Elven et al. (2011) had left the basionym of Papaver dahlianum subsp. polare unassigned, as its type housed at LE is from Svalbard and could potentially represent P. cornwallisense, a more recently described taxon. However, Solstad et al. (2014) confirmed that the type represents P. dahlianum s.lat. Hence, P. cornwallisense remains the name of this distinct taxon. It was not treated in any recent Oreomecon studies and is, therefore, transferred to Oreomecon here.

Russian authors have traditionally treated P. polare Tolm. as distinct at the species level and this view was recently maintained by Xue et al. (2023), POWO (2023) and Krivenko (2023), the latter recombining it into Oreomecon. However, all recent studies comparing this taxon with P. dahlianum Nordh., partly with molecular support (Nilsson 2001; Solstad et al. 2003; 2009; 2014; Elven et al. 2011), conclude that these taxa are conspecific and that the older name P. dahlianum holds priority. Nilsson (2001) divided Papaver dahlianum into a widespread High-Arctic subsp. polare and a Low-Arctic subsp. dahlianum Nordh. Papaver lapponicum subsp. dasycarpum Tolm., recorded from Novaya Zemlya by Tolmachev (1975), was tentatively treated within P. dahlianum by Elven et al. (2011) and an interpretation within subsp. polare is followed here.

The latter subspecies occurs in the southernmost part of the Arctic in Finnmark, Norway and adjacent mountains in the Kola Peninsula, where it was described as P. lujaurense N.Semenova (Semenova-Tian-Shanskaya 1956). Based on an AFLP-based molecular analysis, Solstad et al. (2009) rejected the segregation into two distinct subspecies and this view on Papaver dahlianum was shared by Elven et al. (2011). However, Elven et al. (2022) indicated this might not be a final conclusion given the existing morphological differences and the genetic markers used. They also indicated that P. dahlianum ssp. polare has recently been discovered in the southeastern part of the Municipality of Porsanger/Porsáŋggu/Porsangin in Finnmark, ca. 100 km S of the polar treeline. Recently, J.O. Olsen and others posted on Artsdatabanken (2024) a number of additional localities of Papaver dahlianum from a small area in the Municipality of Gáivuotna/Kåfjord/Kaivuonu another 200 km further to the southwest. As further studies of this complex continue, we maintain Nilsson’s interpretation (2001), which involves the acceptance of two separate subspecies of P. dahlianum.

Papaver lapponicum subsp. occidentale (C.E.Lundstr.) Knaben occurs in Canada and Greenland, whereas P. lapponicum subsp. lapponicum occurs from east Greenland eastwards to the westernmost parts of Siberia (Elven et al. 2011). The latter taxon was described from mountains just south of the Arctic border in the Kola Peninsula and two species described by Semenova-Tian-Shanskaya (1956) are considered synonyms. Papaver lapponicum subsp. lapponicum also occurs in the Municipalities Alta and Kvænangen in North Norway, ca. 80 km S of the Arctic tree line as defined by Elvebakk and Karlsen (2022). These populations have been treated as separate subspecies, but are included within subsp. lapponicum by recent authors, including Elven et al. (2022). Here, they are considered peripheral populations of an Arctic taxon and are not included amongst taxa listed from non-Arctic northern Europe.

Papaver labradoricum (Fedde) Solstad & Elven from Canada and Greenland was recombined at the species level by Elven and Murray (2008). The present treatment thus includes four species and two subspecies from this area and the only taxon restricted to the vast Arctic European area is P. dahlianum subsp. dahlianum.

The distribution shown in Fig. 2 includes all of Arctic Canada, Greenland and the European Arctic.

Papaver dahlianum s.lat. and P. lapponicum are both endangered (EN) in mainland Norway (Artsdatabanken 2021). Papaver lapponicum subsp. lapponicum is Red-listed at the regional and national level in Russia and its populations on the Khibiny and Lovozerskie Mountains in the Kola Peninsula are protected within nature monuments as shown by Andreeva and Uotila (1998), where P. lujaurense was included within P. lapponicum.

In his monograph on the alpine Papaver taxa in Scandinavia, Nordhagen (1932) described three new species. In addition, he described four new subspecies and two new varieties, including one variety of P. radicatum Rottb. He also briefly mentioned a ‘doubtful race’ (“± zweifelhaften Rasse”), which was intermediate between P. radicatum subsp. dovrense Nordh. and P. relictum (E.Lundstr.) Nordh., but it was not described. His suggested name, P. radicatum subsp. dovrense var. intermedium Nordh., for this taxon is, therefore, a nomen nudum, which makes later homotypic recombinations of this name illegitimate. A replacement name is, therefore, introduced below and a diagnosis is supplied; for a further description, see Nilsson (2001).

In a flora treatment, Löve (1945) described P. radicatum subsp. stefanssonii Á.Löve from Iceland, including both the white- or pink-flowered plants P. radicatum f. albiflora Stefánsson and P. radicatum f. rubriflora Stefánsson presented in the flora by Stefánsson (1901). However, like these, the taxon is illegitimate as no Latin diagnosis was provided (Art. 39.1 in the Code; Turman et al. (2018)) and the name cannot be applied to homotypic recombinations (Art. 6.4 in the Code; Turman et al. (2018)). Löve (1955, 1962b) interpreted the type material of P. radicatum to originate from Greenland and considered this species to be limited to Greenland and Canada. Löve (1955) considered Nordic material to belong to four species, namely P. steindorssonianum Á.Löve and P. stefanssonianum Á.Löve from Iceland and P. relictum and P. nordhagenianum Á.Löve from Scandinavia. In addition, he accepted P. lapponicum and P. laestadianum (Nordh.) Nordh. from northernmost Fennoscandia. By an epithet name change, Papaver stefanssonianum became the valid basionym of the taxon now often treated as P. radicatum subsp. stefanssonii, for example, by Nilsson (2001) and Wąsowicz (2020).

Löve (1962a) revised his concepts and transferred the octoploid species P. lapponicum and P. laestadianum to the subspecies level of his concept of the North American octoploid P. radicatum. In contrast, all Nordic decaploid taxa were united within one species. When merging P. nordhagenianum and P. relictum, he described five subspecies of P. nordhagenianum, three of which also have several varieties. His selected species is the younger of the two alternatives and, as already shown by Knaben and Hylander (1970), the recombinations are not in accordance with the priority rules. Thus, eight of the names published by Löve (1962a) are here considered illegitimate. Löve later reached the same conclusion, as he stated that all these taxa instead belong within P. relictum (Löve 1970). However, he only provided valid recombinations of the Icelandic-Faroese taxa.

Knaben (1958) and Knaben and Hylander (1970) argued convincingly why the type of P. radicatum originated in Iceland. The view that P. radicatum is a North Atlantic taxon known primarily from alpine localities in Norway, Sweden, Iceland (with secondary localities in lowland screes and river banks) and the Faroe Islands has been maintained later (Elven et al. 2011; 2022) and subspecific taxa described from elsewhere all represent other species (Solstad et al. 2003). Knaben (1970) stated that her intention was to treat the P. radicatum taxa at the variety level. However, she later concluded that this might have led to confusion in light of the high number of synonyms already published (Knaben 1985).

Most of the Scandinavian taxa were studied morphometrically by Selin and Prentice (1988) and Selin (1998, 2000), who referred to these taxa as subspecies. Nilsson (2001) treated 13 Nordic taxa at the subspecies level and provided morphological descriptions and a determination key. Solstad et al. (2003), however, did not find support for such a diversification, based on an analysis of isozyme patterns and a later AFLP-based study concluded on the presence of two groups, one comprising populations from northern Scandinavia, another one comprising populations from southern Scandinavia and Iceland (Solstad et al. 2009). Elven et al. (2011, 2022) maintained that the variation in the North Atlantic area does not, with one exception, merit recognition as a subspecies. In a checklist from Iceland, Wąsowicz (2020), on the other hand, recently accepted three subspecies and the distribution of two of these subspecies have previously been mapped, showing that they reach the Arctic parts of Iceland (Nilsson 2001).

Papaver radicatum has been a key issue in Nordic discussions on whether plant life survived the Weichselian glaciation or immigrated post-glacially, for example, the review by Solstad et al. (1999, 2003) and the discussion by Selin (2000). The species has been extensively studied by all generations of Nordic botanists, still without a unified conclusion on its taxonomy. However, Elven et al. (2022) remarked that future application of other genetic markers might instigate a revised taxonomic concept for this species. To reflect the Nordic name tradition and facilitate communication, Elven et al. (2022), therefore, treated nine formerly named taxa of P. radicatum from mainland Norway at the variety level; this was done as an informal treatment without providing the required recombinations. The same approach has been followed by Artsdatabanken (2024).

Below, we present a review of the classifications of the taxa within P. radicatum, with all important synonyms cited as presented in the original literature, involving a number of deviations from those listed by Nilsson (2001) and POWO (2023). In the absence of modern molecular data, we use morphological criteria and vicariant evolution as criteria for accepting subspecies, as underlined by Molinari (2023) and POWO (2023). Assessments of morphological differentiation rely on the morphometric studies by Selin and Prentice (1988), Selin (1998; 2000) and Øvstedal and Grung (2015).

In a study on five of the entities from southern Norway, Selin and Prentice (1988) concluded that P. radicatum subsp. intermedium (Nordh.) Knaben and P. radicatum subsp. oeksendalense Knaben were distinct, whereas P. radicatum subsp. groevudalensis Knaben and P. radicatum subsp. gjaerevollii Knaben were clustered quite closely with P. radicatum subsp. ovatilobum Tolm. from a neighbouring mountain area. When recombining these taxa in Oreomecon below, we therefore treat P. radicatum subsp. ovatilobum, P. radicatum subsp. oeksendalense and the new name of P. radicatum subsp. intermedium at the subspecies level. The former is the older of the three names from mountains further to the north in southern Norway and takes priority when P. radicatum subsp. groevudalensis and P. radicatum subsp. gjaerevollii are treated as synonyms, as done also by Nilsson (2001). Øvstedal and Grung (2015) concluded that the sixth southern Norwegian entity, P. radicatum subsp. relictum was morphometrically distinct from P. radicatum subsp. oeksendalense and deserved its position at the subspecies level, a conclusion followed here.

Concerning northern Scandinavia, Selin (1998) found P. radicatum subsp. subglobosum Nordh. to be morphologically distinct, whereas P. radicatum subsp. hyperboreum Nordh. and P. radicatum subsp. macrostigma (Nordh.) Nordh. were similar. The latter was originally described as P. radicatum subsp. hyperboreum var. macrostigma Nordh. by Nordhagen (1932). The local endemic P. radicatum subsp. avkoënse Knaben has not been studied morphometrically by the studies referred to above. Only P. radicatum subsp. subglobosum and P. radicatum subsp. hyperboreum are, therefore, recombined at the subspecies level below. Material from Iceland and the Faroe Islands has not been subject to morphometric analyses, except for unpublished data referred to by Selin (2000). Here, the taxon known as P. radicatum subsp. stefanssonii was related to south Scandinavian taxa in seed characters and to northern Scandinavian material in capsule morphology. It also deviates from all entities in its range of flower colours and is accepted here as a subspecies together with the nominate subspecies.

The conclusion below is that Oreomecon radicata is accepted with eight subspecies and four varieties from the Nordic area.

The exception referred to above is P. radicatum subsp. laestadianum Nordh., a name used for a taxon limited to a small alpine area of Troms in north Norway and adjacent Sweden (Solstad et al. 2009). It shares the chromosome number (2n = 56) with P. lapponicum, contrasting 2n = 70 for P. radicatum. However, P. radicatum subsp. laestadianum was not integrated into the biosystematic study by Knaben (1959a; b) as material was not available for her extensive cultivation experiments. Nannfeldt (1963) included it in P. lapponicum and Knaben (1983) concluded that it deserves status as a subspecies of P. lapponicum.

Tromsø Arctic-Alpine Botanic Garden holds material of P. radicatum subsp. laestadianum in cultivation from the locality Isdalsfjella/Njearrečazagáisi. This corresponds to the place name “Causigaisa” used in older maps and is within the area where the type material of this taxon was collected (Nordhagen 1932). Nordhagen reported it from two additional localities and provided illustrations of samples from two of them. However, he did not designate any type or mention any type of candidate and a lectotypification is therefore required. Amongst the syntypes at O and shown by Natural History Museum, University of Oslo (2023), there are annotations regarding two alternative typifications. One includes two sheets, O-V-2017486 and O-V-2017487, with at least five different individuals, as shown by the presence of tap roots, in addition to nine rosettes and 20 single leaves and references are given to illustrations from both sheets published by Nordhagen (1932, 1970). The annotations are undated and the handwriting is by T. Engelskjøn, although not formally documented. An alternative typification is presented by the annotation “Typus: individual marked ‘NB’ (by R. Nordhagen?) 30 Jun 1978, Gunvor Knaben”. This refers to the specimen to the far left on the latter of these sheets, which is a well-defined individual, as shown by its tap root. None of these annotations fulfils the requirement of effective publication (Art. 7.10 in the Code; Turland et al. (2018)) and the taxon is, therefore, lectotypified below. The specimen with Knaben’s annotation is selected as the lectotype. All additional specimens on six sheets in O are designated as isolectotypes.

Fig. 3 shows the capsule and leaf morphology of specimens from the comparative cultivation of four taxa in the Tromsø Arctic-Alpine Botanic Garden. Material from the lectotype locality of Papaver radicatum subsp. laestadianum shows clear affinity in capsule and leaf morphology with P. lapponicum subsp. lapponicum and appears very distinct from the two varieties of P. radicatum included. The black capsule hairs of our cultivated specimens are smooth in P. radicatum subsp. laestadianum and P. lapponicum, whereas they are decurrently dentate in both varieties of P. radicatum. It also differs in several minor characters from P. lapponicum subsp. lapponicum. We, therefore, interpret P. radicatum subsp. laestadianum as a subspecies of P. lapponicum, prior to its recombination in Oreomecon below. Its affinity to P. lapponicum is also supported by its chromosome number.

It should be added that a population of P. lapponicum subsp. laestadianum from the Mountain Márkos, which is situated ca. 15 km north of the type locality, was studied by Solstad et al. (2009) and by Nevermo (1997), both studies concluding on an affinity to P. radicatum. However, both Heggelund (1993), who presented its known distribution and Nevermo (1997) commented that plants on Márkos were morphologically heterogeneous. We, therefore, intend to bring samples from more populations of this taxon into comparative cultivation to test its possible heterogeneity pending future molecular studies.

Overall, northern non-Arctic Europe includes one species, distributed within Iceland, the Faroe Islands and the mountains of Scandinavia, in addition to one endemic subspecies of a different species (Fig. 2). The nominate subspecies of Oreomecon lapponica is treated as taxon 3.6.6 here.

Only the two fully-accepted subspecies of P. radicatum were treated by the Norwegian Red List (Artsdatabanken 2021), both as EN. These subspecies are subsp. radicatum and subsp. laestadianum. In Sweden, these two taxa are assessed as NT and VU, respectively (Eide et al. 2020). Papaver radicatum subsp. stefanssonii Knaben was treated as Vulnerable (VU) in Iceland (Wąsowicz and Heiđmarsson 2019) below its homonym P. radicatum subsp. stefanssonii (Á.Löve) Jonsell & Ö.Nilsson.

Kadereit (1990) monographed the Papaver alpinum L. complex, including eight subspecies with mostly non-overlapping distribution ranges. All these subspecies were later subject to an RAPD analysis, which produced five weakly-supported geographically-based clusters (Bittkau and Kadereit 2002). The correlation with subspecies was low. They also analysed four subspecies with respect to ITS1 sequences, which did not show any differentiation.

Schönswetter et al. (2009) studied 12 named entities by using DNA sequencing, AFLP fingerprinting and morphological traits. They concluded with a similar set of four weakly-supported geographically-based groups (Slovenia, Balkan, most of the Alps/Tatra, Central Italy) and two more strongly-supported groups from south-eastern France and the Pyrenees. They did not find any consistent morphological or molecular characters differentiating the taxa. They concluded that all the previously named variation was best treated within a single, widely defined species, Papaver alpinum, except for the Iberian entity, which was accepted as P. alpinum subsp. lapeyrousianum (Gutermann ex Greuter & Burdet) Kerguélen. They found most sampled population groups or populations to be genetically distinct and explained this as genetic drift within diploid and rapidly reproducing plants in often small populations. The concept of P. alpinum used by Schönswetter et al. (2009) was followed by Banfi et al. (2022) when the latter recombined P. alpinum and its subsp. lapeyrouseanum into Oreomecon, although Banfi et al. (2022) applied a different subspecies epithet for the Iberian entity.

The classification system by Schönswetter et al. (2009) has been followed by many treatments, such as Hassler (2023a, b), although the two latter studies made an exception for Papaver tatricum (A.Nyár.) Ehrend. ex Soó and P. tatricum subsp. fatraemagnae Bernát, which were accepted as separate entities. POWO (2023) accepted a widely defined Oreomecon alpina. However, they also made exceptions by maintaining four taxa in the complex as separate Papaver species. Flora Gallica (Tison and de Foucault 2014) also adopted P. alpinum in a broad sense. In contrast, other major floras from the area, for example, Flora Helvetica (Lauber et al. 2018) and Flora d’Italia (Pignatti et al. 2017), adopted a multi-species approach.

Fragnière et al. (2020) and Pittet et al. (2020) studied in detail Papaver occidentale (Markgr.) H.E.Hess et al., a white-flowered species from the western Alps. It appears similar to the other white-flowered species, P. alpinum s.str., P. sendtneri Kern. ex Hayek and P. tatricum (A.Nyár.) Ehrend. and might be characterised as the least distinct taxon, at least from its original description as Papaver alpinum subsp. tatricum var. occidentale Markgr. (Markgraf 1958a). Based on a detailed genetic study, Pittet et al. (2020) concluded that P. occidentale is a genetically and morphologically well-defined entity. It has apparently survived the Late Glacial Maximum both in periglacial areas and in nunatak situations. They underlined that further studies are needed to sort out the taxonomy of this complex.

The emerging pattern is that of an immigrating ancestral taxon into Central Europe, which had split into a western and a central group, with further differentiations leading to genetically distinct populations in numerous discrete areas (Schönswetter et al. 2009). As indicated by Schönswetter et al. (2009), the immigration and expansion situations are more likely to have taken place during a glacial period. In contrast, an interstadial represents a bottleneck situation favouring isolation and differentiation within this complex.

The studies by Bittkau and Kadereit (2002) and Schönswetter et al. (2009) indicate that some names do not correlate with the patterns in the molecular studies. This mismatch in the data by Bittkau and Kadereit (2002) would have been reduced if accepting P. aurantiacum Loisel. and P. alpinum subsp. occidentale. The southern populations of P. alpinum subsp. kerneri (Hayek) Fedde in Bosnia and Herzegovina and Montenegro may also represent separate entities, according to data from Schönswetter et al. (2009). With their present names, plants in central Italy do not match the molecular data shown in these two studies. Conversely, other names appear to be redundant, for example, P. alpinum subsp. victoris (Škornik & Wraber) Wraber from Slovenia, although the conclusion by Škornik and Wraber (1988) was based on a comparison with the neighbouring species. When treating this difficult complex within Oreomecon, we find that plants of the central group are better maintained at the subspecies level than left unnamed. The study by Schönswetter et al. (2009) is here used as the main source on nomenclature.

Markgraf (1958a) is the only study on the complex where type localities are indicated, although with incomplete information. The Bulgarian Papaver alpinum subsp. degenii (Urum. & Jáv.) Markgr. was cited with type specimen from “El Tepe, Pirin, 1915, Dimonie“, whereas the locality which had been presented in the protologue by Urumov (1920) was “in graminosis aridis m. Pirin, legi 1915” without collector information. In a biography on Mihael Dimonie, Pachschwöll et al. (2019) presented his botanical activities, indicating that he instead only visited the Pirin Mountains in June, July and August 1909. The area was then within the Ottoman Empire and the peak of Mt. Vihren was then referred to as El Tepe or Jel-tepe. His only collections surviving two fires are those distributed commercially to several herbaria under the heading “Plantae Macedonicae”. Three of his collections of this taxon from Vihren at WU, as documented by Virtual Herbaria JACQ (2024), have slightly different label texts from the one in the protologue by Urumov (1920). However, in the absence of any known collections from 1915, these are designated as lectotypes and isolectotypes below. The label texts are identical, except that the lectotype includes altitude information.

According to Schönswetter et al. (2009), Papaver aurantiacum Loisel. was described in Flora Gallica (Loiseleur-Deslongchamps 1807). However, it was described in a later supplement (Loiseleur-Deslongchamps 1809), where it was compared with the leaves and flowers of Papaver alpinum and where a type specimen was cited for having been collected at Mont Ventoux by M. Requien. We suppose the holotype specimen is at P, but we have not been able to trace it there or elsewhere.

Zapałowicz (1911) described Papaver corona-sancta-stephani Zapał. as common at 2000–2200 m alt. on the northwest slope of Mt. Ineu (= Vârful Ineu, Munţii Rodnei) in the Romanian Carpathians and Paszko et al. (2020) indicated that the type is housed at KRAM. Zapałowicz (1911) described the type locality, but did not select a type. We have seen six vouchers of the typical form from KRAM. The article by Zapałowicz (1911) was published in October 1911 and a collection made in August 2011 by D. Herbich is referred to. Therefore, four vouchers from the period August 2010 to August 2011 are candidates for lectotypification. Below, we designate the specimen out of the five that presents the best-developed floral buds as the lectotype. Zapałowicz (1911) also described Papaver corona-sancta-stephani f. hispidulum Zapał. and P. corona-sancta-stephani var. angustisectum Zapał. from the same locality. The former is present as a single collection at KRAM and is interpreted by us as the holotype. The latter is lectotypified below, while both are listed as heterotypic synonyms of P. corona-sancta-stephani s.str.

Markgraf (1958a) is correct in stating that the name Papaver rhaeticum Leresche was first mentioned by Gremli (1874) in the second edition of his “Excursionsflora für die Schweiz”. however, on p. 80 and not on p. 66, as repeatedly stated in basionym citations. Page 66 instead refers to the similar treatment in the sixth flora edition (Gremli 1889), as indicated by Fedde (1909). In both these floras, the name is presented as a nomen nudum and the treatment by Gremli (1889) is only ‘like P. pyrenaicum, but only in Engadin’. Nyman (1889) recombined it as P. alpinum subsp. rhaeticum (Leresche) Nyman and Banfi et al. (2022) corrected its author citation to P. alpinum subsp. rhaeticum (Leresche ex Gremli) Nyman. The first valid description of the taxon was made by Markgraf (1958a: 311), who also cited its type specimen from Oberengadin in Switzerland. He did not cite its herbarium affiliation and we have not been able to trace it. Markgraf (1958a) cited his taxon as “Papaver alpinum subsp. rhaeticum (Ler.) Mkr.”. The correct citation appears to be P. alpinum subsp. rhaeticum (Leresche ex Gremli) Nyman ex Markgr. for what is the basionym of a described taxon. However, the name presented by Markgraf (1958a) is illegitimate (Art. 6.4 and 58.1 in the Code, Turland et al. (2018)) and a new homotypic replacement name honouring F. Markgraf is, therefore, introduced below.

Nyárády (1942) described Papaver alpinum subsp. tatricum A.Nyár. from ‘Tatri Magni’ without adding a type. He described P. alpinum subsp. tatricum var. angustisectum A.Nyár. and P. alpinum subsp. tatricum var. latisectum A.Nyár. with illustrations of leaves from several collections from the Tatra Mountains. He also cited two collections of P. alpinum subsp. tatricum from Haute-Savoie in France; however, did not describe the nominate variety of this subspecies. Markgraf (1958a) described the plants from France as P. alpinum subsp. tatricum var. occidentale Markgr. with one of the samples mentioned by Nyárády (1942) as the holotype. He also provided a diagnosis of P. alpinum subsp. tatricum var. tatricum A.Nyár. and listed as type a collection from Hohe Tatra with Nyárády as collector. This is defined here as the lectotype of P. alpinum subsp. tatricum, but we have not been able to localise it. The type of Papaver sendtneri Kern. ex Hayek at B is possibly a holotype, but we have not been able to verify whether duplicates exist, requiring a lectotypification.

Krivenko (2023) recently recombined one of the entities of the O. alpina complex as Oreomecon tatrica (A.Nyár.) Krivenko, whereas Grey-Wilson (2023) introduced the name Oreomecon corona-sancti-stephani (Zapał.) Grey-Wilson. Both these authors selected single taxa from amongst those included within a broad concept of O. alpina as defined by Banfi et al. (2022), leaving the remaining ones embedded in O. alpina without explaining why these did not deserve similar treatment. As they did not cite any studies supporting these selected recombinations, the two names are not accepted below.

On the other hand, the western entities were well separated from the remaining samples in the analysis by Schönswetter et al. (2009) and the Iberian plants are treated as a separate species here. As shown by Banfi et al. (2022), the name P. pyrenaicum subsp. suaveolens P.Fourn. is heterotypic as compared with P. suaveolens Lapeyr. The latter is illegitimate since the earlier name P. aurantiacum Loisel. was cited as a synonym, which prevents the epithet “suaveolens” from being adopted at the species level for the basionym P. pyrenaicum subsp. suaveolens P.Fourn. Greuter (1981) introduced the name Papaver lapeyrousianum Gutermann ex Greuter & Burdet. Banfi et al. (2022) concluded that this name has priority at the species level, while Ferrer-Gallego (2024) recently recombined it into Oreomecon.

Kropf et al. (2006) studied the Iberian populations and concluded on vicariance in the development of populations both in the Sierra Nevada, the eastern Pyrenees and the western Alps, while long-distance dispersal, surprisingly from Sierra Nevada to Central Pyrenees, explains the latter populations. Relying on genetic structure and morphological dissimilarity, they concluded that the eastern Pyrenean populations are different and deserve a separate variety name, which had been introduced by Ascherson (1869). Both Bittkau and Kadereit (2002) and Schönswetter et al. (2009) confirm that the Iberian populations are heterogeneous. Thus, we follow Kropf et al. (2006) and conclude that the Sierra Nevada and Central Pyrenean populations represent one distinct subspecies within Papaver lapeyrouseanum, namely subsp. lapeyrouseanum, which is different from the east Pyrenean P. lapeyrouseanum subsp. endressii (Asch.) Greuter & Burdet.

The AFLP analysis by Schönswetter et al. (2009) showed that both the Iberian material and samples corresponding to P. aurantiacum are genetically very distinct from the remaining parts of the complex. We also recombine the latter taxon at the species level below to reflect this pattern.

The present list of accepted taxa includes three species with 11 additional subspecies distributed within the area presented in Fig. 2.

Fragnière et al. (2020) conclude that P. occidentale is doomed to extinction in the wild due to rapid global warming. Their hypothesis can probably be extended to other taxa of the group. Papaver aurantiacum, P. occidentale and P. sendtneri are Red-listed as near threatened (NT) in Switzerland (Bornand et al. 2016) and P. alpinum s.lat. is threatened in Germany (Metzing et al. 2018). From Sierra Nevada, Blanca et al. (2002) presented the orange-flowered P. lapeyrousianum as forming a single population of less than 2,500 individuals known from four very small subareas between 3,200 and 3,450 m a.sl., near the peak of Mulhacén. The Sierra Nevada population is obviously in danger, as opposed to the larger populations in the Pyrenees, which are considered to be of least concern (LC).

Papaver degenii is a local endemic of the Mountain Pirin in Bulgaria, where it is rare and occurs between 1,915 and 2,850 m alt.. It has been treated at the species level and as vulnerable (VU) both by Stoeva (2009) and by later online versions of the Bulgarian Red Data Book (Stoeva 2023), where a distribution map shows three population centres, with single minor occurrences, each consisting of 20–60 individuals over areas of only a few m². The species is protected and listed as a glacial relict. Gorgorov et al. (2011) showed that the taxon had reduced sexual reproduction capacity and they tried in vitro propagation as an additional effort in ex-situ conservation. In Romania, the distribution and ecology of P. alpinum subsp. corona-sancti-stephani (Zapał.) Borza was presented by Bartók et al. (2016) and its Red-list status in Romania was cited as “rare”, referring to Oltean et al. (1994). The rarest taxon in Central Europe is probably P. tatricum subsp. fatraemagnae Bernát., a taxon with deviating flowers with wedge-shaped petals known from limestone slopes at only 890 m altitude, at a locality in Slovakia, where it is isolated from the distribution area of P. tatricum s.str. (Bernátóvá 2002).