Sibbaldianthe orientalis (Soják) Mosyakin & Shiyan 2017

Mosyakin, Sergei L. & Shiyan, Natalia M., 2017, The genus Sibbaldianthe (Rosaceae): a nomenclatural overview and new combinations, Phytotaxa 296 (2), pp. 101-117 : 110-111

6. Sibbaldianthe orientalis (Soják) Mosyakin & Shiyan , comb. nov.

Basionym: Schistophyllidium bifurcum (L.) Ikonnikov (1979: 210) subsp. orientale Soják (2008: 357 ; authorship cited as “Juz. ex Soják”).

Type (holotype, PR: Soják 2008: 357):— TURKEY: “Turсia oriеnt., in prаtis propе laс. Van, 12. VI.1977, Soják s. n. ( PR)”.

Invalid names:

Potentilla orientalis Juzepczuk (1934 [published 1935]: 124, in adnot.; 1941: 82), nom. inval., descr. ross. ≡ Potentilla bifurca L. subsp. orientalis Soják (1970: 113 ; authorship cited as “(Juz.) Soják”), nom. inval. ≡ Schistophyllidium orientale Ikonnikov (1979: 210 ; authorship cited as “(Juz.) Ikonn.”), nom. inval. ≡ Sibbaldianthe bifurca (L.) Kurtto & T. Eriksson (2003: 139) subsp. orientalis Kurtto & T. Eriksson (2003: 139 ; authorship cited as “(Juz.) Kurtto & T.Eriksson”), nom. inval. ≡ Schistophyllidium bifurcum (L.) Ikonn. subsp. orientale [Juz. ex] Soják (2004: 307), nom. inval. (nom. provis., cited as “in press”).

Soják (2008: 357) cited the authorship of his Schistophyllidium bifurcum subsp. orientale as “Juz. ex Soják”. The authorship of that name can be attributed solely to Soják, according to Art. 46.4 of ICN ( McNeill et al. 2012): “When the epithet of a validly published name is taken up from and attributed to the author of a different binary designation that has not been validly published, only the author of the validly published name may be cited.”

Sibbaldianthe orientalis differs from S. bifurca mainly in having appressed pubescence of stems, branches, pedicels, and petioles. It is one of the most widespread taxa of the S. bifurca aggregate, occurring from southeastern parts of Europe to Central Asia and China (occasionally as alien in other regions). According to Soják (2005: 70), “in all the territory from Rumania to Hebei ( China) and southern Mongolia only plants with characters of P. orientalis occur but not of P. semiglabra .”

Potentilla orientalis was accepted as a species separate from P. bifurca in many floras, identification manuals and checklists, mainly those covering the territories of the countries of the former Soviet Union (Juzepchuk 1941; Blinovskiy 1949; Bochantsev 1955; Kashchenko 1957; Fedorov 1958; Baytenov 1961; Czerepanov 1995; Yakubov 1996; Mosyakin & Fedoronchuk 1999; Lazkov & Sultanova 2014 etc.) and also Mongolia ( Grubov 1982; Gubanov 1996). However, its records from the southeastern part of Siberia (where S. bifurca sensu stricto mainly occurs) are now considered doubtful ( Kurbatskiy 1988, 1912). In some recent publications, the name Sibbaldianthe bifurca subsp. orientalis was cited either as the accepted ( Yena 2012) or alternatively acceptable ( Ostapko et al. 2010) name.

Other authors ( Ball et al. 1968; Schiman-Czeika 1969; Peşmen 1972; Kamelin 2004 etc.) treated P. bifurca in a wide circumscription, either not mentioning the name P. orientalis at all, or citing it in synonymy. In the Flora of China ( Li et al. 2003) and the new Mongolian checklist ( Urgamal et al. 2014) P. bifurca , together with the next species (see below), is accepted as Potentilla bifurca var. major Ledeb. Kamelin (2004) also treated Potentilla bifurca widely and listed P. orientalis and P. semiglabra as synonyms. However, he admitted that plants with appressed and non-appressed trichomes could be possibly recognized, respectively, as two subspecies, but commented (without discussing the lectotype of P. bifurca ) that the typical subspecies should include both appressed-pubescent and partly glabrous plants, thus, by implication, placing both P. orientalis and P. semiglabra in synonymy of P. bifurca subsp. bifurca . Soják (2005: 70) criticized these statements and noted that “ P. semiglabra is a good species with constant characters and own distribution area. Potentilla orientalis has also been treated either as species or subspecies. Transitions among these three taxa occur in places where their primary distribution areas overlap and where hybridization can be expected, or in synanthropic habitats in European Russia.”

In 2007 Soják accepted Potentilla moorcroftii as a species and listed Potentilla bifurca subsp. orientalis as its synonym. He also noted ( Soják 2007: 289) that “[t]ransitional forms between P. bifurca s. str. and P. moorcroftii can occasionally be found (mainly in areas where both species co-occur or at synanthropic East European localities), probably of hybrid origin.” In this sentence, the name P. moorcroftii refers to taxa accepted here as Sibbaldianthe moorcroftii and S. orientalis . To add to that, later Soják (2009: 215–216) commented that “Juzepczuk (1941), followed by other authors of the former USSR, differentiate between the steppe Potentilla orientalis Juz. and high mountain P. moorcroftii Wall. ex Lehm. My field study in Tien Shan and Mongolia has revealed that S. orientale gradually changes into S. moorcroftii as altitude increases. I am convinced that distinguishing between the two taxa at the species or subspecies rank is untenable.The identity of both“species” has been indicated by my cultivation experiments.” However, he also admitted that “[t]o confirm my opinion, further experiments would be useful. Transitional populations exist in certain areas, especially those where distributions of S. [ Schistophyllidium — S.M. & N.S.] orientale and S. bifurcum overlap or are contiguous. I have observed them in southern Mongolia and they are frequent in synanthropic habitats of central and eastern part of European Russia. These taxa are best treated as subspecies.” In his earlier publications, as well as in some annotations of herbarium specimens, Soják recognized P. moorcroftii as a separate species. Thus, Soják changed his mind several times regarding the taxonomic status (species or subspecies) of the taxa accepted here as Sibbaldianthe moorcroftii and S. orientalis . In his latest article published posthumously, Soják (2012) accepted Schistophyllidium bifurcum subsp. orientale Soják (2008) but cited Potentilla bifurca subsp. moorcroftii (Wall. ex Lehm.) Soják ex Panigrahi (1991) as its synonym, which is evidently nomenclaturally incorrect. If Sibbaldianthe moorcroftii and S. orientalis are treated as the same taxon (either a separate species or a subspecies of S. bifurca ), the epithet “ moorcroftii ” is of priority at the ranks of both species and subspecies (Art. 11.2 of ICN: McNeill et al. 2012). The species status of these taxa is preferred here.