Jacobaea taurica (Asteraceae), the new combination for a Crimean protected species

Senecio tauricus (Asteraceae) was described as an endemic species restricted to the mountain plateaus (yailas) of the Crimean Peninsula, growing only in meadow-steppe plant communities. The species status for this taxon was accepted in all relevant floras, identification manuals, and checklists; it is also listed in the current edition of the Red Data Book of Ukraine (2009) and some other lists of protected plant species. Following the results of recent molecular phylogenetic studies that justified the segregation of several genera housing taxa earlier placed in Senecio sensu lato, the new nomenclatural combination Jacobaea taurica is proposed. Basic information on morphology, ecology and distribution of J. taurica and related taxa is also briefly discussed and summarized.

number of ray florets and of inner involucral bracts ("13, not 21", as given in the protologue).
Following its description in 1985, S. tauricus was accepted as a distinct species in all relevant floras, identification manuals, and checklists covering plants of Ukraine and Eastern Europe in general (Katina, 1987;Konechnaya, 1994;Mosyakin, Fedoronchuk, 1999;Yena, 2012). In his analysis of endemism of the Crimean flora, Yena (2001Yena ( , 2008Yena ( , 2012 also accepted this species and recognized it as a local endemic of the Crimean Peninsula.

Ecology of Senecio tauricus
Senecio tauricus seems to be geographically and ecologically restricted to meadow and meadow-steppe plant communities of the treeless plateaus (yailas) of the Crimean Mountains (see distribution maps and associated information in Yena, 2009;Rudenko, 2015), while Jacobaea vulgaris (= Senecio jacobaea) occurs in a much wider range of open habitats throughout the Crimean Peninsula, including steppe, flatland and foothill meadows, and ruderal plant communities. Judging from available herbarium specimens and field observations, J. vulgaris occurs on yailas very rarely, more likely accidentally due to human activities (transport, tourism etc.). It should be also noted that yaila areas are the most endemic-rich habitats of Crimea, with more than 50% of the currently recognized ca. 106 Crimean endemic vascular plant species occurring here (Yena, 2008). The high diversity of endemic plants in these habitats is partly explained by the diverse altitudes and complexity of landscapes therein, as well as by the complex patterns of geological and biogeographic history of the Crimean region (for further details see Yena, 2008Yena, , 2012Cordova, 2015 and references therein).
According to the new classification proposed for habitats of the Crimean Mountains (Didukh et al., 2016), the actual and expected habitats of S. tauricus belong to the following categories and subcategories: E1.25 Crimean meadows (E1.251 Meadows on deforested areas, and E1.252 Meadow biotopes on yaila karst funnels) and E2.15 Mountain meadow steppe biotopes (E2.1512 Biotopes of mountain sod meadowsteppes on well developed chernozems of highland yailas). According to the EUNIS Habitat Classification (European Environment Agency, 2014-onward;Didukh et al., 2016;Onyshchenko, 2016), such habitats mainly belong to the category E2.251: Ponto-Pannonic mesophile hay meadows. combinations or names in the currently recognized genera either were available earlier or have been validated recently. In particular, new combinations for taxa transferred to Jacobaea and other segregates of Senecio have been proposed by Pelser et al. (2006), and then Nordenstam (2006) and Nordenstam andGreuter (in Greuter, Raab-Straube, 2006, 2007) in the course of preparation of the treatment of Asteraceae for the Euro+Med PlantBase Project (Greuter, 2006-onward;Greuter, Raab-Straube, 2008). Totally more than 90 new combinations in Jacobaea were published for species and infraspecific taxa since 2006 (IPNI, 2017onward). However, no transfer of Senecio tauricus (at any rank) to Jacobaea has been proposed yet, and the species is still recognized in Senecio in the Euro+Med PlantBase (Greuter, 2006-onward) and The Plant List (2013-onward), as well as in recent basic reference publications covering the flora of Crimea (Yena, 2009(Yena, , 2012Rudenko, 2016, etc.).

Taxonomic history of Senecio tauricus
In Flora Taurica (Privalova, 1969), there was only a note under Senecio jacobaea with some considerations regarding peculiarities of the plants from the Crimean treeless mountain plateaus locally called yailas (yaila in singular; derived from the Crimean Tatar [Qırımtatar] language, meaning summer pasture or summer rangeland; also jaila or yayla in some other Turkic languages): "Plants from the yaila are often of stocky habit, with large heads and long ray florets that are twice as long as the involucre" (Privalova, 1969: 228; in Russian: "Яйлинские растения часто имеют более приземистый рост, крупные корзинки и длинные язычковые цветы, вдвое превышающие длину обертки"). Konechnaya (1985) later described those plants as Senecio tauricus, an endemic species restricted to the Crimean Mountains. According to the protologue, this species differs from S. jacobaea (now Jacobaea vulgaris) in having lower height, lesser number of heads (capitulae) within the terminal corymb, and noticeably larger heads, longer ray florets and involucral bracts. It was also compared in the protologue with S. ambraceus Turcz. ex DC. (Candolle, 1838: 348; now Jacobaea ambracea (Turcz. ex DC.) B. Nord. : Nordenstam, 2006: 13) known to occur mainly in southeastern Siberia, the Russian Far East (south), Mongolia, northern China, and Korea (Chen et al., 2011;Zuyev, 2012), from which the Crimean species was reported to differ in a lesser been not yet treated as an infraspecific taxon of any other species. Judging from the information available from the cited and some other references and from selected herbarium specimens (consulted mainly in CSAU and KW), we were unable to establish possible identity of the Crimean plants with any currently recognized infraspecific taxon of J. vulgaris or related species occurring in the neighboring regions (mainland Ukraine, SW European Russia, Central Europe, the Caucasus, the Balkans, etc.). In terms of their gross morphology and especially habit, the stout but rather low-growing Crimean yaila plants are evidently different from typical forms of the tetraploid subspecies (Jacobaea vulgaris subsp. vulgaris) and also from octoploid subspecies [J. vulgaris subsp. gotlandica  (Tzvelev, 1986;Konechnaya, 1994;Greuter, Raab-Straube, 2006).
Thus, at present we prefer to maintain S. tauricus as a separate species of Jacobaea, pending further research. Additional comparative morphological, karyological, and molecular phylogenetic studies are needed for identifying the precise phylogenetic position, origin, and the best-suitable taxonomic rank of the Crimean montane plants related to J. vulgaris and accepted in recent literature as S. tauricus. We hope that this nomenclatural note will attract attention of researchers to this still poorly known taxon and will stimulate its much-needed further detailed studies in comparison with other taxa of the J. vulgaris aggregate.

Conservation status of Senecio tauricus
Senecio tauricus is listed in the 3 rd (current) edition of the Red Data Book of Ukraine (Yena, 2009) with the conservation status "Rare"; it is also included in some other regional "red lists" (List…, 2013;Rudenko, 2015; the first list is part of the Ukrainian legislation; the second list has no legal status in Ukraine). The reported main threat factors for that species are its narrow

Morphology of the species, with considerations of its relationships
Judging from morphological characters of plants from the Crimean Mountains, they are indeed closely related to Jacobaea vulgaris, differing from the latter mainly in some quantitative characters, particularly those mentioned in the protologue (see above). As a result of examining numerous specimens of this and related species available in KW and CSAU (herbarium acronyms following Thiers, 2017-onward), we can additionally note that S. tauricus also differs from J. vulgaris in having rosettes more persistent at maturity, glabrous (almost totally hairless) leaves, wider ray florets, and especially well-developed black widely triangular marks on the tips of inner involucral bracts (in Crimean plants of J. vulgaris sensu stricto these black marks are narrowly triangular, hatched, or nearly absent).
It was convincingly demonstrated recently that J. vulgaris is a morphologically and karyologically diverse and variable species (or species aggregate) represented by several cytotypes (ranging from diploids to octoploids, with occasional presence of some aneuploids) and weakly delimited morphotypes, now often treated as subspecies and/or varieties (Wysk et al., 2009;Hodálová et al., 2010Hodálová et al., , 2015Conti et al., 2012;Mereďa et al., 2016a, b). Some ecological preferences of these entities were also reported, but their geographical ranges remain insufficiently known (Mereďa et al., 2016a, b). These studies already indicated that octoploids and hexaploids tend to have (among other characters) somewhat longer ray florets, involucral bracts and tubular florets, as compared to the tetraploid cytotype of J. vulgaris (Hodálová et al., 2015;Mereďa et al., 2016b). Rather long ray florets and involucral bracts are also peculiar to the Crimean montane plants, which may suggest their higher ploidy level(s). However, no ploidy information is available yet for these Crimean plants.
No synonyms or infraspecific entities have been reported or validated so far for S. tauricus. It also has ecological niche, afforestation of yailas, local livestock grazing, recreation, and potentially also climate changes that may result in aridification and transformation of yaila meadow-steppe plant communities. No special populational studies of the species have been performed so far; thus, data on its populations are scarce.