Artemisia verlotiorum ( Asteraceae ) in the continental part of Ukraine : now in Kyiv

Colonies of Artemisia verlotiorum (Asteraceae), an alien species of East Asian origin now widespread in many countries of the world, were found in 2018 in Kyiv in the Syrets Arboretum (Syretskiy Dendropark) and in a nearby abandoned plant nursery and greenhouses. At present, three clonal colonies have been revealed. Most probably rhizomes of that species were initially introduced to Kyiv with soil and/or imported trees and/or shrubs. However, one colony (along the wall of the administrative building of the arboretum) most probably emerged from seeds dispersed by wind from the main (supposedly initial) colony in the abandoned nursery. Before our find in Kyiv, A. verlotiorum was reliably known in Ukraine in Crimea (reported since the 1920s), Transcarpathia, and from Lviv (recent records, to be discussed in detail in a forthcoming article). Most probably A. verlotiorum is spreading in Eastern Europe mainly by rhizome fragments with soil and plant material. Other alien taxa of the Artemisia vulgaris group (especially A. umbrosa and A. argyi) occur in Ukraine mainly as "railroad" plants.

The specimens of A. verlotiorum collected in Kyiv in 2018 (see below) are deposited in the National Herbarium of Ukraine (KW).Herbarium acronyms mentioned in the article follow Thiers (2008-onward).

Earlier records of Artemisia verlotiorum in the territory of Ukraine
The first known occurrence of A. verlotiorum in Ukraine, and in Eastern Europe in general, was reported by Gams (1929) in the 1920s, who mentioned, although with some doubt, that he observed this species as a weed in the Nikita Botanical Garden: "… der Bearbeiter (Gams) konnte sie hier nur im Garten von Nikita auf der Krim als Unkraut feststellen" (Gams, 1929: 631).However, that record was neglected and the species has not been reported in floras and other publications covering the territory of Crimea.This record was confirmed later, first based on observations by Dubovik (see Mosyakin, 1990;Dubovik, Mosyakin, 1991) and then by Mosyakin (2006), who indicated the continued presence of A. verlotiorum in Nikita (Yalta area) in and near the Nikita Botanical Garden.Our analysis (by Boiko) of herbarium specimens of the Nikita Botanical Garden -National Science Center (YALT) demonstrated that the species was often collected in this area for many years, but it was misidentified as A. vulgaris (see Boiko, 2009).Special surveys (by Mosyakin and Boiko, before 2014) also demonstrated that A. verlotiorum is now widespread in the Crimean South Coast.In particular, we registered this species in Yalta, Gurzuf, Partenit, Koreiz, where in some localities the plants formed dense and large stands (Mosyakin, 2006;Boiko, 2009).At present the species should be considered as fully naturalized in Crimea (at least in the South Coast area).
Artemisia umbrosa (also known under misapplied names "A.codonocephala" auct.non Diels, "A.dubia" auct.non Wall.ex Besser, and "A.lavandulifolia" auct.non DC.; see Mosyakin et al., 2018) is also reported in Crimea (Yena, 2005(Yena, , 2012;;Seregin at al., 2015), but it seems to be much rarer there than A. verlotiorum s. str.However, at least some (or most probably all?) records of "A.dubia" by Seregin et al. (2015) in fact belong to A. verlotiorum s. str.; in particular, the following specimens from MW: MW0628959, MW0628960, MW0628961, MW0628962 (images available from Moscow Digital Herbarium: Seregin, 2019).These specimens from Sevastopol and Balaklava correspond to records in the article by Seregin et al. (2015) and because of that the occurrence of A. umbrosa ("A.dubia" sensu auct.) in that area is in need of confirmation.
Cultivation of A. verlotiorum by Boiko in the Donetsk Botanical Garden of the National Academy of Sciences of Ukraine in 2005-2014 demonstrated that the plants in this region normally develop numerous vegetative shoots and under favorable conditions reach the flowering and fruiting stages.Because of that it has been suggested that further dispersal of the species in the continental part of Ukraine is quite possible (Boiko, 2009).
Probably the first mention of A. verlotiorum for the continental part of Ukraine was made in the editorial note to the article by Boiko (2009: 834): "A.verlotiorum також знайдена, за даними В.В.Протопопової, в м.Ужгороді в палісаднику біля вокзалу; в Чернівецькій обл.поряд із залізницею, поблизу кордону" ("A.verlotiorum was also found, according to V.V. Protopopova, in Uzhgorod in a flower bed [or small garden] near the railway station; in Chernivtsi Region near the railway not far from the [state] border").That note was added in proof by the editorial team of the Ukrainian Botanical Journal following the personal communication of Prof. Vera V. Protopopova based on observations by and specimens of Protopopova and Myroslav V. Shevera (both from the M.G.Kholodny Institute of Botany).The studied specimens from Transcarpathian Region deposited in KW evidently belong to A. verlotiorum s. str.; however, A. umbrosa was also recently found in Transcarpathia by Shevera (personal communication; Boiko et al., article in preparation).In our opinion, the specimens from Chernivtsi Region available in KW belong to A. umbrosa and because of that the presence of A. verlotiorum s. str. in that region cannot be confirmed yet.However, considering the occurrence of the latter in adjacent countries of Eastern Central Europe, finds of A. verlotiorum in Chernivtsi Region cannot be excluded in the future.In addition to that, A. verlotiorum s. str. is now also reported from Lviv (Mamchur et al., 2017), which is also confirmed by some specimens deposited in KW.However, the morphologically similar species A. umbrosa is also known in Lviv Region (Kuzyarin, 2012) and because of that critical revision of specimens and records of A. verlotiorum and A. umbrosa from the western part of Ukraine is needed, and will be provided in a forthcoming article (Boiko et al., in preparation).

Artemisia verlotiorum in Kyiv
A colony of A. verlotiorum was discovered in Kyiv by Mosyakin on 12 May 2018.The plants were growing in shady places in a lilac garden (syringarium) not far from the entrance of the Syrets Arboretum (Syretskiy Dendropark, Сирецький дендропарк) in the northwestern part of the city.This species was not mentioned in the recent checklists of plants of the arboretum (Glukhova et al., 2016;Shynder et al., 2018).
Another clonal stand of A. verlotiorum was found on 28 May 2018 along the back wall of the administrative building of the arboretum (Fig. 1), where plants were growing in the cracks of asphalt (tarmac) and between the asphalt surface and the brick wall.Growing conditions of this colony suggested that it emerged not from rhizomes/stolons or rhizome fragments but from seeds brought by wind from some other nearby colony.Special surveys in the territory of a nearby abandoned plant nursery revealed a larger colony near destroyed greenhouses and along the road (Fig. 2, 3).Most probably that colony was the source of seeds that produced the two smaller colonies in the Syrets Arboretum, especially the stands along the wall (see above).
Our observations in August-October of 2018 confirmed that in climatic conditions of Kyiv (as  well as elsewhere within its native and introduced range) A. verlotiorum is a very late-flowering species, especially if compared to A. vulgaris s. str.The shoots of A. verlotiorum were rather well developed already in mid-May (see Fig. 1); however, first inflorescences were observed in the Syrets Arboretum in late August, and only in October the plants started to produce seeds.At that time the plants of A. vulgaris growing nearby were fully developed and already abundantly produced ripe seeds since mid-summer.
The plants were growing in ruderal plant communities together with the following common associated species:

Concluding remarks
The actual distribution patterns of Artemisia verlotiorum in Eastern Europe are obscured by earlier misidentifications because that species is morphologically similar to and so easily confused with other taxa of the A. vulgaris aggregate, especially A. umbrosa.As we discussed above, there were also some cases of misidentification of Ukrainian specimens from the continental and peninsular (Crimea) parts of the country.
We expect that A. verlotiorum s. str.will be found in the future in some other regions of Ukraine, especially in parks, botanical gardens, and other similar habitats to which the rhizomes of this species can be brought with soil or plant material.However, occurrence and dispersal of A. verlotiorum along railroads, roads, river valleys, etc., is also possible.