Xanthium orientale L. 1763

Sennikov, Alexander N. & Lazkov, Georgy A., 2021, The first checklist of alien vascular plants of Kyrgyzstan, with new records and critical evaluation of earlier data. Contribution 1, Biodiversity Data Journal 9, pp. 75590-75590 : 75590

Xanthium orientale L. 1763

Xanthium orientale L., Sp. Pl., ed. 2, 2: 1400 (1763).

Xanthium orientale Xanthium italicum Xanthium strumarium subsp. italicum Xanthium orientale subsp. italicum

Xanthium orientale Xanthium brasilicum

Xanthium orientale Xanthium californicum Xanthium orientale subsp. californicum

Xanthium orientale Xanthium albinum Xanthium riparium var. albinum

Diagnosis

This species is characterised by unarmed leaves and narrowly cylindrical hairy burrs 2-3 cm long with numerous, closely spaced hooked prickles.

Distribution

Native distribution

This species is native to North America and South America ( Löve and Dansereau 1959).

Secondary distribution

Neophyte in Europe, Mediterranean, South Africa, Western, Boreal, Central and Tropical Asia, Australia.

In arid regions of Asia, the species was known from several localities in Iran already 40 years ago ( Dittrich 1989). In China, it was recorded for the first time in Beijing in 1991 (as X. italicum : Xu et al. 2012). In Russian Asia, it is known from many localities in southern Siberia ( Khanminchun 1998) and the southern Far East ( Kozhevnikov and Kozhevnikova 2011).

Distribution in Central Asia

Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan.

In Kazakhstan (as X. albinum : Ebel and Ebel 2003), it was first found as ruderal in Tekeli Town (Almaty Region; Dzungarian Alatau), Öskemen [Ust-Kamenogorsk] Town and north-west of Semei Town (East Kazakhstan Region; Altay Mts.); the first record (specimen dated 1955) was registered near Semei Town. Its latest records from the lowland parts of the country ( Qarağandy Region, Aqtoğai District, riversides and ruderal places; Pavlodar Region, Ekіbastūz Town, ruderal places; Túrkistan, Qyzylorda and East Kazakhstan Regions) indicate a greater distribution (as X. albinum : Nobis et al. 2015, Ebel et al. 2016, Plantarium 2021).

In Tajikistan (as X. californicum : Kinzikaeva 1988, Nabiev 1993), the species was recorded as a ruderal from two places, at Zafarobod Town and Dushanbe City.

In Uzbekistan (as X. californicum : Nabiev 1993; as X. albinum : Esanov 2016), the species was known as a weed in Tashkent (first record dated 1986) and as widely naturalised on cotton fields, fallow fields and roadsides of the Buxaro Agricultural Oasis (first recorded in 2007 but apparently established long before). Further records ( Plantarium 2021) suggest its broad distribution in the Fergana Depression. The high impact of the species on cotton fields in Uzbekistan ( Esanov 2016) agrees with the reports from the USA ( Weaver and Lechowicz 1983), but a diversity of Central Asian reports from ruderal habitats suggests its multiple introductions not limited to the cotton cultivation.

Formally reported for the first time from Kyrgyzstan here.

The first record of the species from Central Asia (dated 1955) seems to be linked with the infamous Virgin Lands campaign, which started in 1954 as the extensive cultivation of previously uncultivated lands in northern Kazakhstan. To increase the yield of wheat crops, quality seed of productive varieties of American origin seem to have been partly used.

The large-scale invasion of X. orientale , however, occurred later, in the 1960s, when the extensive import of North American (largely Canadian) grain (wheat and maize) started to compensate for the shortage of domestic grain and fodder ( Chistyakov 2009, FAO 2021).

Distribution in Kyrgyzstan

Western Tian-Shan, Northern Tian-Shan, Alay-Turkestan (Fig. 8 ).

In Kyrgyzstan, this species was rather neglected. Deza (1983) clearly distinguished it from the typical X. strumarium L. and stated that it was found most commonly in (but not restricted to) the Chü Depression, where it occurred along roadsides and irrigation ditches, in populated places, on fallow fields and field margins, in gardens and on cultivated fields. Deza (1983) misapplied the name X. sibiricum Patr. ex Widder, which she seemingly borrowed from Smolianinova (1959) through Gorbunova (1965), to this species in spite of their contrasting morphology, thus assuming its native distribution area stretching from Siberia to Central Asia. Due to this incorrect nomenclature, the species was omitted from the recent checklist of the flora of Kyrgyzstan ( Lazkov and Sultanova 2011, Lazkov and Sultanova 2014).

According to herbarium collections, X. orientale occurs in a number of localities in or around the Chü, Ysyk-Köl and Fergana Depressions, climbing into the mountains as high as 2200 m and as far as 30 km from the depressions with their high levels of agricultural activity and human population density. Our field observations confirm its currently extensive dispersal (Fig. 9 ).

Ecology

Gravelly riversides in the native distribution area; disturbed grounds, gravelly roadsides, sandy and gravelly riversides, fallow fields in the secondary distribution area.

Biology

Annual.

Notes

The modern taxonomic concept in Xanthium and the correct name for this species were established by Greuter (2003) and Tomasello (2018). Our understanding of the diagnostic characters is based on our revision of historical collections and field observations and agrees with the treatment of Nabiev (1993).

The burrs in Central Asian plants are narrowly cylindrical, thus corresponding to X. orientale subsp. californicum (Greene) Greuter (incl. X. chinense Mill.), as originally identified by Kinzikaeva (1988).

Introduction to Kyrgyzstan

Period of introduction

Neophyte.

The first collection from Kyrgyzstan (Suzak Town) is dated 1968. We assume that the species had arrived after the Second World War, in the 1960s, as a contaminant of wheat grain of North American origin.

Pathways of introduction

Transport - Contaminant: Seed contaminant.

Most likely, the species had arrived as a contaminant of wheat imported from Canada, in agreement with observations in Europe (e.g. Suominen 1979). In Australia, contamination of cotton seed and animal fur were reported as other main pathways of introduction ( McMillan 1975).

Further dispersal occurred with domestic animals, water and transport.

Invasion status

Fully naturalised, highly invasive.

Judging from the tendencies in its distribution and expansion, Xanthium orientale seems to be more adapted to the hot arid climate and may have a better prospect of naturalisation than its predecessor, X. strumarium .

Evidence of impact

Agriculture - major impact (abundant weed of fields, gardens and pastures, contamination of wool). Native ecosystems - major impact (local occurrence along mountain streams and roadsides in mountainous areas, forming extensive monodominant stands). Urban areas - major impact (ruderal occurrence, locally abundant).

Trend

Rapidly increasing (observed).

Figures

Figure 8. Distribution of Xanthium orientale in Kyrgyzstan according to herbarium specimens and our observations.

Figure 9. Xanthium orientale along the Kyzyl-Suu River, Kyrgyzstan (photo by G. Lazkov, 19 August 2021).