Hesperis pycnotricha Borbás & Degen, 1902

Sennikov, Alexander, Lazkov, Georgy & German, Dmitry A., 2025, The first checklist of alien vascular plants of Kyrgyzstan, with new records and critical evaluation of earlier data. Contribution 3, Biodiversity Data Journal 13, pp. e 145624-e 145624 : e145624-

Hesperis pycnotricha Borbás & Degen, 1902

Hesperis pycnotricha Borbás & Degen , Magyar Bot. Lapok 1: 269 (1902).

— Hesperis matronalis auct. non L.: Deza (1989), Lazkov and Sultanova (2011), Lazkov and Sultanova (2014).

It is commonly believed ( IPNI 2024) that the species name Hesperis pycnotricha was validly publised in 1903, when the species was described in full and in Latin language ( Borbás 1903, p. 17). Its correct nomenclatural citation was provided by Kotov (1979), who noted that the conditions for valid publication (species diagnosis in Hungarian language, in an identification key) were fulfilled earlier, in a preceding part of the same article ( Borbás 1902, p. 269).

Distribution

Native distribution

The species distribution covers south-eastern Europe ( Bulgaria), southern part of Eastern Europe (including the neighbouring parts of Slovakia), north-western Caucasus and Asia Minor ( Tzvelev 1959, Kotov 1979, Jalas and Suominen 1994).

Secondary distribution

Europe ( Tzvelev 1959, Jalas and Suominen 1994), Northern Asia ( Chepinoga et al. 2024), North America ( Dorofeev 2013).

The species has been extensively cultivated in Eastern Europe ( Tzvelev 1959, Kotov 1979), Siberia ( Tzvelev 1959) and known as escaping from cultivation in these territories ( Tzvelev 1959, Kotov 1979). Its occurrence in Central Asia remained very obscure until Lazkov et al. (2011) reported an alien record from Kyrgyzstan. Our data suggest that this is the only species of the H. matronalis group that is commonly cultivated in Central Asia.

According to the herbarium specimens cited by Tzvelev (1959), the species has been cultivated in Eastern Europe at least since the mid- 19 th century and found as escaped from cultivation in Siberia (Omsk Town) in 1886. Although it was common in ornamental cultivation already in the 19 th century, its alien occurrence in Siberia has been registered rather recently; to date, in Northern Asia, it is known from Western Siberia and Altai ( Chepinoga et al. 2024).

In North America, the species is most common among the cultivated and alien members of the H. matronalis group, which is widely naturalised in the USA ( Rollins 1981) and occurs in many states of the USA and also in Canada ( Dorofeev 2013).

Distribution in Central Asia

Kazakhstan, Kyrgyzstan, Uzbekistan (Fig. 8 ).

As evident from herbarium collections, the species was cultivated in southern Kazakhstan since the last decades of the 19 th century (" Flora iliensis " = Ili River Basin [most likely Almaty Town], 1886, A. N. Krasnov ( LE)), i. e. from the beginning of its settlement by Russian colonists. The long tradition of ornamental cultivation suggests that the species is present in ruderal habitats. Such occurrences (Fig. 9 ) have been found on online citizen-science platforms ( iNaturalist 2024, Plantarium 2024) and provide evidence for the species naturalisation or long-time persistence in the country. This is the first record of the subspontaneous occurrence of Hesperis pycnotricha in Kazakhstan.

In Uzbekistan, the species is cultivated in populated places, but not considered as running wild ( Sennikov et al. 2020). Its first herbarium collection from cultivation is dated by the 1930 s (Tashkent, in a garden of P. A. Baranov, 19. 06. 1932, A. Lapin ( LE)).

In Kyrgyzstan, Hesperis pycnotricha was reported as being cultivated and occasionally escaped from cultivation under the wrong name H. matronalis ( Deza 1989) . Its later record as new to Kyrgyzstan and Central Asia as a whole ( Lazkov et al. 2011) was the first documented observation of the species dispersal. The occurrence of the species in a spruce forest of the Jety-Ögüz River ravine ( Lazkov et al. 2011) may look strange when considered isolated from the context because it misleadingly hints at the wilderness. The ravine is a popular touristic attraction and a path along the river starts from the sanatorium that is famous for its geothermal springs. The species was apparently dispersed to the wild from flowerbeds in touristic places.

In Tajikistan, the species is apparently cultivated, but we have no documentation of its occurrence.

Distribution in Kyrgyzstan

Northern Tian-Shan (Fig. 10 ).

Ecology

Meadow steppes and true steppes in lowlands and foothills in the native distribution area ( Tzvelev 1959). Ruderal places, roadsides, riversides in the secondary distribution area.

Biology

Biennial plant with a small taproot.

Taxon discussion

The taxonomy of the Hesperis matronalis group largely relies on flower colour and pubescence; species rank is commonly accepted for the main segregate taxa. The following three species are involved in a taxonomic confusion in Central Asia ( Tzvelev 1959, Kotov 1979, Ball 1993).

Hesperis matronalis L. s. str. is a mesophytic species of forest meadows, which is characterised by the pubescence of simple hairs. Its upper leaves are gradually attenuated into a very short petiole. Native distribution: Europe, Caucasus, Asia Minor.

Hesperis pycnotricha is a xerophyte occurring mostly in steppes, which has a dominant pubescence of short branched hairs, sometimes with scattered short simple hairs. Its upper leaves are sessile, slightly amplexicaul. Native distribution: centred around the Black Sea.

Hesperis sibirica L. is a mesophyte largely associated with coniferous forests, with dominant simple hairs and a glandular pubescence in the inflorescence (sometimes covering the whole plant). Its upper leaves are sessile, sometimes auriculate. Native distribution: Central Asia, Northern Asia (including parts of Mongolia and China).

The pubescence type and the shape of leaves clearly discriminate the three taxa and their different native distribution areas and ecological preferences confirm the distinction. Hesperis matronalis and H. pycnotricha were commonly treated as a single species in the past, but that confusion has survived until recent times in non-taxonomic literature (e. g. Deza (1989)) and some taxonomic databases (e. g. POWO (2024)).

The taxonomic distinction among these three taxa allows us to separate native ( H. sibirica ) and non-native ( H. pycnotricha ) occurrences of the H. matronalis group in Central Asia. Surprisingly, H. matronalis s. str. is completely absent from the Central Asian herbarium collections and documented observations. Its previous reports from the local cultivation (e. g. Deza (1989), iNaturalist (2024), Plantarium (2024)) are based on the broad species treatment and should be interpreted as belonging to H. matronalis s. l. According to our examination, the actual material identified as H. matronalis belongs exclusively to H. pycnotricha . For this reason, H. matronalis s. str. should be excluded from the flora of Central Asia.

Notes

The flower colour varies noticeably within the species. The most common variety has pink flowers, whereas a darker, pinkish-violet flower variant can also be found ( Tzvelev 1959, Kotov 1979, iNaturalist 2024).

Introduction to Kyrgyzstan

Period of introduction

Neophyte.

The species was introduced most likely during the same period as in Uzbekistan and Kazakhstan, i. e. the last quarter of the 19 th century, due to the common market of garden cultivation in the Russian Empire. The beginning of its running wild is uncertain, but ruderal occurrence is highly likely from the beginning of cultivation.

The first published observation of its alien status belongs to the 1980 s ( Deza 1989) and the first observation in native habitats is dated 2009 ( Lazkov et al. 2011).

Pathways of introduction

Escape from confinement: Ornamental purpose other than horticulture.

The plants were cultivated outdoors for ornamental purposes and run wild from the places of cultivation.

Seed dispersal on human feet is a likely vector of the secondary dispersal, as the species is often observed growing along pedestrian paths.

Source of introduction

Eastern Europe.

The species has been repeatedly introduced via the ornamental seed supply of the Russian Empire and the USSR.

Invasion status

Casual.

The ruderal occurrences of the species in Kyrgyzstan ( Deza 1989) should be casual as no such naturalisation is currently known. The species status in a single locality recorded in the Teskey Alatoo ( Lazkov et al. 2011) is unknown as the locality description is unavailable. We prefer to treat the species status as casual ( Sennikov and Lazkov 2024 a) until naturalised populations or at least persisting colonies are known.

Evidence of impact

Agriculture - no impact (not recorded in crop production areas). Native ecosystems - minor impact (once recorded in recreation forest areas, may be found elsewhere outside populated places). Urban areas - minor impact (sometimes escapes and occurs in ruderal places).

Trend

Slowly increasing (inferred).

The species has long been highly popular in ornamental cultivation. Its wide use for flower beds and in private gardens constantly increases the risk of unintentional introduction. Further discoveries of locally persisting or even naturalised populations are expected, as evident from the current expansion of the species in Siberia ( Ebel 2002).

Figures

Figure 8. Cultivation and subspontaneous occurrence of Hesperis pycnotricha in Central Asia according to the specimens examined and documented observations (iNaturalist 2024, Plantarium 2024).

Figure 9. A ruderal occurrence of Hesperis pycnotricha (pink flower variant) in Karagandy Town, Kazakhstan (photo by I. Evdokimov, 13 May 2020). Source: https://www.plantarium.ru/page/image/id/656303.html, misidentified as H. matronalis (Plantarium 2024).

Figure 10. The subspontaneous record of Hesperis pycnotricha in Kyrgyzstan according to the specimen examined.