Cytisus ruthenicus Fisch. ex Otto in Allg. Gartenzeit. 12: 347 (1844)

Sennikov, Alexander N. & Tikhomirov, Valery N., 2024, Atlas Florae Europaeae notes, 33. Taxonomic synopsis of East European species of the Cytisus ratisbonensis group (Fabaceae), PhytoKeys 238, pp. 157-197 : 157

1. Cytisus ruthenicus Fisch. ex Otto in Allg. Gartenzeit. 12: 347 (1844)

- Cytisus ratisbonensis subsp. ruthenicus (Fisch. ex Otto) Syr. in Trudy Bot. Sada Imp. Yur’evsk. Univ. 13(1-2): 209 (1912) - Chamaecytisus ruthenicus (Fisch. ex Otto) Klásk. in Preslia 30: 214 (1958) - Chamaecytisus ratisbonensis subsp. ruthenicus (Fisch. ex Otto) Ziel. in Arbor. Kórnickie 20: 78 (1975).

= Cytisus ruthenicus var. zingeri Nenukow in Litvinov, Spisok Rast. Gerb. Russk. Fl. Bot. Muz. Rossiisk. Akad. Nauk 8(52): 1 (1916) - Cytisus zingeri (Nenukow) V.I.Krecz. in Bot. Zhurn. SSSR 25: 260 (1940) - Chamaecytisus zingeri (Nenukow) Klásk. in Preslia 30: 214 (1958). Type. Russia. Nizhni Novgorod Region, Balakhna District. Chernoretsk State Forest District, pine forests on sands, 22.06.1914, I.M. Shvetsov [Herbarium Florae Rossicae No. 2552(pt.)] (lectotype LE01024070, two fragments from the right (with well-developed leaves and pods), designated by Sennikov and Tikhomirov in Sennikov et al. (2021: 58); isolectotypes H1279755, KW000114831, KW000114832, LE01024071, LE01024072, M0210776, MW0593001, NNSU, NS0031789, and many other collections).

= Cytisus ssyreiszczikovii V.I.Krecz. in Bot. Zhurn. SSSR 25: 261 (1940) - Chamaecytisus ruthenicus var. ssyreiszczikovii (V.I.Krecz.) Tzvelev, Fl. Evropeiskoi Chasti SSSR 6: 222 (1987) - Chamaecytisus ssyreiszczikovii (V.I.Krecz.) Vasjukov & Tatanov in Turczaninowia 19: 67 (2016). Type. Russia. Ulianovsk Region and District. Belyi Klyuch Village, mixed forest with oak on the watershed between Volga and Sviyaga Rivers, 02.08.1917, A.P. Shennikov (lectotype LE01017901, designated by Vasjukov and Tatanov (2016: 67)).

= Chamaecytisus pineticola Ivchenko in Ukr. Bot. Zhurn. 49: 84 (1992), syn. nov. Type. Ukraine. "In adjacentibus Kioviae, prope Irpenj, margines pineti," 25.05.1976, I.S. Ivchenko (holotype KW).

Type.

Crimea. "Ex Tauria", P.S. Pallas in Herb. Bieberstein (lectotype LE01043886, designated here). Fig. 2 .

Description.

Upright shrubs with erect stems up to 120(200) cm tall and long branches. Leaves with obovate leaflets, glabrous above, with appressed hairs 0.2-0.4 mm long below, petioles sparsely covered with appressed hairs. Flowers strictly lateral, 1-4 in axils, on pedicels 5-7 mm long, yellow; calyx 10-12 mm long, with appressed hairs 0.4-0.6 mm long; standard suborbicular, glabrous above.

Distribution.

Europe: Poland ( Zieliński 1975; Danielewicz 2020), Moldova ( Heydemann 1986), Belarus ( Semerenko 1999; Dubovik 2016), Ukraine ( Tzvelev 1987; Fedoronchuk 2019, 2022), Crimea ( Yena 2012), Russia (central, southern and south-eastern parts: Tzvelev 1987), Kazakhstan (north-western part: Tulaganova 1981; Abdulina 1999). Asia: Russia (south-western Siberia: Kurbatsky 1994; northern Caucasus: Zernov 2006), Georgia, Kazakhstan (north-western and northern parts: Tulaganova 1981). Apparently, the species is present also in Slovakia ( Holub and Bertová 1988), although the relevant herbarium material has not been revised. Its presence in Hungary and Romania is also expected.

Ecology.

In the forest zone, the species is largely confined to rather dry pine and mixed forests, growing mostly in open places (forest margins and clearings); in the forest steppe and steppe zones, the species is found in open places in forested dry creeks.

Chromosome counts.

2n = 50 ( Parfionaŭ et al. 1975, as Chamaecytisus sp. and C. ruthenicus ); material collected from native populations in Gomel, Grodno and Minsk Regions of Belarus and Zhitomir Region of Ukraine; vouchers at MSK. 2n = 100 ( Semerenko 1984); material collected from native populations in Gomel Region; vouchers at MSK. Dubious record: 2n = 100 ( Forissier 1973, as Chamaecytisus ruthenicus ); material received from the Main Botanical Garden in Moscow, originating from Moscow and Riazan Regions of Russia; vouchers unknown.

Notes on nomenclature.

Cytisus ruthenicus was originally named by F. von Fischer who cultivated plants from the southern course of the Volga River and the southern Ural Mountains in the private botanical garden of Count Alexei Razumovsky. Fischer cultivated rather variable plants received from various collectors, evidently from Friedrich Helm (the Urals) and possibly from Johan Peter Falk (Volga). As evident from herbarium vouchers, subsequently transferred from Gorenki to the Imperial Botanical Garden in St. Petersburg, Fischer introduced the plants from Volga under the provisional name " Cytisus supinus s. volgensis " ( Fischer 1808: 110, 1812: 68). The epithet “ruthenicus” appeared later on herbarium labels and with seeds distributed by Fischer; for the first time, it appeared in print in the first catalogue of plants cultivated in the Botanical Garden in Petersburg ( Fischer 1824: 25). Since then, it was mentioned in a number of publications, all without any descriptive matter.

Wołoszczak (1886) has been commonly cited as the place of valid publication of C. ruthenicus , also by those who published new nomenclatural combinations based on this species name. The material used and distributed by Wołoszczak ( Kerner 1893) largely belongs to C. cinereus , with a minor admixture of C. ruthenicus . Nevertheless, the species name was validly published earlier ( Otto 1844) with a sole reference to an extensive description under C. supinus M.Bieb. non L. ( Marschall von Bieberstein 1819), which is referable to the same plants as intended by Fischer.

Under C. supinus , Marschall von Bieberstein (1819: 476) described plants with foliose inflorescences and appressed pubescence on calyces and pedicels, and hairy pods. He discussed Fischer’s plants named " Cytisus supinus s. volgensis " as a variety of his species. In the personal collection of Bieberstein at LE, there is a specimen labelled " C. supinus " and collected from “Tauria” (Crimea), which is in complete agreement with the characters stated by Bieberstein and represents a typical specimen of C. ruthenicus as currently understood ( Tzvelev 1987). This specimen is designated as a lectotype of C. ruthenicus here.

In spite of the change in the presumed basionym, all combinations published without references to the actual basionym or explicitly based on C. ruthenicus "Fisch. ex Woł.” are validly published as based on C. ruthenicus Fisch. ex Otto under Art. 41.4 and 41.8(a).

Notes on taxonomy and distribution.

The name Cytisus zingeri belongs to a variety with completely glabrous pods, branches and leaves, which is known from several localities at the confluence of Oka and Volga Rivers in Nizhni Novgorod and Vladimir Regions and in two localities in Kurgan Region ( Sennikov et al. 2021). This variety has no separate distribution area, commonly co-occurs with the hairy plants at the same locality ( Nenukow 1916), and plants with intermediate characters are common.

Cytisus ssyreiszczikovii was described as a presumed hybrid between C. ruthenicus and C. zingeri ; in our circumscription, such less hairy plants clearly fall within the variability of the species.

Cytisus ruthenicus was frequently confused with C. ratisbonensis because of their leaves glabrous above; it differs from the latter by upright, taller stems and a longer pubescence on young shoots, petioles and calyces. Cytisus ruthenicus has not been formally reported from Romania, but apparently passed under the misapplied name C. ratisbonensis var. biflorus in Grinţescu (1957).

Similarly, its presence of Slovakia was implied by Holub and Bertová (1988), who noted the occurrence of taller plants in the eastern part of the country.

In the Caucasus, C. ruthenicus was included in C. caucasicus ( Grossheim 1952; Gvinianidze 1981), which was synonymised with C. ruthenicus by Tzvelev (1987). Cytisus caucasicus was described as different from C. ruthenicus in a greater pubescence of the plant, which is less appressed and longer than in the latter species ( Grossheim and Schischkin 1928). Our revision of herbarium collections confirms a broad distribution of C. ruthenicus in the Caucasus and its separation from C. caucasicus .

Chamaecytisus pineticola was distinguished from C. ruthenicus by its occurrence in Ukrainian pine forests rather than Russian steppes and by presumed differences in the density of pubescence and flower size ( Ivchenko and Shevera 1992). As evident from the protologue, the authors misapplied the name C. ruthenicus to C. cinereus , because the collections distributed by Wołoszczak under C. ruthenicus belong to C. cinereus , and their comparisons are, therefore, incorrect. Besides, the authors compared their new species with C. borysthenicus , which was presumably different in a denser pubescence, broader leaflets and nearly glabrous standard. The scattered pubescence on the upper side of its lanceolate leaflets indicated in the protologue ( Ivchenko and Shevera 1992) corresponds to the hybrid between C. borysthenicus and C. ruthenicus , which is quite common along the Dnepr River, but authentic specimens from the type population (KW) undoubtedly belong to C. ruthenicus s. str.

Figures

Figure 2. Lectotype of Cytisus ruthenicus Fisch. ex Otto.