Research Article |
Corresponding author: Alexander N. Sennikov ( alexander.sennikov@helsinki.fi ) Academic editor: Alexander Sukhorukov
© 2024 Alexander N. Sennikov, Valery N. Tikhomirov.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Sennikov AN, Tikhomirov VN (2024) Atlas Florae Europaeae notes, 33. Taxonomic synopsis of East European species of the Cytisus ratisbonensis group (Fabaceae). PhytoKeys 238: 157-197. https://doi.org/10.3897/phytokeys.238.118031
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A group of species of Cytisus sect. Tubocytisus with strictly lateral inflorescences, commonly referred to as C. ratisbonensis s.l., is critically revised in Eastern Europe on the basis of morphology and comprehensive treatment of herbarium specimens and observations. Seven species and two presumed hybrids are recognised. Complete accounts are provided for each species, with synonyms, typifications, brief morphological descriptions, data on ecology and distributions, taxonomic and nomenclatural annotations. Cytisus polonicus is described as new to science, separated from C. ratisbonensis on the basis of morphology and diploid (vs. tetraploid) chromosome count. The lectotype of C. elongatus is superseded and a new lectotype is designated; this name has priority for the species previously known as C. triflorus. Six species names are newly placed to the synonymy: Chamaecytisus pineticola under Cytisus ruthenicus s. str., and Cytisus czerniaevii, C. leucotrichus, C. lindemannii, C. ponomarjovii and Chamaecytisus korabensis under Cytisus elongatus. The presumed hybrid between C. ruthenicus and C. elongatus, which was incorrectly known as C. czerniaevii, is described here as C. semerenkoanus. Cytisus lithuanicus, which has been an obscure name since its original publication, is resurrected for a newly-recognised octoploid species, which is endemic to eastern Poland, western Belarus and north-western Ukraine. The name C. cinereus is re-instated for the species previously known as C. paczoskii, and C. horniflorus is added to its synonymy; its complete distribution area is circumscribed, and its occurrence in Austria, Poland, Romania, Serbia and Slovakia is documented. Cytisus kreczetoviczii and C. elongatus are reported for the first time from Belarus, and the latter species also from Bosnia and Herzegovina, Montenegro and Slovenia. Cytisus borysthenicus and C. elongatus are reported as new to some territories in European Russia. Cytisus ratisbonensis s. str. is treated as absent from Eastern Europe. The neglected protologue of C. ruthenicus is discovered, and the nomenclature of all other names is verified and corrected when necessary. The original material of C. borysthenicus is re-discovered. Five further lectotypes and one neotype are designated. Distribution areas are circumscribed on the basis of numerous herbarium collections and documented observations, identified or verified by the authors. Chromosome counts published for nameless taxa from Belarus, Ukraine and Russia are assigned to the species according to their herbarium vouchers: C. borysthenicus, C. kreczetoviczii and C. lithuanicus are octoploid (2n = 100), C. ruthenicus is tetraploid (2n = 50) and octoploid (2n = 100), and C. semerenkoanus and C. elongatus are tetraploid (2n = 50).
Belarus, Chamaecytisus, chromosome counts, Leguminosae, mapping, nomenclature, Russia, typification, Ukraine
A group of Cytisus (Cytiseae, Fabaceae) with a tubular calyx (C. sect. Tubocytisus DC., Chamaecytisus Link) was often treated as a separate genus (
The taxonomic concept in Cytisus sect. Tubocytisus had changed dramatically with time. In Eastern Europe, only one or very few species with strictly lateral inflorescences were recognised in the 19th century.
Outside Eastern Europe, these species were treated in some critical revisions. In Poland,
Despite recent attempts of further taxonomic splitting (e.g.
These taxonomic contradictions and a certain disorder in herbarium collections obscured the taxonomy and distribution of East European species of Cytisus sect. Tubocytisus with lateral inflorescences, which, according to different sources, may be known as C. ratisbonensis Schaeff., C. hirsutus L., C. ruthenicus or a number of narrowly and variously defined species. In connection with mapping of this group for Atlas Florae Europaeae, we decided to revise the taxonomy, nomenclature and distributions of its taxa, based on our exhaustive examination of major herbarium collections and literature.
In this particular paper, we examined the taxonomic limits and the species composition of the C. ratisbonensis group, which is generally characterised by appressed to subpatent hairs which are densely covering calyces, pedicels, petioles and young branches, and the flowers collected in long racemes of abbreviated axillary fascicles. These characters are widely accepted in the main taxonomic literature (
This taxonomic revision used a traditional, morphology-based approach. Diagnostic characters were re-evaluated taking into account the variability observed in herbarium specimens. Taxonomic entities with stable diagnostic characters and certain distribution areas were recognised at species rank, whereas their morphologically intermediate forms found in and around the zone of co-occurrence were treated as presumably hybridogeneous species. Morphological descriptions were compiled on the basis of herbarium specimens and literature. An original identification key and a comparative table were constructed on the basis of these characters.
Distributional areas were revised on the basis of available herbarium collections and documented observations, and taxonomic treatments and checklists were critically evaluated in order to avoid conflicting identifications. Accepted and rejected country-level records are listed in the text under species distribution data; administrative territories or regions are detailed for larger countries. Europe is defined as in Atlas Florae Europaeae (e.g.
Herbarium specimens were revised de visu or as scanned images via JSTOR (https://www.jstor.org), JACQ Virtual Herbaria (https://www.jacq.org), Muséum national d’Histoire naturelle (https://science.mnhn.fr) and Hungaricana (https://gallery.hungaricana.hu/en/Herbarium); these data were complemented with observations documented by photographs which were available online via iNaturalist (https://www.inaturalist.org/). A complete description of the resulting dataset (3699 specimens or observations) with point distribution maps is published elsewhere (
All available literature were consulted for nomenclatural novelties and distributional records relevant to Cytisus in Eastern Europe. Protologues were analysed, original material and type designations were assessed according to the nomenclatural Code (
As an important biological character supporting the species delimitations, chromosome counts available from Eastern Europe were examined on the basis of published literature (
The diagnostic characters were extensively discussed by
Species | Stems | Branching pattern | Leaflets, shape | Leaflets, pubescence above | Calyx, length (mm) | Calyx, pubescence |
---|---|---|---|---|---|---|
Cytisus borysthenicus | erect, up to 120(200) cm tall | basal | lanceolate | densely and evenly hairy | 10–12 | appressed, 0.4–0.6 mm |
Cytisus cinereus | erect, basally ascending, up to 40–60(80) cm tall | basal | elliptic to obovate | glabrous | 11–14 | laxly appressed to subpatent, 0.6–1.2(1.5) mm |
Cytisus kreczetoviczii | erect, up to 80 cm tall | basal | lanceolate to elliptic | sparsely hairy | 10–12 | (laxly) appressed, 0.4–0.6(0.8) mm |
Cytisus lithuanicus | erect, basally prostrate, up to 40(60) cm tall | diffuse | obovate | glabrous | 12–14 | laxly appressed, 0.6–0.8 mm |
Cytisus polonicus | prostrate, up to 20 cm above ground | basal | obovate to elliptic | glabrous | (7)8–10 | (laxly) appressed, 0.6–0.8(1) mm |
Cytisus ratisbonensis | prostrate, up to 20 cm above ground | basal | obovate to elliptic | glabrous | 11–14 | laxly appressed, 0.8–1.2(1.6) mm |
Cytisus ruthenicus | erect, up to 120(200) cm tall | basal | obovate | glabrous | 10–12 | appressed, 0.4–0.6 mm (or absent) |
Cytisus semerenkoanus | erect, basally ascending, up to 60(80) cm tall | basal | elliptic to obovate | sparsely hairy to subglabrous | 10–12 | appressed and subpatent, 0.4–0.9 mm |
Cytisus elongatus | erect, basally ascending, up to 40–60(80) cm tall | basal | elliptic to obovate | densely hairy | 11–12 | subpatent, 0.8–1.2 mm |
Cytisus wulffii | prostrate, up to 20 cm above ground | diffuse | obovate to oblong | hairy | 14–15 | laxly appressed, 0.5–1 mm |
All species are shrubs of small or medium size with lignified stems, typically with no main trunk, which differ in growth type and branching pattern of their twigs.
Some species (C. polonicus Sennikov & Val.N.Tikhom., C. ratisbonensis, C. wulffii) have main stems which are predisposed for prostration, thus forming horizontally growing, apically ascending branches. Such prostrate shrubs grow over rocky grounds in mountainous areas.
The other species with generally erect stems can be classified according to the length of ascending basal parts of their main stems, forming compact or lax shrubs. Cytisus borysthenicus and C. ruthenicus have basally suberect stems and very little tendency to ascending. Cytisus cinereus Host and C. elongatus Waldst. & Kit. have basally ascending stems that run shortly underground, thus forming lax shrubs. The main stems in C. lithuanicus Gilib. are long ascending; when their basal parts are covered by soil, they may produce adventitious nodal roots, with a large part of the shrub thus being underground; this type of shrub is transitional to prostrate.
The branching pattern of stems may be basal (C. borysthenicus, C. cinereus, C. elongatus, C. polonicus, C. ratisbonensis, C. ruthenicus) with rather long and thick branches, or diffuse (C. lithuanicus, C. wulffii) with shorter and thinner branches.
The plant height differs considerably. The prostrate shrubs (C. polonicus, C. ratisbonensis, C. wulffii) ascend up to 20 cm above the ground. The compact erect shrubs (C. borysthenicus, C. ruthenicus) may grow very robust, up to 150 cm tall, whereas the lax erect shrubs (C. cinereus, C. elongatus) are typically lower, up to 60(80) cm tall. The semi-prostrate shrubs (C. lithuanicus) are up to 40(60) cm tall.
This revision is limited to the species with a single type of inflorescence, i.e. lateral. Flowers are collected in small axillary fascicles, which are borne on lignified twigs of the previous year; flowering occurs in late summer. As a rule, no flowers are borne on the new growth of twigs. Exceptions are extremely uncommon; we have seen only one specimen of C. cinereus that abnormally developed apical inflorescences on the new growth in secondary flowering.
Flowers are pedicellate, pedicels of various lengths. There is a tendency for certain species to produce longer (C. lithuanicus) or shorter (C. polonicus) pedicels, but this character is too variable and cannot be reliably used as diagnostic because the pedicel length depends on the flowering period and ecological conditions.
Corolla is of various shades of yellow (
Leaves are composite, of three leaflets which are mostly obovate to nearly elliptic in most species, except C. borysthenicus in which the leaflets are lanceolate or narrowly lanceolate. The leaflets are invariably glabrous or hairy above, except for presumed hybrids, in which the leaflets can be variously hairy to subglabrous. This character is easy to observe and clearly diagnostic.
Pubescence is a key character that distinguishes taxa at the level of species, especially in East European treatments (
The type of pubescence on young branches, pedicels and calyces is most characteristic of certain species (Fig.
There are very few reports on chromosome numbers in Cytisus sect. Tubocytisus from Eastern Europe. In those cases when vouchers were traced, this information proved to be informative and taxonomically valuable.
Based on the combination of the chromosome counts and morphology,
In the absence of taxonomic expertise,
Similarly, we decipher the following chromosome counts included in
Hybridisation and polyploid formation were a key factor in evolution of plant taxonomic diversity (
Herbarium specimens of C. kreczetoviczii are observed to have lower seed set, which may indicate partial hybrid sterility. However, no experimental studies have been performed to prove this observation.
–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
=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
=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).
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.
Europe: Poland (
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.
2n = 50 (
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” (
Under C. supinus,
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).
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 (
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
Similarly, its presence of Slovakia was implied by
In the Caucasus, C. ruthenicus was included in 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 (
–Chamaecytisus kreczetoviczii (Wissjul.) Holub in Folia Geobot. Phytotax. 11: 83 (1976) – Chamaecytisus ruthenicus var. kreczetoviczii (Wissjul.) Skalická in Rad. Akad. Nauka Um. Bosne Hercegovine 72: 241 (1983) – Cytisus ruthenicus subsp. kreczetoviczii (Wissjul.) Cristof. in Webbia 45: 214 (1991).
Ukraine. “Prope flum. Gruzkyj Jelanczyk, loco Charcysska balka dicto, in decliviis calcareis sarmaticis,” 23.05.1926, Yu.D. Kleopov (lectotype KW000022339, designated by
Upright shrubs with erect stems up to 80 cm tall and long branches. Leaves with lanceolate to elliptic leaflets, sparsely hairy above, with appressed hairs 0.1–0.2(0.4) mm long below, petioles sparsely covered with laxly appressed (partly subpatent) hairs. Flowers strictly lateral, 1–4 in axils, on pedicels 4–6 mm long, yellow; calyx 10–12 mm long, with (laxly) appressed hairs 0.4–0.6(0.8) mm long; standard suborbicular, glabrous or sparsely hairy above.
Europe: Belarus (new record), Ukraine, Russia (
Alluvial sands in larger river valleys, riverside slopes, often on exposed calcareous substrates.
2n = 100 (
The type specimen of Cytisus kreczetoviczii was interpreted as holotype by
This is a variable taxon, which occupies an intermediate position between C. borysthenicus and C. ruthenicus in the shape of leaves and the pubescence of the upper side of leaves. Taxonomically, these plants were recognised as a locally endemic species in Ukraine (
–Cytisus biflorus subsp. borysthenicus (Gruner) Pacz. in Trudy Bot. Sada Imp. Yur’evsk. Univ. 15(2–3): 95 (1914) – Chamaecytisus borysthenicus (Gruner) Klásk. in Preslia 30: 214 (1958) – Chamaecytisus biflorus subsp. borysthenicus (Gruner) Elenevsky & Radygina in Elenevsky et al., Rast. Saratov. Pravober.: 41 (2000).
Upright shrubs with erect stems up to 120(200) cm tall and long branches. Leaves with lanceolate leaflets, densely and evenly hairy above, with dense appressed hairs 0.1–0.2(0.3) mm long below, petioles densely covered with appressed hairs. Flowers strictly lateral, 1–4 in axils, on pedicels 2–5 mm long, yellow; calyx 10–12 mm long, with appressed hairs 0.4–0.6 mm long; standard suborbicular, hairy above.
Europe: Ukraine, Crimea (
Alluvial sands in larger river valleys, sandy steppes, open sands, sparse pine forests on sands, mostly along rivers.
2n = 100 (
Leopold Gruner (
Herbarium collections of Leopold Gruner are known at LE and MW (
As a matter of surprise, one specimen representing Gruner’s collection of Cuscuta monogyna, with Cytisus borysthenicus as a host plant, has recently resurfaced at MW. This specimen was clearly associated by Gruner with the protologue of C. borysthenicus and is, therefore, part of the original material of the latter name. Although the fragment of C. borysthenicus on this specimen is a sterile branch densely covered by a parasite, it is perfectly adequate to identify the species and may serve as lectotype.
The original description of C. borysthenicus is ambiguous. The ecology (sandy hills) and the hairy standard indicate this species as currently understood, whereas the obovate-lanceolate leaves, glabrous above, clearly refer to C. ruthenicus. This discrepancy was neglected by
So far, the original material of C. borysthenicus, which is taxonomically referable to C. ruthenicus, has not been found. Gruner’s specimen of Cuscuta monogyna on Cytisus borysthenicus apparently belongs to the species as established by
This species is largely confined to the systems of southern East European rivers and was probably dispersed with sand deposits. Its distribution extends much further north-east and north-west than was indicated by
The species name is given in honour of Larisa Vasilievna Semerenko (
Upright shrubs with erect, basally ascending stems up to 60(80) cm tall and long branches. Leaves with elliptic to obovate leaflets, sparsely hairy to subglabrous above, with lax hairs 0.2–0.6 mm long below, petioles sparsely covered with appressed and subpatent hairs. Flowers strictly lateral, 1–4 in axils, on pedicels 3–6 mm long, yellow; calyx 10–12 mm long, with appressed and subpatent hairs 0.4–0.9 mm long; standard suborbicular, hairy to subglabrous above.
Europe: Poland, Moldova, Belarus, Ukraine, Russia. Asia: Russia (Caucasus), Abkhazia.
In the forest zone, this taxon is found in dry forests on rich soils (oak forests and mixed broadleaved-pine forests with steppe plants), mostly in open places; in the forest steppe and steppe zones, it occurs in sparse forests and open steppe-like places.
2n = 50 (
–Chamaecytisus elongatus (Waldst. & Kit.) Link, Handbuch 2: 155 (1831) – Cytisus hirsutus subsp. elongatus (Waldst. et Kit.) Briq., Etud. Cytis. Alp. Marit.: 168 (1894) – Chamaecytisus ciliatus subsp. elongatus (Waldst. & Kit.) Soó in Feddes Repert. 85: 439 (1974) – Chamaecytisus glaber var. elongatus (Waldst. & Kit.) Kuzmanov in Jordanov, Fl. Narodna Republ. Bulg. 6: 86 (1976).
=Cytisus leucotrichus Schur in Oesterr. Bot. Z. 10: 179 (1860), syn. nov. – Chamaecytisus leucotrichus (Schur) Czerep., Sosud. Rast. SSSR: 229 (1981) – Chamaecytisus triflorus subsp. leucotrichus (Schur) Holub in Bertová, Fl. Slovenska 4(4): 35 (1988). Type. Romania. “Rothen Berg bei Mühlbach [Sebeș]”, [05].07.1853, F. Schur (lectotype LW00205768, designated by
=Cytisus lindemannii V.I.Krecz. in Bot. Zhurn. SSSR 25: 259 (1940), syn. nov. – Chamaecytisus lindemannii (V.I.Krecz.) Klásk. in Preslia 30: 214 (1958). Type. Ukraine. “Elisabethgrad” [Kropyvnytskyi], 06.05.1873, E. Lindemann (holotype LE01024081; isotype LE01024082). Fig.
=Cytisus czerniaevii V.I.Krecz. in Bot. Zhurn. SSSR 25: 261 (1940), syn. nov. – Chamaecytisus czerniaevii (V.I.Krecz.) Tzvelev, Fl. Evropeiskoi Chasti SSSR 6: 223 (1987). Type. Ukraine. Kharkov Region, Zmiev District, Hamlet of Fedorchenko, 24.04.1910, G.I. Širjaev (lectotype KW000114840, designated here). Other original material. Ukraine. Kharkov Region: Steppes near Chuguev, 19.05.1852, V.M. Cherniaev (KW). Sumy Region, Lebedin District, “prope Grun, in steppis princ. Kapnist” [near Grun’, in steppes of Count Kapnist = ‘Mikhailovskaya Tselina’ Nature Reserve], 09.06.1905, G.I. Širjaev (KW000114839).
=Cytisus ponomarjovii Seredin in Novosti Sist. Vyssh. Rast. 13: 192 (1976), syn. nov. – Chamaecytisus ponomarjovii (Seredin) Czerep., Sosud. Rast. SSSR: 229 (1981). Type. Russia. Krasnodar Territory, Tuapse District, 1 km NW of Dzhubga Village, oak forest, 08.07.1973, R.M. Seredin (holotype LE).
=Chamaecytisus korabensis Pifkó & Barina in Stud. Bot. Hung. 47(1): 164 (2016), syn. nov. Type. Albania. Qarku i Dibrës: [Korab-Koritnik Nature Park,] Mali i Bardhë Mts, near peak Maja e Pelpenikut, above village Sllatinë, on evaporites, 41.78419°N, 20.45978°E, 1928 m, 17.06.2013, Z. Barina & D. Pifkó 22354 (holotype BP759110; isotype BP759111).
Romania. Historical Banat Region: “In sylvis Beregh, Banaticis et Croaticis”, 1800, P. Kitaibel (lectotype W20030003241, left-hand fragment, designated here: https://w.jacq.org/W20030003241). Possibly Ukraine. [“In comitatis Bereghensis” = Bereg County, “in sylvis”,] Herb. Waldstein (superseded lectotype PR155757/738a, designated by
Upright shrubs with erect, basally ascending stems up to 40–60(80) cm tall and long branches. Leaves with elliptic to obovate leaflets, densely hairy above, with lax hairs 0.4–0.8 mm long below, petioles rather densely covered with laxly appressed to subpatent hairs. Flowers strictly lateral, 1–4 in axils, on pedicels 2–4 mm long, yellow; calyx 11–12 mm long, with subpatent hairs 0.8–1.2 mm long; standard suborbicular, glabrous or hairy above.
Europe: France (along the valley of Rhône:
In the forest zone, this species occurs in sparse forest stands and on forest margins with steppe herbaceous species, mostly in xerophilous oak forests, at elevations below 500(700) m; in the forest steppe and steppe zones, it is found among sparse shrubs in dry creeks, steppe-like meadows and steppes. It also occurs in oak forests and steppe-like meadows in the mountains.
2n = 50 (
Cytisus elongatus was described from present-day Romania (Caraş-Severin, Banat) and Ukraine (former Bereg County) (
According to the published diaries of P. Kitaibel (
After the protologue of C. elongatus was published, Kitaibel collected further specimens of this species (
In search for the other original material, we examined online collections of B, BP, PRC and W. Specimens in Herbarium Willdenow at B, which are labelled “Hungaria”, are likely original material because Willdenow received manuscripts and specimens from Waldstein and Kitaibel, of which hundreds are currently kept in Berlin (
The most important specimen was found at W (W 20030003241). The plants on this sheet were identified as C. elongatus with a reference to the protologue; the label of this specimen written by Kitaibel is composite and reads “In sylvis Beregh, Banaticis et Croaticis”. This label reflects Kitaibel’s travels to Banat in 1800, to Croatia in 1802 and to Bereg County in 1803; it makes the specimen firmly linked to the protologue of C. elongatus. The sheet bears three fragments: a branch on the right side, densely leafy and abundantly flowering, corresponding to C. cinereus; a small fragment in immature fruit in the middle, also belonging to C. cinereus (possibly collected in 1803 from the locality in Bereg County mentioned in
This lectotype agrees with the usage in the Hungarian exsiccata (
The treatment of C. leucotrichus has been controversial.
Although
All the original material of C. czerniaevii belongs to C. elongatus.
Chamaecytisus korabensis was recently described by
The earlier records of C. lindemannii from Belarus (
Although the species is not included in national or regional Red Lists, it occurs in some protected areas, for example, in the Mikhailovskaya Tselina Nature Reserve in Ukraine and in the Utrish Nature Reserve in Russia.
–Cytisus communis Lindem. in Bull. Soc. Imp. Naturalistes Moscou 40(1): 494 (1867), nom. illeg. superfl. – Cytisus hirsutus subsp. ratisbonensis (Schaeff.) Briq., Étud. Cytises Alpes Mar.: 167 (1894) – Chamaecytisus ratisbonensis (Schaeff.) Rothm. in Feddes Repert. 53(2): 143 (1944).
[icon] Schaeffer, Bot. Exped.: tab. in prim. lib. 1760 (presumably holotype).
Prostrate shrubs up to 20 cm above ground with long branches. Leaves with obovate to elliptic leaflets, glabrous above, with appressed hairs 0.4–0.8 mm long below, petioles densely covered with appressed hairs. Flowers strictly lateral, 1–4 in axils, on pedicels 3–5(7) mm long, pale yellow; calyx 11–14 mm long, with laxly appressed hairs 0.8–1.2(1.6) mm long; standard suborbicular, glabrous above.
Europe: Austria (
The species occurs in dry meadows among pine and oak mountain forests.
2n = 48 (
The herbarium collections of Jacob Christian Schaeffer may be kept at REG. So far, the only, but unambiguous original element available to us is the illustration in the protologue.
Before
–Chamecytisus ratisbonensis auct.: Tzvelev 1989;
Poland. “Regio Cracoviensis: inter pagum Zabierzów et vicum Szczyglice, ad declive abruptum loessicum, 17.05.1973, A. Pałkowa & T. Tacik [Flora Poloniae Exsiccata No. 636] (holotype H1293884; isolectotypes KRAM249040 and distributed to other herbaria). Fig.
The new species is named after Poland, the country of its main distribution and type locality.
Prostrate shrubs up to 20 cm above ground with long branches. Leaves with obovate to elliptic leaflets, glabrous above, with appressed hairs 0.4–0.8 mm long below, petioles densely covered with appressed hairs. Flowers strictly lateral, 1–4 in axils, on pedicels 3–5(7) mm long, pale yellow; calyx (7)8–10 mm long, with (laxly) appressed hairs 0.6–0.8(1) mm long; standard suborbicular, glabrous above.
Europe: Poland, Ukraine. Its occurrence in western Belarus is expected due to the presence in Poland, 15 km from the border.
The species occurs in dry meadows or on calcareous denudations, on open slopes of hills and mountain foothills.
2n = 24 (
This species is most similar to C. ratisbonensis, from which it differs by its smaller flowers and shorter pubescence. It replaces the latter species in southern and eastern Poland and Ukraine.
–Cytisus ratisbonensis subsp. cinereus (Host) Jáv., Magyar Fl. 2: 609 (1924).
=Cytisus horniflorus Borbás, Balaton Fl.: 299 (1900), syn. nov. Type. Hungary. “In arenosis silvaticis ad Monor in Hung. centrali”, 08.06.1887, V. Borbás (lectotype BP581457, designated by
=Cytisus paczoskii V.I.Krecz. in Bot. Zhurn. SSSR 25: 261 (1940), syn. nov. – Chamaecytisus paczoskii (V.I.Krecz.) Klásk. in Preslia 30(2): 214 (1958). Type. Ukraine. Ternopol Region: “Silva prope pag. Kidancy (non procul stat. viae ferrariae Maximovka)”, 26.04.1916, A.I. Michelson (holotype LE01024080).
Cultivation, originated from Hungary. “Ex Hort.” [Botanical Garden at Belvedere in Vienna, now Botanical Garden of the University of Vienna], Hb. Host 4148 (lectotype W1885-4148, designated here: https://w.jacq.org/W18850004148). Fig.
Upright shrubs with erect, basally ascending stems up to 60(80) cm tall and long branches. Leaves with elliptic to obovate leaflets, glabrous above (the basal leaves are slightly hairy above), with appressed hairs 0.4–0.8(1.2) mm long below, petioles sparsely covered with laxly appressed hairs. Flowers strictly lateral, 1–4 in axils, on pedicels 3–5 mm long, yellow; calyx 11–14 mm long, with laxly appressed to subpatent hairs 0.6–1.2(1.5) mm long; standard subrbicular, glabrous or hairy above.
Europe: Austria, Slovakia, Serbia, Hungary, Romania, Poland, Ukraine (
The species occurs in open places, meadows and forest margins on plains and slopes of hilly uplands, often on sandy or calcareous substrates.
2n = 48 (
Cytisus cinereus was described from sandy and forested areas of Hungary (
Cytisus cinereus and C. horniflorus were distributed in the same exsiccatae as different taxa (
In Poland,
–Chamecytisus ratisbonensis auct.:
Upright shrubs with basally prostrate stems up to 40(60) cm tall and short branches. Leaves with obovate leaflets, glabrous above, with appressed hairs 0.4–0.6(0.8) mm long below, petioles sparsely to densely covered with laxly appressed hairs. Flowers strictly lateral, 1–4 in axils, on pedicels 5–10 mm long, pale yellow; calyx 12–14 mm long, with laxly appressed hairs 0.6–0.8 mm long; standard broadly elongate, glabrous above.
Europe: Poland, Belarus, Ukraine. This is the first attempt to circumscribe the distribution area of this species.
The species occurs in margins of dry pine and mixed forests.
2n = 100 (
The first name intended for this species, Cytisus pubescens Gilib., was originally introduced in
Comparisons of selected diagnostic characters from the protologue of Cytisus lithuanicus (
Characters / species | C. lithuanicus, protologue | C. cinereus | C. lithuanicus, our work | C. polonicus | C. ruthenicus |
---|---|---|---|---|---|
Habit | “frutex basi decumbens sed rami erecti” | erect, basally ascending, not prostrate | basally prostrate, with erect branches | prostrate | erect |
Plant height | “pedalis & cubitalis” = 30–45 cm | up to 40–60(80) cm | up to 40(60) cm | up to 20 cm | up to 120(200) cm |
Calyx length | “sex linearum” = 13.5 mm | 11–14 mm | 12–14 mm | (7)8–10 mm | 10–12 mm |
Peduncle length | “vix quator linearum” = less than 9 mm | 3–5 mm | 5–10 mm | 3–5(7) mm | 5–7 mm |
The habit of C. lithuanicus described in the protologue agrees with the octoploid species, whereas the match with C. ruthenicus (tall erect shrub) is impossible and the correspondence with C. polonicus (prostrate shrub) is less likely. The most important character is the calyx length, which immediately rejects C. polonicus (shortest calyces), but perfectly matches the octoploid (longest calyces). The peduncle length also disagrees with C. polonicus, which typically has shorter pedicels (subsessile flowers), whereas the octoploid plants usually have longer pedicels (lax flowers). Cytisus cinereus is similar to the plant described by Gilibert in the calyx length, but its stems are usually taller and pedicels are shorter; besides, the pubescence on the calyces of C. cinereus is long and laxly appressed to subpatent, and is usually perceived as golden-coloured because of its length and density (
All these characters strongly indicate that the only species corresponding to the protologue of C. lithuanicus can be the octoploid, for which we resurrect this species name here.
Cytisus lithuanicus was described from the western vicinity of Białystok (present-day Poland), which was part of the Grand Duchy of Lithuania at the time of description. The original material was missing in the personal herbarium of Gilibert (KW) already by the beginning of the 20th century (
This species was formerly included in C. ratisbonensis (
–Chamaecytisus wulffii (V.I.Krecz.) Klásk. in Preslia 30(2): 214 (1958).
Small prostrate shrubs with abundantly branching stems up to 20 cm above ground. Leaves with obovate to oblong leaflets, hairy above, with numerous appressed hairs 0.3–0.7 mm long below, petioles sparsely covered with appressed to spreading hairs. Flowers strictly lateral, 1–4 in axils, on pedicels 3–5 mm long, yellow; calyx 14–15 mm long, with laxly appressed hairs 0.5–1 mm long; standard subrotund, partly hairy above.
Europe: Crimea (
The species occurs on open gravelly and rocky slopes and in alpine meadows at the upper limit of pine forests.
Unknown.
This species is most similar to Cytisus polytrichus M.Bieb., which occurs in the same area in the Crimea, but in the upper mountain zone and differs by patent (vs. appressed) hairs on its calyces and pedicels. Populations of both taxa may locally overlap (
1 | Leaves glabrous above | 2 |
– | Leaves variously hairy above | 6 |
2 | Pubescence completely appressed, sometimes plants are subglabrous to totally glabrous; calyces with appressed hairs 0.4–0.6 mm long; stems erect, up to 1(1.2) m tall | Cytisus ruthenicus |
– | Pubescence with subappressed to subpatent hairs over 0.6 mm long; stems prostrate or erect and basally ascending, not so tall | 3 |
3 | Flowers smaller; calyces (7)8–10 mm long, hairs 0.6–0.8(1) mm long | Cytisus polonicus |
– | Flowers larger; calyces 11–14 mm long, hairs 0.6–1(1.6) mm long | 4 |
4 | Calyces with laxly appressed hairs 0.6–0.8 mm long | Cytisus lithuanicus |
– | Calyces with laxly appressed or subpatent hairs 0.6–1.2(1.6) mm long | 5 |
5 | Calyces with laxly appressed hairs 0.8–1.2(1.6) mm long; stems procumbent, up to 20 cm above ground | Cytisus ratisbonensis (outside Eastern Europe) |
– | Calyces with laxly appressed to subpatent hairs 0.6–1.2(1.5) mm long; stems erect, basally ascending, up to 60 cm tall | Cytisus cinereus |
6 | Calyx 14–15 mm long; stems procumbent, up to 20 cm above ground | Cytisus wulffii |
– | Calyx 10–12 mm long; stems erect or basally ascending, 30–150 cm tall | 7 |
7 | Calyces with appressed or laxly appressed hairs up to 0.6(0.8) mm long | 8 |
– | Calyces with mostly subpatent hairs up to 1.2 mm long | 9 |
8 | Leaflets lanceolate or narrowly lanceolate, densely and evenly hairy above | Cytisus borysthenicus |
– | Leaflets lanceolate to elliptic, sparsely hairy to subglabrous above | Cytisus kreczetoviczii |
9 | Leaves densely and evenly hairy above; calyx with subpatent hairs 0.8–1.2 mm long | Cytisus elongatus |
– | Leaves sparsely hairy to subglabrous or nearly glabrous above; calyx with appressed and subpatent hairs 0.4–0.9 mm long | Cytisus semerenkoanus |
Our treatment is a further development of
This revision provides a taxonomic backbone for further studies in Cytisus sect. Tubocytisus. Much further work is still required to establish chromosome counts for all its taxa and to uncover their evolutionary history. Distribution areas in the Balkans and some areas of Central Europe (Slovakia, Hungary) are unclear because of the lumping approach in local treatments and require complete revision. Recent hybridisation processes remain understudied.
The taxa of C. ratisbonensis group can be distinguished by differences in leaf shape and pubescence and in calyx size and pubescence; life form and habit provide important complementary information. These taxa also differ in their distribution areas and in their preference for elevation, substrate and vegetation type.
We would like to express our deep gratitude to Arto Kurtto (Helsinki) for continuous support and encouragement. VNT is grateful to curators of the Herbaria which he visited during this work. Bruno Wallnöfer (Vienna) kindly confirmed the microcharacters of the type specimen of Cytisus cinereus, Otakar Šída (Prague) and Robert Vogt (Berlin) kindly observed pubescence details on the specimens of C. elongatus at PR and B. Larisa Semerenko (Minsk) discussed her caryological work. Patrik Mráz (Prague) sent copies of rare literature. Denis Melnikov (Saint-Petersburg) provided scanned images of type specimens from LE. Serena Marner (Oxford) kindly communicated images of Gruner’s specimens kept at OXF.
The authors have declared that no competing interests exist.
No ethical statement was reported.
Open access was funded by the University of Helsinki.
ANS and VNT developed the taxonomic concept and revised the nomenclature. VNT collected and treated the material with the participation of ANS. ANS wrote the manuscript with the input from VNT. Both authors agreed to the final version of the manuscript.
Alexander N. Sennikov https://orcid.org/0000-0001-6664-7657
Valery N. Tikhomirov https://orcid.org/0000-0003-1822-0557
The dataset of distributional records collected for the present work was published through the Internet Archive (available online: https://archive.org/details/cytisus-ratisbonensis-dataset).