Biologia 66/4: 595—603, 2011 Section Botany DOI: 10.2478/s11756-011-0058-6 Notes on the genus Taraxacum in Slovakia. I. Taraxacum sect. Hamata: a new group of dandelions in Slovakia Bohumil Trávníček & Radim J. Vašut* Department of Botany, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-78371 Olomouc, Czech Republic; e-mail: bohumil.travnicek@upol.cz, radim.vasut@upol.cz Abstract: The hamate dandelion section (Taraxacum sect. Hamata H. Øllg.) represents a morphologically tight group of taxa, distributed in the oceanic and sub-oceanic regions of Europe. In Central Europe, it is mostly confined to freshly moist meadows, as well as places in the shade within urban areas. The known distribution area in Europe until now extended towards the E part of the Czech Republic and S Poland. During the past six years, we have discovered an additional eleven localities of hamate dandelions in NW and N Slovakia, which represents a corrected south-eastern limit for the distribution area of this section. In this paper, we discuss seven recognized taxa (T. boekmanii, T. fusciflorum, T. hamatiforme, Taraxacum hamatum, T. lamprophyllum, T. pseudohamatum, and T. quadrans). We provide a determinative key to the Slovakian hamate dandelions, brief species descriptions, comments on their distribution, a distribution map of the section in Slovakia, as well as images of all of the newly found species. Key words: Taraxacum; apomixes; dandelion; section Hamata; species distribution; taxonomy; Slovakia Introduction The genus Taraxacum belongs to one of the most intriguing taxonomical groups of the European Flora. Due to the presence of various reproduction modes, the genus is rich in the number of species. Dandelions are divided into ca. 55 sections (Kirschner & Štěpánek 1997a, 2004). Ancestral sections have only a few species, and these are usually diploid sexuals (e.g. sections Piesis, Dioszegia, Glacialia, etc.). Advanced sections consist of tens or even hundreds of species: mostly with an abundance of apomictic microspecies; usually as only one or two diploid sexuals, as well. These sexuals are characterized by large morphological variations. Conversely, apomicts have very narrow variability; however they can have large morphological plasticity. Sometimes, apomicts possess the morphological characters of two different sections. The Taraxacum species diversity has relatively lacunose information. The most explored European region is in Scandinavia, especially Sweden, Denmark and Finland, where research had already started by the first half of the 20th century. It was followed from the 30’s (and even more so since the 50’s) in other the European countries, especially in the Netherlands, United Kingdom, and Germany. However, the central-European Taraxacum Flora remained almost unexplored until the 80’s. One of the reasons for this was the fact, that the Central European Taraxacum Flora is much more de* Corresponding author c 2011 Institute of Botany, Slovak Academy of Sciences
ceptive then the Scandinavian one. This is due to two of the major groups having diploid sexuals in the southern parts of Central Europe. The knowledge of Taraxacum Flora in Slovakia has been rather limited to date. Several specialists have contributed to the knowledge of Slovakian dandelions, but unfortunately these publications were based just on accidental findings (Klášterský 1938; Richards 1970; Doll 1976). The first checklists or studies of Slovak dandelions, based on large population samples, were by Kirschner & Štěpánek (1992b, 1995, 1998a,b). They published a summary of species found during their field research encompassing a long time period. They recognized nine sections of dandelions in Slovakia, i.e. sect. Dioszegia (with only one species: T. serotinum), sect. Piesis (with only one species: T. bessarabicum), sect. Erythrocarpa (with only one species: T. erythrocarpum), sect. Alpina, sect. Alpestria, and sect. Fontana (these 3 sections with unclear relationships, and rather unexplored species diversity), sect. Palustria (42 species, Kirschner & Štěpánek 1998a,b), sect. Erythrosperma (5 species), and sect. Ruderalia (ca. 35 species). Important contributions to the recent information of the Taraxacum Flora in Slovakia were also made by several minor studies, narrowly focused to various taxa, e.g. Kirschner & Štěpánek (1985a,b, 1986, 1992a, 1997b, 2000), Procházka et al. (1999a,b,c), Øllgaard (2003), Schmid et al. (2004), Vašut & Trávníček 596 B. Trávníček & R.J. Vašut (2004), Vašut et al. (2005), and Trávníček & Štěpánek (2008). In our series of papers, would like to bring new findings of Slovak dandelion flora, in light of modern views of the taxonomy of the Taraxacum genus. We will present our results from the field studies on sections Erythrosperma (lesser dandelions), Ruderalia (common dandelions), plus a newly discovered sect. Hamata (hamate dandelions). Taraxacum sect. Hamata H. Øllgaard: a new group of dandelions in Slovakia Taraxacum sect. Hamata is an evolutionary advanced section (Wittzell 1999; Kirschner et al. 2003), and it is comprised exclusively of triploid apomicts. Morphologically, it is very close to section Ruderalia, from which it was separated (Øllgaard 1983). The Hamate dandelions are presently considered as a separate section, especially due to specific ecological preferences and a tight morphological homogeneity within the group. The section represents a group of dandelions with a strong preference to either an oceanic or sub-oceanic climate. Taxa of this section were reported from NW, N and C Europe; i.e. Iceland, Faroe Islands, United Kingdom, Ireland, France, Belgium, the Netherlands, Denmark, Sweden, Finland, Norway, Estonia, Germany, Poland and the Czech Republic (Tacik 1980; Øllgaard 1983; Øllgaard in litt., Dudman & Richards 1997; Hagendijk et al. 1982; Kirschner & Štěpánek 1995; Sackwitz et al. 1998; Uhlemann 2003; Dudman et al. 2006). In Central Europe, species of this section grow exclusively in regions with a sub-oceanic climate, and ecologically prefer freshly wet meadows, preferably with lower pH, a medium content of minerals, and partly disturbed vegetation (Trávníček et al. 2010). Hamate dandelions often also grow in places in the shadows in meadows and lawns within urban areas. Morphologically, they can be separated from the sect. Ruderalia by the combination of the following characteristics: 1) blackish to bluish green, often pruinose involucres; 2) arcuate (not sigmoid) outer bracts, 3) the leaves usually having distinctly hamate lateral lobes, and usually not having a complicated leaf shape; 4) the midrib of the leaves with gentle red stripes (i.e. not fully green, pink, or red). Furthermore, Mogie & Richards (1983) reported the lack of one of the NOR chromosomes in 11 Hamata species, and Øllgaard (1983) considers this fact as yet another characteristics of the section Hamata. However, in T. lamprophyllum all three NOR chromosomes were observed in mitotic cells, sometimes with rather distant satellite (Vašut et al. in prep.). Currently, section Hamata comprises of roughly 30 species (Kirschner et al. 2007–2009). All taxa are very similar morphologically, and their determination requires experience with dandelion recognition. It is often necessary to study the morphological plasticity on a whole population. The vast majority of hamate taxa grow in NW Europe; and only 10–12 species occur in Central Europe (Tacik 1980; Kirschner et al. 2002; Uh- Fig. 1. Distribution of Taraxacum sect. Hamata in Slovakia based on field observations. lemann 2003). Despite an intensive Taraxacum research in Central Europe, the section so far had not been recorded from Slovakia. In our research we intended to look for species of section Hamata at potential sites in Slovakia. We discovered seven described species during our six years of observation, which we characterize in this paper. We recorded hamate dandelions at 11 localities; these were only in sub-oceanic regions of NW and N Slovakia. The overall distribution of section Hamata in Slovakia is shown in Fig. 1. Taraxacum sect. Hamata H. Øllgaard Pl. Syst. Evol. 141: 201, 1983. Species of the sect. Hamata are usually mid-sized dandelions, sometimes as robust as some species of section Ruderalia. Combination of main diagnostic characters: leaves araneously pilose or glabrous; leaf blades usually with hamate lateral lobes; midrib conspicuously coloured with gentle reddish-violet stripes; petioles never or indistinctively alate, pale to conspicuously coloured. Capitula usually 3.5–5.5 cm wide in diameter, florets mid- to deep yellow; involucra dark green and often pruinose, outer involucral bracts lanceolate, slightly inordinately composed, spreading to recurved; without any corniculation at apex, usually conspicuously whitish pruinose at the upper surface, blackish green beneath, and pruinose as well – often with a narrow white margin; inner bracts usually blackish at apex when closed in the bud. Ligules of marginal florets flat, usually striped in greyish brown-red, terminal teeth dark-violet at apex; pollen present, pollen grains with varying size in diameter (reflecting unequal meiosis of triploids). Achenes straw-coloured, 3.5–4.5 mm long with a 0.3–0.7 mm long cylindrical pyramid, achene body slightly spinulose in upper part; rostrum >10 mm long, pappus whitish. All known species are triploid, 2n = 24. Flowering is usually on May (April to June). Determination key to the species of Taraxacum sect. Hamata in Slovakia. 1a Outer involucral bracts without distinct hyaline margin; outer ligules with rather broad dark-coloured Taraxacum sect. Hamata in Slovakia b 2a b 3a b 4a b 5a b 6a strip (almost as wide as the ligule); at least some of the achene spines recurved. – Outer involucral bracts 3.0–4.5 mm wide, recurved, margins slightly revolute . . . . . . . . . . . . . . . . . . . . . . T. fusciflorum H. Øllgaard Outer involucral bracts with narrow, but conspicuous, white hyaline margin; the dark-coloured strip on outer ligules as wide (at maximum) as 2/3 the width of the ligules; achene spines ± straight . . . . . . . . . . . 2 Outer involucral bracts usually 3.5–4.5 mm wide; plant often quite robust, fully blooming capitulas up to 5.5 cm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Outer involucral bracts usually 2.5–3.5 mm wide; plants usually midsized or quite small (often gracile); fully blooming capitulas 3.5–4.5 cm in diameter . . 5 Midrib of leaf blade on both sides conspicuously coloured in reddish-violet to the apex; lateral lobes of outer and middle leaves of the leaf-rosette deflexed, distinctively broad (± as broad as long); terminal lobe usually distinctively longer then broader, obtuse to rounded; leaves (especially inner ones) conspicuously hairy on upper surface . T. boekmanii (see 7b) Midrib of leaf blade less intensively coloured, usually only in lower half of the leaves, and only inconspicuously coloured beneath; lateral lobes directing obliquely downwards or ± patent, quite narrow, usually as long as broad or frequently longer then broad; terminal lobe usually as long as broad, sometimes with prolongated lingulate apex; leaves almost glabrous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Lateral lobes of the middle and inner leaves (strongly) dentate on distal margin (sometimes with one large tooth), patent to slightly recurved; petioles intensely reddish-violet coloured. – Terminal lobe often with the prolongated lingulate apex, usually relatively small; outer involucral bracts with very conspicuous whitish hyaline margin; interlobes of middle and inner leaves usually with at least one tooth; lateral lobes usually blunt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. lamprophyllum M. P. Christiansen Lateral lobes of the leaves entire or sparsely denticulate on distal margin, usually distinctly recurved; petioles faintly reddish-violet coloured. – Terminal lobe usually obtuse or subacute, occasionally with very short lingulate apex; outer involucral bracts with conspicuous whitish hyaline margin; interlobes usually entire or filiform-denticulate; lateral lobes acute; leaves dark . . . T. pseudohamatum Dahlst. Lateral lobes ± triangular, relatively narrow, at least as long or longer than wide, acute, gradually narrowed at apex, distal margin ± straight to slightly convex or slightly sigmoid; terminal lobe usually triangular or triangular-helmet-shaped . . . . . . . . . . . . . . 6 Lateral lobes (especially of the outer and middle leaves) conspicuously hamate, broad (as long as wide), with short obtuse apex, distal margin convex; terminal lobe usually helmet- or ovate-shaped in outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Lateral lobes in asymmetric position on leaf blade (sometimes almost alternating), ± straight, narrow, distal margin ± straight and entire, sometimes in 597 upper part with tooth; interlobes usually blotched and with one large tooth. – Outer involucral bracts sometimes with inconspicuous hyaline margin, basal bracts often fine and narrow to squamus-shaped; lateral lobes and their apices directing obliquely downwards; petioles and basal part of midribs vividly coloured reddish-violet . . T. hamatiforme Dahlst. b Lateral lobes in ± symmetric position on leaf blade (opposite), distal margin straight to slightly sigmoid, often denticulate (especially in middle and inner leaves); interlobes short, entire or slightly denticulate, usually not blotched. – Whitish hyaline margin of outer involucral bracts narrow, but conspicuous, basal bracts not remarkably small; lateral lobes directing obliquely downwards, with patent apices; petioles and midribs ± intensively reddishviolet coloured (even in upper part of midrib); leaves greyish to bluish-green . . T. quadrans H. Øllgaard 7a Midrib of leaf blades faintly ± reddish-violet coloured in the basal part; terminal lobe ± as long as wide, ovate-shaped in outline (occasionally with hinted lingulate apex); leaves almost glabrous. – Lateral lobes of leaves distinctly hamate, distal margin remarkably convex, entire, apex blunt; interlobes entire or gently denticulate; outer involucral bracts recurved to ± spreading, with narrow hyaline margin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T. hamatum Raunk. b Midrib in all parts of leaf blade intensively coloured reddish-violet (on both surfaces); terminal lobe usually longer than broader, helmet-shaped, obtuse to rounded; leaves (especially the inner ones) conspicuously hairy. – Lateral lobes recurved, broad, usually obtuse, interlobes entire or slightly denticulate; outer involucral bracts recurved, with narrow hyaline margin . . . . . . . . . . . . . . . . . . . . . . . . T. boekmanii Borgvall List of species of Taraxacum sect. Hamata in Slovakia 1. Taraxacum hamatum Raunk. Dansk Ekskursionsfl., ed. 2, 255, 1906. (Fig. 2) A medium sized, sometimes small plant, 10–20 (–25) cm tall. Leaves dark olive green, with or without dark blotch; midrib coloured pink to purple in exposed sites, greenish in shadier locations; lateral lobes 3–5 on both sides, regular, recurved, hamate, rather short, subacute to sometimes obtuse, with distal margin convex, usually ± entire, the proximal margin straight to concave; terminal lobe usually entire, rather small, sagittate to ovate in outline; petiole narrow, ± unwinged, pink to purple. Capitulum 4.0–4.5 cm in diameter; exterior bracts recurved to spreading or sometimes ± erect, 10–12 mm long, 2.5–3.5 mm wide, forming a stellate involucre in bud, with very narrow hyaline margin, whitish pruinose on upper surface, blackish green and pruinose on lower surface; styles discoloured. Achenes 3.5–4.0 mm long, cone 0.5–0.6 mm long. The species was found in several countries of W, NW, N and Central Europe, specifically: Iceland, Faroe Islands, Great Britain, Ireland, the Netherlands, Bel- 598 B. Trávníček & R.J. Vašut Fig. 2. Herbarium specimen of Taraxacum hamatum. (NW Slovakia, Hrubý Buk near Turzovka) Bar = 5 cm. Fig. 3. Herbarium specimen of Taraxacum hamatiforme. (NW Slovakia, Vyšný Koniec near Čadca) Bar = 5 cm. gium, France, Germany, Denmark, Norway, Sweden, Finland, Czech Republic, Poland, and Estonia. (Tacik 1980; Hagendijk et al. 1982; Øllgaard 1983, 1994; Øllgaard in litt., Kirschner & Štěpánek 1995; Dudman & Richards 1997; Sackwitz et al. 1998; Kirschner et al. 2002; Uhlemann 2003). The new record from Slovakia represents just one find at the semi-natural locality in the Kysuce region (SW Slovakia). Therefore, it might be considered as a threatened species. According to the Red List of Vascular Plants in Slovakia (Feráková et al. 2001) it should be considered as category “EN”. Distribution in Slovakia: 28. Západné Beskydy: Hrubý Buk settlement, N of the town of Turzovka, wet meadow along the brook, S of the road towards the Hlavice settlement, 0.6 km W from the church in the settlement, 49◦ 28′ 09′′ N, 18◦ 37′ 06′′ E, leg. B. Trávníček & R.J. Vašut, 14. V. 2004, OL. Republic, and Poland (Tacik 1980; Hagendijk et al. 1982; Øllgaard 1983; Øllgaard in litt., Kirschner & Štěpánek 1995; Dudman & Richards 1997; Sackwitz et al. 1998; Kirschner et al. 2002; Uhlemann 2003). We found this species in Slovakia at three sites in the Kysuce region. It is very likely that species will be found in more localities in the region. Species was growing on semi-natural or slightly ruderalized wet meadows. Due to limited distribution of the species, it can be considered as category “EN” in Slovakia (according to Feráková et al. 2001). Distribution in Slovakia: 28. Západné Beskydy: Křižkovci settlement NW of the Čadca town, small meadows and roadsides in the N part of the settlement, 49◦ 29′ 12′′ N, 18◦ 41′ 12′′ E, leg. B. Trávníček & R.J. Vašut, 14. V. 2004, OL. – Čadečka village near town of Čadca, lawns and roadsides near Šimčiskovci settlement, 49◦ 28′ 06′′ N, 18◦ 52′ 15′′ E, leg. B. Trávníček, 18. V. 2005, OL. – Vyšný Koniec village near Čadca town (near village of Čierne), small meadow at the road towards Chovancovci settlement near crossroad Vyšný Koniec – Chovancovci – Mojovci, 49◦ 29′ 55′′ N, 18◦ 51′ 10′′ E, leg. B. Trávníček, 18. V. 2005, OL. 2. Taraxacum hamatiforme Dahlst. in Lindman Svensk Fanerogamfl. 568, 583, 1918. (Fig. 3) A medium-sized plant, 10–20 (–25) cm tall. Leaves medium to dark green, irregularly and asymmetrically lobate; interlobes often blotched, basal part of midrib ± purple; lateral lobes 3–5 on both sides, patent or recurved, usually narrowly triangular, acute, with distal margin ± straight or sometimes slightly concave; interlobes often with tooth or teeth; terminal lobe triangular to sagittate, sometimes with elongated apex; petiole narrow, ± unwinged, deep purple. Capitulum 4.0–4.5 cm in diameter; exterior bracts spreading to recurved, 10–11 mm long, 2–3 mm wide, greyish to whitish green on upper surface, dark shiny brown-green on lower surface, with an indistinct border, lower ones often rudimentary; styles discoloured. Achenes 3.5–4.0 mm long, cone 0.5–0.6 mm long. Taraxacum hamatiforme is widely distributed species. It is regionally the most frequent species of the section. T. hamatiforme was recorded from most of the W and N European countries, i.e. Faroe Islands, Great Britain, Ireland, the Netherlands, Belgium, France, Germany, Denmark, Norway, Sweden, Finland, Czech 3. Taraxacum pseudohamatum Dahlstedt in Druce Rep. Bot. Soc. Exch. Club Brit. Isles 1931, 9/5: 564, 1932. (Fig. 4) A medium sized to large and robust plant, 15–35 cm tall. Leaves dark, dull olive green, interlobes with or without dark blotch, midrib ± purple or green in upper part; lateral lobes (3–) 4–5 (–6) on both sides, patent to recurved, ± short, hamate, (sub)acute, with distal margin usually convex, as a rule without teeth (or sometimes filiform dentate), the proximal margin ± straight or concave; interlobes entire to filiform dentate; terminal lobe usually helmet-shaped, blunt to subacute, petiole narrowly winged in upper part, ± sordid purple. Capitulum 4.5–5.5 cm in diameter; exterior bracts spreading to recurved, 11– 14 mm long, 3.5–4.5 mm wide, distinctly bordered, pale green and greyish pruinose on upper surface, dark green and pruinose on lower surface; styles dis- Taraxacum sect. Hamata in Slovakia 599 Fig. 4. Herbarium specimen of Taraxacum pseudohamatum. (N Slovakia, Gerlachov) Bar = 5 cm. coloured. Achenes ca. 3.5 mm long, cone 0.5–0.7 mm long. The species was recorded from following countries: Great Britain, Ireland, the Netherlands, France, Denmark, Sweden, Finland and the Czech Republic (Øllgaard 1983; Øllgaard in litt., Kirschner & Štěpánek 1995; Dudman & Richards 1997; Sackwitz et al. 1998; Kirschner et al. 2002; Uhlemann 2003). In Slovakia, only one locality is known in the northern part of the country. It grows in semiruderal wet grassy places within the urban area of the village. Due to its very rare occurrence in Slovakia, it can be considered as category “EN” (according to Feráková et al. 2001). Distribution in Slovakia: 26b. Spišské kotliny: Gerlachov village near town of Poprad, lawns and roadsides in NW part of the village, 49◦ 05′ 52′′ N, 20◦ 12′ 26′′ E, leg. B. Trávníček & R.J. Vašut, 26. V. 2006, OL. 4. Taraxacum lamprophyllum M. P. Christiansen Dansk Bot. Arkiv 9(2): 12, 1936. (Fig. 5) A medium to large sized and robust plant, (15–) 20–35 cm tall. Leaves mid- to dark green, interlobes without or with dark blotch, midrib ± purple or green in upper part; lateral lobes 4–6 on both sides, patent or recurved, with apex acute to subacute or obtuse (when the lobe is entire), the distal margin ± straight or convex, often dentate, frequently with at least 1 large tooth, the proximal margin ± straight or concave, sometimes dentate; interlobes usually dentate; terminal lobe triangular in outline to triangular-sagittate, often with elongated apex, sometimes dentate; petioles unwinged, at least below, purple. Capitulum 4.5–5.5 cm in diameter; exterior bracts spreading to recurved, 11–14 mm long, 3.0–4.5 mm wide, greyish to whitish pruinose on upper surface, dark olive green on lower surface, narrowly distinctly white bordered; styles discoloured. Achenes 3.5–4.0 mm long, cone 0.5–0.6 mm long. The species is known from great part of W, NW and N Europe. It is also quite common in Central Europe. Records come from the following countries: Great Fig. 5. Herbarium specimen of Taraxacum lamprophyllum. (NW Slovakia, Křižkovci near Čadca) Bar = 5 cm. Britain, Ireland, the Netherlands, Belgium, France, Germany, Denmark, Sweden, Finland, Czech Republic and Poland (Tacik 1980; Hagendijk et al. 1982; Øllgaard 1983; Øllgaard in litt., Kirschner & Štěpánek 1995; Dudman & Richards 1997; Sackwitz et al. 1998; Kirschner et al. 2002; Uhlemann 2003). We found this species in semi-natural or semiruderal wet meadows at 2 (–3) localities in NW Slovakia. It grows on wet meadows, but also in shaded grasses along the roads. Apparently, species might be more frequent at ecologically appropriate localities in the region. However, species is quite rare in Slovakia, and can be considered as category “EN” (according to Feráková et al. 2001). Distribution in Slovakia: 28. Západné Beskydy: Křižkovci settlement NW of the Čadca town, small meadows and roadsides in the N part of the settlement, 49◦ 29′ 12′′ N, 18◦ 41′ 12′′ E, leg. B. Trávníček & R. J. Vašut, 14. V. 2004, OL. – Suchá Hora village near Trstená town, wet meadows 1.5 km NNE (-N) of the village, 49◦ 22′ 54′′ N, 19◦ 47′ 26′′ E, leg. B. Trávníček & R.J. Vašut, 14. V. 2007, OL (T. cf. lamprophyllum). – Oravice settlement near Trstená town, lawns and wet meadows in the settlement and along the road towards Habovka village, 49◦ 17′ 39′′ N, 19◦ 44′ 11′′ E, B. Trávníček, 14. V. 2007, OL. 5. Taraxacum boekmanii Borgvall Acta Horti Gotoburg. 23: 4, 1959. (Fig. 6) A medium sized plant, 15–25 (–30) cm tall. Leaves dark green, somewhat hairy, midrib bright purple to 600 B. Trávníček & R.J. Vašut Fig. 6. Herbarium specimen of Taraxacum boekmannii. (N Slovakia, Čirč near Stara Ľubovňa) Bar = 5 cm. Fig. 7. Herbarium specimen of Taraxacum quadrans. (N Slovakia, Oravice near Trstená) Bar = 5 cm. apex, often with red veining to leaf; lateral lobes 3–5 on both sides, recurved, ± hamate, rather short, usually subacute to obtuse, with distal margin ± straight or convex, entire or filiform dentate, the proximal margin usually ± straight; terminal lobe equalling (or often larger than) pairs of lateral lobes, entire, with obtuse to rounded apex; petiole narrowly winged, shiny purple. Capitulum ca. 4 cm in diameter; exterior bracts spreading to recurved, 10–12 mm long, 2.5–3.5 mm wide, with very narrow hyaline margin, pale green, whitish pruinose on upper surface, blackish green and ± pruinose on lower surface; styles discoloured. Achenes 3.8–4.5 mm long, cone ca. 0.5 mm long. The species T. boekmanii is growing in W, NW and N Europe, rarely also in Central Europe. It was recorded in following countries and regions: Faroe Islands, Great Britain, Ireland, the Netherlands, France, Germany, Denmark, Sweden, Czech Republic and Poland (Tacik 1980; Hagendijk et al. 1982; Øllgaard 1983; Øllgaard in litt., Kirschner & Štěpánek 1995; Dudman & Richards 1997; Sackwitz et al. 1998; Kirschner et al. 2002; Uhlemann 2003). In Slovakia, it is known from only a single locality in northern Slovakia. It was growing in semiruderal wet grass. Although it might be found in other ecologically adequate localities in Slovakia, it can be considered as category “EN” (according to Feráková et al. 2001). Distribution in Slovakia: 30b. Čergov: Čirč village near Stará Ľubovňa town, lawns in centre of the village, 49◦ 16′ 43′′ N, 20◦ 55′ 27′′ E, leg. B. Trávníček, 30. IV. 2007, OL. to narrowly winged, purple. Capitulum 3–4 cm in diameter; exterior bracts spreading, 10–12 mm long, 3.0–3.5 (–4.0) mm wide, distinctly narrow-bordered, pale green on upper surface, blackish green and ± pruinose on lower surface; styles discoloured. Achenes 3.7–4.0 mm long, cone ca. 0.6 mm long. The species has similar distribution as the previous taxa, i.e. it is known from N, NW and Central Europe, i.e. from the following countries: Great Britain, Ireland, the Netherlands, France, Germany, Denmark, Sweden, Czech Republic and Poland (Tacik 1980; Hagendijk et al. 1982; Øllgaard 1983; Kirschner & Štěpánek 1995; Dudman & Richards 1997; Sackwitz et al. 1998; Kirschner et al. 2002; Uhlemann 2003). It grows at a single locality in NW Slovakia, in wet pasture. Species was quite abundant at this unique locality. However, it is better considered as category “EN” in Slovakia (according to Feráková et al. 2001). Distribution in Slovakia: 28. Západné Beskydy: Oravice settlement near town of Trstená, lawns and wet meadows in the settlement and along the road towards Habovka village, 49◦ 17′ 39′′ N, 19◦ 44′ 11′′ E, leg. B. Trávníček & R.J. Vašut, 14. V. 2007, OL. 6. Taraxacum quadrans H. Øllgaard Bot. Not. 131: 515, 1978. (Fig. 7) A medium sized plant, 15–25 (–30) cm tall. Leaves dark bluish green, interlobes with or without dark blotch, midrib pink to purple; lateral lobes 3–5 on both sides, regular, recurved, deltoid, rather short, usually acute, with distal margin frequently and characteristically very obtusely angled or at least convex, often filiform dentate, the proximal margin ± straight; terminal lobe medium-sized, triangular to helmet-shaped, blunt, sometimes mucronate, usually entire; petiole unwinged 7. Taraxacum fusciflorum H. Øllgaard Pl. Syst. Evol. 141: 215, 1983. (Fig. 8) A medium sized, sometimes large plant, 15–25 (–30) cm tall. Leaves dull grey-green, interlobes sometimes ± blotched, midrib coloured purple interwoven with green strands; lateral lobes (4–) 5 (–6) on both sides, usually recurved, hamate in outer leaves, obtuse to subacute at apex, with distal margin convex, entire or, in inner leaves, sparsely dentate, the proximal margin most often concave; terminal lobe usually entire, rather small, cordate-sagittate; interlobes entire in outer leaves, dentate in inner leaves; petiole narrow, ± unwinged, pink to purple. Capitulum 4–5 cm in diameter; outer ligules with rather dark coloured strip almost as wide as the ligule; exterior bracts spreading to recurved, 11–14 mm long, (2.5–) 3.0–4.5 mm wide, lanceolate, with slightly revolute margins, with red tip, unbordered, grey-green and pruinose on upper surface, dark green on lower surface; styles discoloured. Achenes with recurved spines, 601 Taraxacum sect. Hamata in Slovakia ment, 49◦ 28′ 06′′ N, 18◦ 52′ 15′′ E, leg. B. Trávníček, 18. V. 2005, OL. Discussion Fig. 8. Herbarium specimen of Taraxacum fusciflorum. (NW Slovakia, Makov, Vršok) Bar = 5 cm. 3.9–4.3 mm long, cone 0.6–0.7 mm long. The species T. fusciflorum was found in NW, N and Central Europe. It was recorded from the following countries: Iceland, Great Britain, Ireland, Germany, Denmark, Finland and the Czech Republic (Øllgaard 1983, 1994; Kirschner & Štěpánek 1995; Dudman & Richards 1997; Sackwitz et al. 1998; Kirschner et al. 2002; Uhlemann 2003). The species was found at a single locality so far. It infrequently grows in ruderal grassy places along the way, as well as in the meadows, similar to the Violion caninae association. We propose to consider species as category “EN” in Slovakia (according to Feráková et al. 2001). Distribution in Slovakia: 28. Západné Beskydy: Vršok settlement WNW of the Makov village, meadows and roadsides near NW margin of the settlement, 49◦ 23′ 13′′ N, 18◦ 24′ 54′′ E, leg. Ľ. Majeský, B. Trávníček & R.J. Vašut, 12. V. 2009, OL. 8. Indeterminable populations We discovered three populations, which we were not able to identify with any already known and described species. The plants shared the morphological key characteristics of the section Hamata, but differed in the character of the leaf-shape and involucrum from that of any other Central European hamate species. The three populations were similar to each other, and were morphologically close to both T. lamprophyllum and T. kernianum Hagendijk, van Soest et Zevenbergen. These populations require further taxonomical and genetic study. Distribution in Slovakia: 28. Západné Beskydy: town of Čadca, Podzávoz suburb, meadow above the suburb 1.5 km NE from Jurošovský vrch hill (630 m), 49◦ 27′ 40′′ N, 18◦ 46′ 26′′ E, B. Trávníček & R.J. Vašut, 8. V. 2003. OL. – Oravská Polhora village near town of Námestovo, small meadows near the Slaná Voda settlement, 49◦ 32′ 48′′ N, 19◦ 28′ 44′′ E, B. Trávníček & R.J. Vašut, 24. V. 2003, OL. – Čadečka village near town of Čadca, lawns and roadsides near Šimčiskovci settle- The distribution of species of Taraxacum sect. Hamata have remarkable sub-oceanic tendencies. At the time of its description, the distribution range of the section was believed to be limited to countries along the North and Baltic sea coast (Øllgaard 1983). More detailed research on dandelions in other European countries has moved the limits of the distribution range of T. sect. Hamata further eastwards. Species of Hamate dandelions have been recorded from other parts of Germany (e.g. Sackwitz et al. 1998; Uhlemann 2003) and from the Czech Republic (e.g. Kirschner & Štěpánek 1995; Kirschner et al. 2002; Trávníček et al. 2010). Before the discovery of hamate dandelions in Slovakia, the eastern limit of the distribution range of the section were in the Moravskoslezské Beskydy Mts. However, while the hamate dandelions are rare in Slovakia, its presence is not surprising. The regions of Kysuce and Orava are known for the presence of several other taxa of suboceanic distribution tendencies, e.g. Lycopodiella inundata (L.) Holub, Lotus uliginosus Schkuhr, Pedicularis sylvatica L. and Juncus squarrosus L. (Dostál 1989). The distribution of section Hamata in Slovakia continues from the Moravskoslezské Beskydy Mts and its foothills, where hamate dandelions grow with a scattered frequency. Going east- and southwards, the frequency of the species and abundance of plants in populations decreases remarkably. In Slovakia, hamate dandelions are those most frequently present in the Kysuce region, and a sparse distribution of the section also exists in the Orava region. More eastwards, the occurrences of hamate dandelions are solitary. We also thoroughly investigated dandelions in neighbouring regions (e.g. the Oravská Magura Mts, Javorníky Mts etc.), and we have found many suitable habitats for T. sect. Hamata. However, none of any of the species were found. In these suitable habitats in this region, species of T. sect. Palustria were often growing; which have greater tendencies toward a continental distribution. We expect that the occurrence of hamate dandelions in more southern regions of Slovakia is unlikely (however, not impossible). Based upon our observations of the frequency of species of T. sect. Hamata in Slovakia, we believe that the region of NW and N Slovakia represents the south-eastern limit of the distribution range in Europe of T. sect. Hamata. However, it is problematic whether or not to include apomictic taxa of dandelions in Red Lists. We propose hamate dandelions to be considered as endangered in Slovakia. We investigated several tens of localities in the field in Slovakia, and hamate dandelions were so far only found on a negligible number of localities. We therefore consider the “picture” of the distribution of section Hamata in Slovakia presented in this paper as very realistic – the section is rare in Slovakia. We suppose that more localities might be found in NW, N 602 or NE regions; however the frequency is expected to be sparse. However rare hamate dandelions are in Slovakia, they are not usually threatened in these localities. Furthermore, suitable habitats are rather frequent in northern Slovakia. Therefore, we see the main reason for the vulnerability of the taxa of T. sect. Hamata is due to the fact that the Slovak localities occur at the border of their geographical distribution range. We therefore propose the taxa of T. sect. Hamata to be considered as category “EN” in Slovakia (according to Feráková et al. 2001). Acknowledgements We wish to thank V. Žíla (Strakonice, Czech Republic) for help in the field finding the T. boekmanii; and H. Øllgaard (Viborg, Denmark) for providing unpublished data on the distribution of Hamate dandelions in Europe. 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