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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...
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New distribution data of Taraxacum cristatum (T. scanicum group), described in the year 2005, in Slovakia were recorded. During the intensive study of Slovak dandelions in herbarium collections and field course, additional 22 localities were found. The species has been recorded in 17 phytogeographical districts up to now, with the highest frequency...
It is known from many studies that plant species show a delay in the timing of flowering events with an increase in latitude and altitude, and an advance with an increase in temperature. Furthermore, in many locations and for many species, flowering dates have advanced over the long-term. New insights using survival modeling are given based on data...
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... La mayoría de las especies apomícticas tienen una distribución restringida (Richards, 2003, Silvertown, 2008 pero ligada a la acción antrópica gracias a características ecológicas muy amplias. Además, pueden cruzarse con otras produciendo nuevos linajes hibridógenos que dan lugar a plantas con una morfología muy variada de difícil identificación (Vašut, 2003), pudiendo contener caracteres incluso de distintas secciones (Trávníček & Vašut, 2011, Štěpánek & Kirschner, 2022, aunque la constancia existente en la estructura de las hojas, las brácteas externas del capítulo y los frutos, permite diferenciar a las especies. ...
... La sección Hamata se caracteriza por los lóbulos laterales de las hojas frecuentemente hamatos, con el borde distal convexo, brácteas externas del capítulo glaucas, pruinosas, rara vez con un callo o cuerno subapical, recurvadas ya en el botón floral, a veces marginadas y aquenios de color marrón o pajizo con el cono sin espículos (Trávníček & Vašut, 2011, Richards, 2012. Las especies de la sección Celtica presentan los lóbulos laterales de las hojas deltoideos, con el borde distal recto, ligeramente convexo o sigmoideo, y el pecíolo y nervio medio estriado, a menudo purpúreos, brácteas externas del capítulo glaucas o de un verde oliva aunque teñidas de púrpura, a veces con una pequeña callosidad subapical, de adpresas a recurvadas en el botón floral, frecuentemente marginadas y aquenios de color marrón o verde oliva con el cono rara vez espiculado (Richards, 1985, Dudman & Richards, 1997. ...
... Las localidades de la Península Ibérica constituyen una novedad corológica y una ampliación de su área al centro de España. La hemos encontrado en céspedes artificiales, pero ocupando una posición ombrófila y húmeda casi debajo de los setos, tal como otros autores la señalan en otros lugares de Europa (Dudman & Richards, 1997, Trávníček & Vašut, 2011, Matysiak et al., 2014. Se caracteriza por sus hojas con el pecíolo y nervio medio estriado longitudinalmente, el pecíolo frecuentemente alado y purpúreo, y el nervio medio verde, aunque a menudo purpúreo hacia la base, con los lóbulos hamatos o deltoideos, por lo general dentados en el margen distal. ...
Taraxacum boekmanii Borgv. and T. subhamatum M.P. Christ. are reported for the first time in Spain, and T. pinto-silvae Soest in Gredos mountains (Avila). For each of them, taxonomic characters with supplementary pictures are provided.
... In May 2020, in connection with a project to familiarize myself with the nonnative dandelions (Taraxacum F. H. Wigg.) in the flora of Vermont, I encountered a population of a very distinctive dandelion in a meadow in Hardwick, Caledonia County. Upon study with relevant literature and illustrations (Dudman and Richards 1997;Richards 2012;Richards and Sell 1976;Stace 2019;Trávníček and Vašut 2011), I determined it to be T. hamatum Raunk. (Figure 1). ...
... An image of the lectotype specimen was published by Øllgaard (1983); an image of a duplicate (S10-38037) is available on JSTOR Global Plants (2020). Excellent illustrations may be found in Dudman and Richards (1997), Richards (2012), and Trávníček and Vašut (2011). ...
... Taraxacum hamatum, the hook-lobed dandelion, occurs across western Europe (Composite Working Group 2020; Kilian et al. 2009+;Kirschner et al. 2007+) in Belgium, Great Britain, Czech Republic, Denmark, Finland, France, Germany, Ireland, Holland, Poland, northwestern European Russia, and Sweden. It has also been reported from Slovakia (Trávníček and Vašut 2011) and from Madeira, where it is doubtfully native (Kirschner et al. 2007+). In North America, it has been recently reported from British Columbia, Canada (Björk 2019), the only report from this continent. ...
... At the section level, they are assigned to habitats of varying moisture and fertility (e.g. Štěpanek 1998, Trávníček andVašut 2011). As demonstrated by some more detailed observations, individual microspecies within a section may be indicative of the grassland management type and short-term environmental improvement or deteriorations (Oosterveld 1978(Oosterveld , 1983. ...
... Dandelions of each section are found under a specific set of environmental conditions; for example, microspecies from the section Palustria are almost exclusively confined to natural and semi-natural habitats and are usually found in periodically flooded sites, with an accompanying effect of new minerals available from the sediments (Kirschner and Štěpanek 1998, Schmid 2002, Marciniuk 2012; microspecies from the section Celtica prefer plots under relatively low organic manuring and are found in meadows, pastures, as well as along roads in urban areas (Horn et al. 1996, Trávníček et al. 2010; microspecies from the section Taraxacum (Ruderalia) prefer regularly fertilized grasslands and various anthropogenic habitats; as the summer habitat dry-out is probably the main factor limiting their occurrence, they are often found in areas affected by the maritime climate (Sterk et al. 1983, Trávníček et al. 2010; microspecies from the section Hamata are usually found in moist meadows, preferably with lower pH, an intermediate mineral content and a partly disturbed vegetation, as well as in shaded places in urban areas (Øllgaard 1983, Trávníček andVašut 2011). Oosterveld (1983) conducted one of the few direct studies on the ecological preferences (involving soil properties) of individual dandelion microspecies. ...
The vegetation of protected salt meadows along the Baltic coast is fairly well known; however, dandelions have been so far treated as a collective species. The aim of our study was to examine the microspecies diversity of the genus Taraxacum in Polish salt and brackish coastal meadows and to analyse soil property preferences of the dandelion microspecies identified. In addition, we analysed the relations between soil properties and vegetation patterns in dandelion-supporting coastal meadows (by canonical correspondence analysis). The salt and brackish meadows along the Polish Baltic coast we visited were found to support a total of 27 dandelion microspecies representing 5 sections. Analysis of vegetation patterns showed all the soil parameters (C:N ratio, organic matter content, pH, concentration of Mg, P, K, electrolytic conductivity of the saturated soil extract EC e ) to explain 32.07% of the total variance in the species data. The maximum abundance of most dandelion microspecies was associated with the highest soil fertility, moderate pH values and organic matter content, and with the lowest magnesium content and soil salinity. The exceptions were T. latissimum, T. stenoglossum, T. pulchrifolium and T. lucidum the occurrence of which was related to the lowest soil fertility and the highest salinity. In addition, several microspecies (T. leptodon, T. gentile, T. haematicum, T. fusciflorum and T. balticum) were observed at moderate C:N ratios and ECe. Four other microspecies (T. infestum, T. cordatum, T. hamatum, T. sertatum) occurred at the lowest pH and organic matter content. The information obtained increases the still insufficient body of knowledge on ecological spectra of individual dandelion microspecies, hence their potential indicator properties.
... 55 sections (KIRSCHNER & ŠTĚPÁNEK 1997). According to TRÁVNÍČEK & VAŠUT (2011) ancestral sections comprise only a few species and these are usually diploid sexuals (e.g. sections Piesis, Dioszegia, etc.). ...
Historical and recent occurrence of a rare dandelion Taraxacum serotinum (Waldst. et Kit.) Fisch. in the area of Slovakia was studied. Herbarium specimens deposited in 16 herbaria were revised and field research during 2009–2015 was carried. In total, 76 localities were recorded, but only 16 sites have been confirmed
or newly found at the present. Taraxacum serotinum is recently considered as an endangered species (EN) of the Slovak flora. Distribution map of the historical and recent locations of the species is given.
Taraxacum danubium is xerothermic species of Taraxacum sect. Erythrosperma occurring in Central Europe with the highest frequency in southeastern Czechia, northeastern Austria and southwestern Slovakia. Since its description in 1970 from Devínska Kobyla Hills in Slovakia the species was documented from numerous localities across the country, however overall study on the species distribution in Slovakia was still lacking. Thus in this paper, we present a detailed survey on its chorology in Slovakia based on our long-term field observation and data excerption from herbarium specimens with commentary on the distribution (over 60 localities in Slovakia) and biology of the species. Western Slovakia seems to be a centre of its distribution, while towards east the number of populations rapidly decreases. Karyology and ecology are discussed. The full list of locations and distribution map are presented.
Florivores directly decrease the reproductive success of plants by consuming pollen and seeds; thus, plants often have defense mechanisms against florivory. Here, we show that the recurved phyllaries of an agamospermous hybrid dandelion, Taraxacum japonicum × officinale, function as a physical barrier to slug florivory. We allowed Lehmannia valentiana, a European slug naturalized in Japan, to feed on eight pairs of the hybrid dandelion and T. japonicum, a Japanese species with erect phyllaries. Consequently, the slugs only damaged T. platycarpum flowers. The slugs either moved back from recurved phyllaries or spent more than twice as long on recurved than on erect phyllaries. When we removed the recurved phyllaries, the slugs stayed on hybrid and T. japonicum phyllaries for equal lengths of time. In addition to recurved outer phyllaries, the hybrid dandelion has erect inner phyllaries that are longer than those of T. japonicum, which effectively conceal the florets at night protecting them from slug florivory. Using the taxonomic literature, we have confirmed that recurved phyllaries evolved in many species in several parts of Europe, but are rare in East Asia. These findings suggest that European dandelions acquired recurved phyllaries as a defense mechanism under antagonistic coevolution with florivorous slugs, but this coevolution did not occur in East Asia.
New localities of taxa of Taraxacum sect. Erythrosperma (Cichorioideae, Asteraceae) were recorded in the lowland region Východoslovenská nížina; five taxa from the sect. Erythrosperma were noted: Taraxacum bellicum (3 localities), T. cristatum (1 locality), T. danubium (1 locality), T. erythrospermum (8 localities), T. parnassicum (1 locality), and 1 form with grey achenes: T. erythrospermum f. achyrocarpum (8 localities).
Keywords: apomixis, Asteraceae, cytometry, dandelions, taxonomy, Slovakia
The genus Taraxacum sect. Erythrosperma is represented by one diploid species and several triploid microspecies in the territory of Slovakia. In comparison with the sect. Ruderalia it is not widespread and its occurrence is limited to areas with xerophilous and thermophilous vegetation. Besides some morphological characters on leaves particular microspecies within the section Erythrosperma differ by position and size of outer bracts as well as size and colour of achenes. Morphometric analyses with employment of multivariate statistic methods in the sample of 745 achenes and 447 outer bracts showed no substantial differences in the studied characters between diploid Taraxacum erythrospermum and triploids (T. cristatum, T. danubium, T. prunicolor). In the case of analysis of sole triploid microspecies, these microspecies can be distinguished from each other on the basis of characters on achenes and outer bracts quite well. These characters, when combined with other morphological characters, can play an important role in determination of particular taxa.
