On Hieracium incurrens (Asteraceae) and similar species in central Sweden

Hieracium incurrens Saelan ex Norrl., originally described from Finland, has been reported from Sweden several times and independently by different authors. Still, however, its presence in Sweden has remained dubious and it has become obvious that the different reports are referable to different taxa and the name has thus been, at least partially, misapplied. In the present study, all Swedish material and putative taxa that have been suggested to belong to H. incurrens , as well as some additional closely similar taxa, is critically compared with authentic material of the latter from Finland. It is concluded that H. incurrens do indeed occur in central Sweden, namely in the eastern coastal provinces closest to Finland. However, the relevant material has mostly been referred to H. longilingua Johanss., which is here considered to be a later synonym of H. incurrens. Material previously referred to H. incurrens from other parts of Sweden does, however, represent other taxa. Five accepted species of this affinity are described and discussed in some detail and one species, viz. H. oestmanii T. Tyler is described anew. In addition, the unrelated species H. arnoldii T. Tyler is described anew based on material from the provinces of Hälsingland and Medelpad.     

Eight new species of Hieracium sect. Tridentata (Asteraceae) from southern and northern Sweden

Eight new species of Hieracium sect. Tridentata, namely H. antrorsum, H. quercifolium, H. stenianum, H. vestrogothicum, and H. vetlandaënse are described from the Götaland region (southern Sweden), H. grothii from Norrbotten in the Norrland region (northeast Sweden), and H. sparsifolium var. suppansum Johanss. and H. adampliatum var. pilosius Ohlsén are raised to specific rank as H. suppansum and H. gothiciferum respectively.     

A revision of Hieracium (Asteraceae) in Norrbotten,northeastern‐most Sweden,revealed seven new species

The large quantity of material of Hieracium sectt. Hieracium, Vulgata, Bifida and Oreadea collected during the recently completed floristic inventory of the northeastern most Swedish province of Norrbotten has been revised. The number of species known from this previously badly under‐collected province hereby increased from 27 to 64, and seven species new to science were revealed. A diagnostic key to all 64 species is provided and H. alces T. Tyler, H. hystrix T. Tyler, H. larsii‐levii T. Tyler, H. pseudopsepharum T. Tyler, H. stenbergii T. Tyler, H. taedum T. Tyler and H. vexillatum T. Tyler are described anew.     

Seven new species of Hieracium sect. Tridentata (Asteraceae) from Götaland,southern Sweden

Six new species of Hieracium sect. Tridentata, viz. H. piranhae, H. xanthochlorum, H. bertilssonii, H. erectiramum, H. rigescoides and H. subpardalinum are described from the Götaland region, southern Sweden and H. gothicum var. blekingense is raised to specific rank as H. blekingense.     

Lectotypifications and notes on the application of names of Hieracium sect. Hieracium, sect. Bifida and sect. Vulgata (Asteraceae) based on material from the province of Dalarna, central Sweden

Lectotypes are designated for 174 names of taxa described based on material from the Swedish province of Dalarna and accepted to belong to Hieracium sect. Hieracium , sect. Bifida and sect. Vulgata . The taxonomic and nomenclatural implications, i.e. taxonomic synonyms and infraspecific taxa not worthy of taxonomic recognition, of the lectotypifications are discussed. Three new combinations, H. mundulifolium (Johanss.) T. Tyler, H. oligasterum (Johanss. & Sam.) T. Tyler and H. transtrandense T. Tyler, are proposed to accommodate the infraspecific taxa H. gilvocaniceps Johanss. var. mundulifolium Johanss., H. expallidiforme (Dahlst. ex. Stenstr.) Dahlst. var. oligasterum Johanss. & Sam. and H. insuccatum Johanss. var. occidentale Johanss. & Sam. respectively, when treated at the rank of species.     

Lectotypification of names of south Swedish Hieracium species (Asteraceae)

Ninety-six south Swedish taxa in Hieracium L. sect. Hieracium and H. sect Vulgata (Griseb.) Willk. & Lange are lectotypified. The authorship of each name is analysed and the identity and synonomy of some dubious taxa are discussed.-Flora Nordica Note no. 24     

Three hawkweeds (Hieracium,Asteraceae) from the Netherlands typified and raised to species rank

After a short sketch of Dutch hieraciology, three taxa belonging to Hieracium sectt. Vulgata and Tridentata that were described from the Netherlands at the rank of subspecies or variety by Zahn are typified and raised to species rank. Hieracium meppelense (Zahn) Haveman comb. et stat nov. is found in the province of Drenthe in the northeastern part of the country, H. limburgense (Zahn) Haveman comb. et stat nov. in south‐Limburg in the southernmost part and H. macrodontophyllum (Van Soest et Zahn) Haveman comb. et stat nov. in the surroundings of Nijmegen and Arnhem, and further north in the central sand area. Photographs of the types as well as maps with the hitherto known distribution of these three species are included.     

Nomenclature of members of Hieracium sectt. Alpestria,Foliosa and Prenanthoidea (Asteraceae) reported from Sweden

Names of taxa referred to Hieracium sectt. Alpestria (including the ‘Semidovrensia group’), Foliosa and Prenanthoidea and reported from Sweden have been compiled from the literature and herbaria and all uses have been indexed. Based on this synopsis, the nomenclatural validity and legitimacy of the names are analysed. In total, the use of 75, 62 and 27 names is documented for the three sections, respectively, but it is concluded that only 37, 31 and 13 of these are validly published with available combinations at the rank of species. Whenever these sections are to be revised taxonomically, a large number of new combinations will thus have to be proposed.     

The tubarium construction of Lower Ordovician (Dapingian) Baltograptus species (Graptolithina) from Dalarna,Sweden

Isolated and chemically bleached graptolite specimens of Baltograptus from Skattungbyn, Dalarna (central Sweden), reveal important new information on the internal construction of the tubarium. The specimens show the typical metasicular origin of th1¹ and the presence of numerous longitudinal rods in the prosicula. The investigation provides some insight into intraspecific variation and on the differentiation of individual species. It also provides information on the early evolution of the two‐stiped dichograptids. Three distinct species, identified as Baltograptus minutus (Törnquist) B. kurcki (Törnquist) and B. extremus sp. nov. can be recognized in the collection of hundreds of specimens. The Baltograptus species are associated with a diverse Dapingian graptolite fauna, prepared by Roland Skoglund, but never investigated in detail, including specimens of Pseudophyllograptus densus, Acrograptus gracilis and other taxonomically and biostratigraphically important taxa.     

Hieracium vierhapperi (Asteraceae) a new species to the Carpathians, with some remarks on its origin

Hieracium vierhapperi (Zahn) Szeląg, known so far only from the Alps, was discovered in the Nízke Tatry Mts in Slovakia, as a new species to the Carpathians. Diagnostic characters, illustration and distribution as well as ecology of H. vierhapperi in the Nízke Tatry Mts are given. A key to distinguish H. vierhapperi from the morphologically related species is added. The Carpathian plants are tetraploid (2n = 36) and reproduce apomictically. The origin of H. sect. Cernua R. Uechtr in the Western Carpathians is briefly discussed.     

Hieracium busambarense,a new species of the sect. Grovesiana (Asteraceae) from Sicily (Italy)

Hieracium busambarense (Asteraceae), a new species from calcareous-dolomite cliffs of Rocca Busambra (western Sicily, Italy) is described and illustrated here.     

A new diploid species of Hieracium sect. Pannosa (Asteraceae) from Bulgaria

Hieracium petrovae Vladimirov & Szeląg sp. nov. , a new diploid (2 n  = 18) species in H. sect. Pannosa Zahn, is described and illustrated from the Rhodope Mountains, South Bulgaria, and compared with related taxa. It grows in relict habitats in crevices of limestone rock together with many Balkan endemics. H. petrovae is morphologically similar to taxa from the H. pannosum , H. pilosissimum and H. heldreichii groups (collective species sensu Zahn) to some of which it is a presumed ancestral species.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 261–265.     

Cytotype distribution and phylogeography of Hieracium intybaceum (Asteraceae)

Using flow cytometry and amplified fragment length polymorphism (AFLP), we explored the cytogeography and phylogeography of Hieracium intybaceum, a silicicolous species distributed in the Alps and spatially isolated in the Vosges Mountains and the Schwarzwald Mountains. We detected two ploidies, diploid and tetraploid, but no triploid or mixed‐ploidy populations. Whereas diploids are sexual and distributed all across the Alps, tetraploids are apomictic and seem to be confined to the western Alps and the Vosges. We detected a low level of genetic variation. Bayesian clustering identified four clusters/genetic groups, which are partly congruent with the ploidal pattern. The first two groups consisting exclusively of diploids dominate the whole distribution range in the Alps and show east–west geographical separation with a diffuse borderline running from eastern Switzerland to the eastern part of North Tyrol. The third genetic group lacks a defined geographical range and includes diploid and tetraploid plants. The last genetic group comprises tetraploid plants in the French Alps and the Vosges. We suppose that diploids colonized the deglaciated areas from source populations most likely located mainly in the southern part of the recent distribution range and occasionally also in the western Alps. Gene flow and further differentiation likely took place. Apomictic tetraploids most likely originated in the western Alps or in the refugium at the south‐western foot of the Alps. Their rather limited geographical range (partly contrasting with the theory of geographical parthenogenesis) can be explained by their rather recent origin. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 487–498.     

Increased litter decomposition rates of exotic invasive species Hieracium pilosella (Asteraceae) in Southern Patagonia,Argentina

Plant Ecology - Plant invasions can affect key ecosystem processes regulating carbon and nutrient balances, i.e., litter decomposition. Exotic herb Hieracium pilosella (hawkweed, Asteraceae)...     

Hieracium sect. Oreadea (Asteraceae) in Sweden – from a complete mess to a preliminary taxonomic classification

Among Swedish Hieracium sect. Oreadea (Fr.) Arv.‐Touv., more than 100 taxa have been recognized by various experts but, except for a regional monograph from 1894 there are no thorough published revisions of the group and many of the names have never been validly published. At the same time, some of the oldest names have been variously applied to morphologically clearly different species. In the present study, 5000 specimens in Swedish herbaria have been revised using both traditional and statistical morphometric methods and the complicated nomenclature has been disentangled. Twenty‐eight species are recognized and described with diagnostic keys and illustrations aiding identification and their known distributions are mapped. Six species are described as new to science (viz. H. marinum T. Tyler, H. eulasium Dahlst. ex T. Tyler, H. victoriae T. Tyler, H. falcifolium Johanss. ex T. Tyler, H. guldbergense Folin ex T. Tyler and H. hispidosum Dahlst. ex T. Tyler) and 3 additional names are raised to the specific rank (viz. H. gigantocybe (Dahlst.) T. Tyler, H. hilare (Dahlst. ex Omang) T. Tyler and H. tanyphyllum (Dahlst. ex Zahn) T. Tyler). Lectotypes are designated for 50 names based on material from Sweden, Norway or Finland and one name is neotypified. Except for a few infraspecific names for which all original material appears to be lost, all names based on material from Sweden are typified. However, it is concluded that albeit the number of taxa is relatively low, the species of H. sect. Oreadea are morphologically less distinct and clear‐cut than those of other widespread Scandinavian sections of the genus. Many of the characters that are most important in other sections of the genus are either invariable or unreliable in H. sect. Oreadea. Thus, the taxonomy has to rely on characters more subjected to environmentally‐induced modification. Furthermore, members of this section exhibit great morphological plasticity, possibly connected to their preference for exposed rocky habitats where the environmental conditions may be both severe and unpredictable.In addition, due to their ecological demands, they are confined to habitats that have always been both strongly fragmented and restricted in size giving rise to multiple small and locally adapted local populations. The section is here circumscribed in agreement with previous Scandinavian authors, i.e. including both the H. schmidtii‐group sometimes referred to H. sect. Stelligera and the H. norvegicum group approaching H. sect. Tridentata, but it is concluded that the section is relatively heterogeneous and that further studies aiming at the identification of more natural supraspecific taxa are much needed.     

In vitro allelopathic effects of pollen from three Hieracium species (Asteraceae) and pollen transfer to sympatric Fabaceae

Pollen allelopathy occurs when pollen toxins inhibit sexual reproduction in heterospecifics. To quantify pollen allelopathic effects in vitro, pollen of Hieracium aurantiacum, H. floribundum, and H. pratense was extracted with double distilled water into concentrations of 0 (control), 0.1, 1, 3, 5, 10, and 25 pollen grains/μl. A subset of these extracts was partitioned by ion-exchange chromatography into acidic, basic, and neutral fractions. Pollen from six sympatric species of Fabaceae (Lotus corniculatus, Medicago sativa, Trifolium hybridum, T. pratense, T. repens, Vicia cracca) and the species of Hieracium was germinated on agar media containing different extract concentrations. As extract concentrations from intact pollen or from acidic fractions increased, mean percent germination of pollen of all Fabaceae decreased nonlinearly. Extract concentrations of 0.1 grains/μl and above inhibited pollen germination in the Fabaceae. In no case was any Hieracium species affected, i.e., there was no autotoxicity. Similar results were obtained using plants from nine populations of H. floribundum and H. pratense across eastern Canada. Observation of floral visitors indicated that there were relatively few movements between Hieracium and the Fabaceae (about 15% of total visits). Hence there is limited opportunity for heterospecific pollen transfer. This was consistent with censuses of stigma, i.e., few pollen grains of Hieracium were found on stigma of the Fabaceae. Thus, pollen allelopathy in Hieracium is unlikely to affect reproductive success in these six species of Fabaceae.     

Chromosome numbers in Hieracium and Pilosella species (Asteraceae) from the Iberian Peninsula and the Balearic Islands

Mitotic chromosome numbers are reported from 16 Hieracium and two Pilosella species from the Iberian Peninsula and the Balearic Islands that are little known cytogenetically. The chromosome numbers of Hieracium aragonense Scheele (2 n  = 27, 36), H. compositum Lapeyr. (2 n  = 27), H. murcandidum G. Mateo (2 n  = 27), H. spathulatum Scheele (2 n  = 27), H. segurae Mateo (2 n  = 27), H. teruelanum Mateo (2 n  = 27), H. valentinum Pau (2 n  = 27), Pilosella pseudovahlii (De Retz) Mateo (2 n  = 18), and P. tardans (Peter) Sójak (2 n  = 36) were determined for the first time. New cytotypes were detected in H. cordifolium Lapeyr. (2 n  = 27) and H. loscosianum Scheele (2 n  = 36). The karyotype of the studied species was similar in overall morphology and comprised metacentric and submetacentric chromosomes; secondary constrictions (up to two) were detected in the chromosome complements of some species.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 311–320.     

Pollen and chromosome studies in Hieracium sect. Alpestria (Asteraceae)

Potential pollen viability has been investigated in British apomictic Hieracium section Alpestria and related species using Alexander's Stain. New and existing chromosome counts are given. Some species produced no pollen, others varied in the amount they produced, and a few species consistently produced reasonable quantities. The three triploid section Alpestria species produced very little or no pollen, whilst the amount produced by the tetraploids varied widely. Section Alpestria species had significantly lower pollen viability than the non‐section Alpestria species. The generally low pollen production in most species of section Alpestria is consistent with them being of hybrid origin.     

Genome size variation and species relationships in Hieracium sub-genus Pilosella (Asteraceae) as inferred by flow cytometry

BACKGROUND AND AIMS: Hieracium sub-genus Pilosella (hawkweeds) is a taxonomically complicated group of vascular plants, the structure of which is substantially influenced by frequent interspecific hybridization and polyploidization. Two kinds of species, 'basic' and 'intermediate' (i.e. hybridogenous), are usually recognized. In this study, genome size variation was investigated in a representative set of Central European hawkweeds in order to assess the value of such a data set for species delineation and inference of evolutionary relationships. METHODS: Holoploid and monoploid genome sizes (C- and Cx-values) were determined using propidium iodide flow cytometry for 376 homogeneously cultivated individuals of Hieracium sub-genus Pilosella, including 24 species (271 individuals), five recent natural hybrids (seven individuals) and experimental F(1) hybrids from four parental combinations (98 individuals). Chromosome counts were available for more than half of the plant accessions. Base composition (proportion of AT/GC bases) was cytometrically estimated in 73 individuals. KEY RESULTS: Seven different ploidy levels (2x-8x) were detected, with intraspecific ploidy polymorphism (up to four different cytotypes) occurring in 11 wild species. Mean 2C-values varied approx. 4.3-fold from 3.53 pg in diploid H. hoppeanum to 15.30 pg in octoploid H. brachiatum. 1Cx-values ranged from 1.72 pg in H. pilosella to 2.16 pg in H. echioides (1.26-fold). The DNA content of (high) polyploids was usually proportional to the DNA values of their diploid/low polyploid counterparts, indicating lack of processes altering genome size (i.e. genome down-sizing). Most species showed constant nuclear DNA amounts, exceptions being three hybridogenous taxa, in which introgressive hybridization was suggested as a presumable trigger for genome size variation. Monoploid genome sizes of hybridogenous species were always between the corresponding values of their putative parents. In addition, there was a good congruency between actual DNA estimates and theoretical values inferred from putative parental combinations and between DNA values of experimental F(1) hybrids and corresponding established hybridogenous taxa. CONCLUSIONS: Significant differences in genome size between hawkweed species from hybridogenous lineages involving the small-genome H. pilosella document the usefulness of nuclear DNA content as a supportive marker for reliable delineation of several of the most problematic taxa in Hieracium sub-genus Pilosella (including classification of borderline morphotypes). In addition, genome size data were shown to have a good predictive value for inferring evolutionary relationships and genome constitution (i.e. putative parental combinations) in hybridogenous species.     

Chloroplast DNA diversity of Hieracium Pilosella (Asteraceae) introduced to New Zealand: reticulation, hybridization, and invasion

The European hawkweed Hieracium pilosella is a successful invader and a troublesome weed in New Zealand. The systematics of the genus Hieracium is extremely complex and contentious, probably due to recent speciation, hybridization, polyploidy, and diverse reproductive strategies. In the first chloroplast DNA survey of the group, we sequenced 285 plants (including H. pilosella and 12 other species of subgenus Pilosella) from New Zealand and Europe for 900 bp of trnL-trnF. Eleven haplotypes were identified with much sharing among species. Three haplotypes (A, D, G) were found in seven, three, and four species, respectively, but two species (H. lactucella and H. auricula) had single, private haplotypes. Our cpDNA data for subgenus Pilosella are consistent with the group's having incomplete lineage sorting and/or recent reticulate evolution. Six haplotypes were identified in H. pilosella, four of these unique to this taxon in our sample. In New Zealand, haplotype A was common and occurred in plants of different ploidy (i.e., 4×, 5×, 6×), whereas haplotypes C, B, and M were restricted to 4×, 5×, and 6× plants, respectively. The distribution of haplotype variation suggests that some or all of the H. pilosella seeds accidentally introduced into New Zealand probably came from east Europe rather than the United Kingdom and that a minimum of four lineages were introduced. Within New Zealand, hybridization of H. pilosella with a related taxon (probably H. praealtum) has occurred at least three times, involving both obligate sexual tetraploids and facultative apomictic pentaploids of H. pilosella.