Multivariate morphometrics and an assessment of genetic diversity obtained using amplified fragment length polymorphism (AFLP) were used to determine the variability of the polymorphic group Cyanus triumfetti in Central Europe. The ploidy level of the populations studied was also determined; all individuals from the C. triumfetti group were diploid (2n ~ 2x ~ 22) and all those of the related C. montanus group were tetraploid (2n ~ 4x ~ 44). A multivariate morphometric study of 71 populations revealed that three species from the C. triumfetti group occur in Central Europe, namely ‘Cyanus axillaris’, C. strictus and C. dominii. Three subspecies are recognized within the latter species, namely C. dominii subsp. dominii, C. dominii subsp. slovenicus and C. dominii subsp. sokolensis. Morphological characters of leaves are the best features for delimiting these taxa; a shift in characters caused by cultivation did not affect the value of key characters and differences among the taxa remained. AFLP analysis of 38 populations from the C. triumfetti group and two from the C. montanus group revealed a contrasting pattern of genetic variation that was related to the geographic distribution of the populations rather than the morphological variation in the C. triumfetti group. The AFLP data revealed the following three genetically differentiated and allopatric groups: (i) C. triumfetti s.s. and C. montanus from the Western Alps, (ii) ‘C. axillaris’ from Austria and the Czech Republic (except the Carpathians) and (iii) ‘C. axillaris’, C. strictus and C. dominii from the Western Carpathians and Pannonia. The striking genetic gap between the Austrian-Czech and the W Carpathian-Pannonia groups and the high genetic diversity and weak genetic differentiation within the latter group are discussed in the light of potential glacial refuges, postglacial migration routes and/or the probability of hybridization events occurring during the evolutionary history of this group. An identification key for the taxa of the C. triumfetti group in Central Europe is presented.
Chromosome numbers of 23 species (including subspecies) of Hieracium s. str. from the Western Carpathians are presented. First chromosome numbers are reported for Hieracium kuekenthalianum (= H. tephrosoma, 2n = 36), H. praecurrens (2n = 27) and H. virgicaule (2n = 27); first counts from the Western Carpathians are given for H. atratum (2n = 27), H. bifidum (2n = 27, 36), H. carpathicum (2n = 36), H. inuloides (2n = 27), H. jurassicum (2n = 27), H. macilentum (= H. epimedium, 2n = 27), H. nigritum (2n = 36), H. pilosum (= H. morisianum, 2n = 27) and H. silesiacum (2n = 36). New ploidy level (tetraploid, 2n = 36) is reported for H. bupleuroides, hitherto published counts refer only to triploids (2n = 27). Previously published chromosome numbers were confirmed for several other species, i.e. H. alpinum (s.str., 2n = 27), H. bupleuroides (2n = 27), H. crassipedipilum (H. fritzei group, 2n = 27, 36), H. lachenalii (2n = 27), H. murorum (2n = 27), H. prenanthoides (2n = 27), H. racemosum (2n = 27), H. sabaudum (2n = 27), H. slovacum (H. fritzei group, 2n = 36), and H. umbellatum (2n = 18). Triploids and tetraploids predominate, diploids (2n = 18) were found in H. umbellatum. A comprehensive list of previously published chromosome numbers in Hieracium s. str. from the Western Carpathians is provided.
Conyza bonariensis (L.) Cronquist and C. triloba Decne. are reported as new alien species to the Czech Republic and Europe, respectively. Conyza bonariensis was collected in 1964 and 1965 in two localities in N Bohemia; the specimens are deposited in PRA. In both cases, the plants were introduced with cotton and occurred in areas of textile factories. Conyza triloba was collected once at the pond in the village of Černivsko in S Bohemia in 1971; the specimen is deposited in PR. The mode of introduction is unknown.
Populations of the specialist gall-forming fly, Urophora cardui (Diptera: Tephritidae), were studied at the western and eastern margins of its distribution. In western Europe U. cardui attacks the creeping thistle Cirsium arvense, whereas in eastern Europe, in the Ural mountains, it attacks Cirsium setosum, a taxon closely related to C. arvense. Gall densities are high in the Ural mountains and can be predicted by environmental variables. Compared to galls on C. arvense, those on C. setosum are on average larger. This indicates better performance of U. cardui on C. setosum in terms of cell numbers per gall. Despite the wide distribution of U. cardui, the dominant parasitoids are the same at the western and eastern ends of its distribution and the interactions between parasitoids and the host are similar. In general, we suggest that the synchronisation between the host plant species, the phytophage and the parasitoids is an important factor in the spatial ecology and evolution of this food web.
Six populations of Hieracium echioides subsp. echioides var. tauscheri from the Danube Basin between Bratislava and Budapest (locations: Balinka, Čenkov, Devín, Dorog, Győr, Pilis) were analysed using allozyme and karyological analysis. Five allozyme systems (EST, LAP, 6PGDH, PGM, and SKDH) were used to analyse the genetic structure of the examined populations. Analyses revealed low genetic variation both within- and among populations. Four multilocus allozyme phenotypes were detected; three populations (Čenkov, Devín and Győr) possessed phenotype I exclusively, while phenotype II was found only in the Balinka and Dorog populations. Two different phenotypes were found in the population of Pilis (phenotypes III and IV). However, due to the complex banding patterns generated for EST, allelic interpretationwas not possible, and the Balinka and Dorog populations appeared to possess different phenotypes. All populations proved to be tetraploid (2n = 36) and agamospermous. The geographic distribution pattern of the analysed populations (one allozyme phenotype at several isolated localities) may reflect a more common occurrence of the taxon in the past. Landscape changes, caused by changes in human management of the country, may have resulted in a loss of suitable localities, mainly open sandy habitats. These changes may have caused the reduction and fragmentation of H. *tauscheri habitat.
Examples of Taraxacum species (sect. Ruderalia) that have a well-known main distribution area and, a few rather isolated, obviously introduced occurrences, are given. The lack of a long tradition of specific knowledge and collection of Taraxacum sect. Ruderalia specimens have impeded our understanding of the origin of the present distributions. Some views are presented. Taraxacum ancistratum, T. crassum, T. deltoidifrons, T. infuscatum, T. jugiferum, and T. lundense, all belonging to Taraxacum sect. Ruderalia, are described as new species. Three or four of these species were first found as introductions far away from their supposed main distribution area.
A long-standing problem with the taxonomic status and synonymy of the names Taraxacum nigricans (Kit.) Reichenb. and T. alpestre (Tausch) DC. is resolved. These two names, the oldest ones referable to high mountain dandelions in Central Europe, are typified, and a detailed comparison of these species’ morphology, genotype make-up, karyotypes and distribution is provided, together with a discussion of other cases of similar and probably closely related agamospermous taxa of Taraxacum and Hieracium. Taraxacum nigricans (2n = 32) and T. alpestre (2n = 32) are endemic to the Nízke Tatry Mts, Slovakia, and the Krkonoše/Karkonosze Mts, Czech Republic/ Poland, respectively. These are shown to differ in a series of minor but constant morphological, allozyme and karyotype features, and their treatment as separate agamospermous species is supported. A detailed analysis of cultivated and wild material from the Carpathians revealed the existence of a sexual taxon very close to the above two species and endemic to the region of the Bucegi Mts, Romania. It is described as a new species, T. carpaticum Štěpánek et Kirschner. Two new agamospermous species, apparently allied to T. nigricans, are described: T. rupicaprae Štěpánek et Kirschner, a species characterized by orange-ochraceous achenes and confined to the High Tatra Mts, and T. elegantissimum Štěpánek et Kirschner (2n = 24), which has substantially broader outer bracts and is known from the Rodna, Retezat and Fagaras Mts, Romania. Another three species are described that are morphological similar to T. carpaticum: T. pastorum (the Fagaras Mts, Romania), T. iucundum (the Retezat Mts, Romania) and T. pseudoalpestre (the Fagaras Mts, Romania).
Dandelions (Taraxacum) of the section Erythrosperma were studied in Moravia, Czech Republic, where both sexual diploid and apomictic polyploid species occur. Diploid species T. erythrospermum grows in the warmest part of southern Moravia and is confined to natural dry grasslands, whereas some apomictic species have ranges extending up to the submontane regions and prefer ruderal habits. Altogether, 21 apomictic types were found repeatedly but only seven were identified as previously described species: T. arcuatum, T. danubium, T. lacistophylloides, T. parnassicum, T. plumbeum, T. proximum and T. scanicum. Descriptions, notes on variation and distribution in Moravia, dot maps and pictures are given for eight species.
The present paper summarizes the results of research of Hieracium subgen. Pilosella done by using different methods. The apomictic complex of Hieracium subgen. Pilosella found in the Krkonoše Mts, consists of the following basic species: H. lactucella (2x, sexual), H. onegense (2x, sexual), H. pilosella (4x, sexual), H. caespitosum (4x, apomictic) and H. aurantiacum (4x and 5x, apomictic). These species are considered to be the parents of a further set of mostly apomictic hybridogenous types. The ploidy level, breeding system, isozyme phenotypes, chloroplast haplotypes and geographic distribution of this whole complex was analysed. The different hybridogenous types have different frequencies in the field and differ in the frequency of isozyme phenotypes (a conservative estimate of the number of genotypes). Most have uniform chloroplast haplotypes, but some haplotypes could have originated from reciprocal crosses. The comparison of chloroplast haplotypes suggests that apomictic species were not only pollen donors, but also contributed seed and gave rise to several hybridogenous types, illustrating the importance of the residual sexuality of apomicts in this group. H. pilosella is a central species in this group and is connected with other parental species, H. floribundum, H. lactucella and H. aurantiacum by a set of hybridogenous species that have a similar genetic structure. Some of the distinct hybridogenous types within the complex are of multiple origin. In contrast, crosses between the same parental types may generate diverse progenies, which can often be classified as distinct taxa. All taxa recorded in the past are surveyed and discussed with respect to present knowledge. We suggest that the taxonomy and origin of particular entities of this and other such complexes is best resolved using information from morphological, genetical, cytological and ecological studies.
A population of a hybrid between Tragopogon porrifolius and T. pratensis (T. ×mirabilis), which occurs in SW part of the town of Roudnice nad Labem, N part of Central Bohemia, was analysed with respect to its morphology, fertility, life history, ploidy level and DNA content. Both parental species vary relatively little morphologically; they are biennials (monocarpic perennials) and diploids. T. pratensis is a native species in the Czech Republic, T. porrifolius was cultivated there in the past. The hybrid plants are extremely morphologically variable, with variation ranges of some characters overlapping those of the parental species (e.g. ligules are often longer than involucral bracts, peduncles are often lanate). Only diploids were found within the hybrid population; however, they have substantially lower DNA content than both parents (18% lower than T. pratensis, 42% lower than T. porrifolius). The plants of the Roudnice hybrid population are polycarpic perennials in contrast to the monocarpic perennial (mostly biennial) parents. The distribution is described in detail; it shows that the hybrid plants are spreading and at present even occur outside the town. The long-persisting population of fertile diploid hybrid plants in Roudnice nad Labem is an alternative evolutionary pathway to that of the allotetraploid Tragopogon species known from North America.