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.
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.