Chromosome numbers (ploidy levels) were recorded in the following 25 taxa of Hieracium subgen. Pilosella: H. arvicola Nägeli et Peter (2n = 45), H. aurantiacum L. (2n = 36, 45), H. bauhini Besser (2n = 36, 45), H. bifurcum M. Bieb. (2n = 45), H. brachiatum Bertol. ex DC. (2n = 36, 45), H. caespitosum Dumort. (2n = 36), H. cymosum L. (2n ~ 4x), H. densiflorum Tausch (2n = 36, ~ 4x), H. echioides Lumn. (2n = 18, 45), H. fallacinum F. W. Schultz (2n = 36, 45), H. floribundum Wimm. et Grab. (2n = 36, ~ 4x, 45,), H. glomeratum Froel. in DC. (2n = 45), H. iseranum Uechtr. (2n = 36), H. kalksburgense Wiesb. (2n ~ 5x), H. lactucella Wallr. (2n = 18), H. macranthum (Ten.) Ten. (2n = 18), H. onegense (Norrl.) Norrl. (2n = 18), H. pilosella L. (2n = 36, 45, 54), H. piloselliflorum Nägeli et Peter (2n = 45), H. pilosellinum F. W. Schultz (2n = 36, 45), H. piloselloides Vill. (2n = 27, 36, ~ 4x, 45, ~ 5x), H. pistoriense Nägeli et Peter (2n = 27), H. rothianum Wallr. (2n ~ 3x), H. schultesii F. W. Schultz (2n = 36, 45, ~ 5x), H. zizianum Tausch (2n = 27, 36, 54), and one hybrid, H. onegense × H. pilosella (2n = 36). Besides chromosome counts in root-tip meristems, flow cytometry was used to determine the DNA ploidy level in 83 samples of 9 species. The presence of a long marker chromosome was confirmed in tetraploid H. caespitosum and H. iseranum, in pentaploid H. glomeratum, and in both tetraploid and pentaploid H. floribundum. The documented mode of reproduction is sexual (H. densiflorum, H. echioides, H. piloselloides) and apomictic (H. brachiatum, H. floribundum, H. pilosellinum, H. piloselloides, H. rothianum, H. zizianum). Hieracium bifurcum and H. pistoriense are sterile. The chromosome number and/or mode of reproduction of H. bifurcum (almost sterile pentaploid), H. pilosellinum (apomictic pentaploid), H. piloselloides (apomictic triploid), H. pistoriense (sterile triploid), H. rothianum (apomictic triploid) and H. zizianum (apomictic triploid) are presented here for the first time. The sexual reproduction recorded in the pentaploid H. echioides is the second recorded case of this mode of reproduction in a pentaploid cytotype of Hieracium subgenus Pilosella. A previously unknown occurrence of H. pistoriense (H. macranthum – H. bauhini) in Slovakia is reported.
The agamosporous and taxonomically critical Dryopteris affinis group was investigated as part of a cytogeographic and morphometric study of ferns in Central Europe. Material from 27 localities in the Czech Republic, Slovakia, Poland and Austria was sampled and evaluated using both morphometric multivariate and karyological analyses. Chromosome counts and flow cytometric analyses revealed the existence of two distinct triploid taxa (2n = 123) of differing genome size, which correspond to D. borreri and D. cambrensis, and of a rare pentaploid hybrid (2n = 205) D. ×critica (D. borreri × D. filix-mas). Morphometric analyses confirmed a clear separation between both triploid taxa. New quantitative characters were selected based on a discriminant analyses, and a key for the identification of the species is presented.
A detailed cytogeographic and morphometric study of the Asplenium trichomanes group in the Czech Republic is presented. We detected diploid (2n = 72), tetraploid (2n = 144) and hybrid triploid plants (2n = 108). Based on the morphometric study, four intraspecific taxa are recognized. These taxa correspond to the four subspecies of A. trichomanes (A. t.subsp. trichomanes, <I.A. t. subsp. quadrivalens, A. t. subsp. pachyrachis and A. t. subsp. hastatum) distinguished in the floras of western, southern and northern Europe. Triploid plants were determined as A. t. nothosubsp. lusaticum (A. t. subsp. trichomanes × A. t. subsp. quadrivalens). The individual morphological characters used for determining subspecies are evaluated and a determination key presented.
Populations of Pilosella (Hieracium subgenus Pilosella) at ruderal localities were investigated in an urban area (Prague City) with respect to their distribution, variation in DNA ploidy level/chromosome number and mode of reproduction. The following species, hybridogenous species or hybrids (with ploidy level/chromosome number and mode of reproduction) were found: P. aurantiaca, P. caespitosa (4x, 5x), P. cymosa subsp. vaillantii (5x), P. officinarum (2n = 36, sexual; 2n = 54, sexual; 2n = 63), P. piloselloides subsp. bauhinii (2n = 45, 54; both apomictic), P. piloselloides subsp. praealta (5x; apomictic), P. brachiata (4x; sterile), P. densiflora, P. flagellaris, P. floribunda, P. erythrochrista, P. glomerata (5x; apomictic), P. leptophyton (5x; apomictic), P. rothiana (4x, apomictic), P. setigera, P. visianii (4x; apomictic), P. ziziana (4x, apomictic) and the previously undescribed hybridogenous type P. piloselloides × P. setigera (5x, apomictic). Pilosella visianii is reported from the Czech Republic for the first time. New habitats resulting from highway construction are suitable for Pilosella species. Many previously rare types, such as P. rothiana, can colonize these habitats and spread, not only locally, but also throughout the whole country.
As a result of inconsistencies in morphological characters, Cerastium pumilum and C. glutinosum have been misunderstood or confused in many European floras since the 1960s. In the second volume of the Flora Nordica, a revised treatment of C. pumilum s.l. is provided and this concept is tested here for eastern Central European populations. The cytometric and morphological part of the study is based on living plants from 85 populations in the Czech Republic, Slovakia, Poland, Austria and Hungary. Flow cytometric analyses of the samples revealed two groups differing in ploidy level and corresponding to two cytotypes (a known octoploid, 2n ≈ 72, for C. glutinosum and yet unknown dodecaploid, 2n ≈ 108, for C. pumilum). Eleven morphological characters were scored or measured in plants of known ploidy level and the data set analysed using multivariate statistics (principal component analysis and canonical discriminant analysis); the two morphologically well-separated groups were identical with the two cytotype groups detected by flow cytometry. Based on these results, we suggest treating the detected cyto-morphotypes as the species C. pumilum and C. glutinosum. Our analysis further revealed that the traditionally used characters (glabrous vs. hairy adaxial surface and presence vs. absence of a scarious margin to the tip of the lowermost bracts) are not taxonomically informative. The characters best differentiating the species include indument on the lowermost vernal internodium, length of mature stylodia, length of glandular hairs on sepals and maximum diameter of mature seed. A key for identification of both species is also provided. A revision of almost 1600 specimens deposited in 16 Central European herbaria revealed that the species show different distribution patterns in Central Europe and partial habitat segregation. Specimens from the Czech Republic previously assigned to C. litigiosum were identified as C. pumilum; consequently, C. litigiosum must be removed from the Czech flora.