Sorbus omissa is described as a new hybridogenous triploid (2n = 3x = 51) species belonging to the Sorbus latifolia group. This species is considered to be of hybrid origin, with S. danubialis and S. torminalis being its putative parental species. It is a stenoendemic whitebeam occurring in central Bohemia (Czech Republic) in the vicinity of the towns of Roztoky and Libčice nad Vltavou (Praha-západ district) in the valley of the lower Vltava river, where it grows primarily in oak forests (Viscario-Quercetum). The only two known populations contain approximately 150 individuals. This species differs from other similar Czech species of the S. latifolia group in having broadly elliptical to rhomboidal leaves with very shallowly lobed laminas, predominantly with 9–11 lateral leaf veins on each side, and is orange to orange-red fruit at maturity. Observation, morphological comparison and karyological (chromosome counts, DAPI flow cytometry) methods were used to identify this new species. A character-comparison table and a determination key including all taxa of the S. latifolia agg. endemic in the Czech Republic are provided. An illustration, a photograph and a distribution map of this new species are also presented.
Two new apomictic triploid (2n = 3x = 51) species from the Sorbus latifolia group, S. portae-bohemicae M. Lepší, P. Lepší, P. Vít et K. Boublík and S. albensis M. Lepší, K. Boublík, P. Lepší et P. Vít, putative hybridogenous species originated from a cross between S. danubialis and S. torminalis, are distinguished and described based on a taxonomic and chorological revision of Sorbus bohemica (a hybridogenous triploid species from the same parental combination). A number of contemporary biosystematic techniques, including molecular (nuclear microsatellite markers), karyological (chromosome counts, DAPI flow cytometry) and multivariate and geometric morphometrics were used to assess the variation of the species and justify their independent taxonomic status. All three species occur sympatrically in the České středohoří Mts (NW Bohemia). Sorbus bohemica is recorded from 31 localities, based on a revision of herbarium vouchers and field research. Recent field studies failed to verify five of these localities. Sorbus portae-bohemicae is a stenoendemic in the Porta bohemica gorge (situated ca 7 km WNW of Litoměřice) where it grows in open oak forests (Luzulo-Quercetum and transition vegetation type to Melampyro nemorosi-Carpinetum) on ENE-facing slopes and rocks. The only known population of S. portae-bohemicae consists of 14 adult individuals. Sorbus albensis occurs at 12 localities W to NW of Litoměřice. The total number of individuals is estimated at 600. Most are in acidophilous oak forests (Luzulo-Quercetum and its mesic derivatives), scree forests (Aceri-Carpinetum) or shrubby slopes (Pruno-Ligustretum, Antherico-Coryletum). Populations of the new taxa show little genetic variation and are phenotypically homogenous and well separated from other Bohemian hybridogenous Sorbus species. A distribution map of the three species is provided. Photographs of the type specimens and in situ fructiferous individuals of the new species are presented.
A taxonomic study of the Pilosella alpicola group growing in the Carpathians revealed the presence of two morphologically distinguishable taxa: P. ullepitschii (Błocki) Szeląg and P. rhodopea (Griseb.) Szeląg. While P. ullepitschii is endemic to the Carpathians, P. rhodopea is a Balkan subendemic with two isolated localities in the Southern Carpathians (Mt Cozia and Mt Zmeuretu). The core area of distribution of P. ullepitchii is the natural subalpine and alpine meadows of the Western Carpathians (the Vysoké and Západné Tatry Mts in Slovakia and Poland). In addition, only three isolated localities are known from the Nemira Mts (Romanian Eastern Carpathians) and one from the Bucegi Mts (Romanian Southern Carpathians). Interestingly, the Romanian populations occur in man-made habitats (secondary pastures). Karyological and flow cytometric analyses of 305 plants from 13 populations of P. ullepitschii revealed only diploid plants (2n = 2x = 18). One Carpathian population of P. rhodopea from Mt Cozia is also diploid. This is the first report of diploidy in this species. However, the populations from the main part of the distribution of this taxon in the Balkan mountains include other cytotypes. Detailed morphological descriptions and distributions for both taxa are given.
Sorbus eximia Kovanda, a hybridogenous species that originated from the parental combination S. torminalis and S. aria s.l., is thought to be an apomictic species, which includes diploid and tetraploid individuals. The present study confirmed the existence of only triploid individuals. A new tentatively apomictic triploid (2n = 3x = 51) species from the S. latifolia group: S. barrandienica P. Vít, M. Lepší et P. Lepší is described based on a revision of S. eximia. This species is assumed to have originated from a cross between S. danubialis or S. aria s.l. and S. torminalis. A wide palette of biosystematic techniques, including molecular (nuclear microsatellite markers) and karyological analyses (chromosome counts, DAPI flow cytometry) as well as multivariate morphometric and elliptic Fourier analyses, were used to assess the variation in this species and justify its independent taxonomic status. Allopatric occurrences of both species were recorded east of the town of Beroun in the Český kras, central Bohemia (Bohemian Karst). A distribution map of the two species is provided. Sorbus eximia occurs at four localities (the total number of adults and juveniles is 100 and 200, respectively) in basiphilous thermophilous oak forests (Quercion pubescenti-petraeae), mesic oak forests (Melampyro nemorosi-Carpinetum), woody margins of dry grasslands (Festucion valesiacae) and pine plantations. Sorbus barrandienica has so far been recorded at 10 localities (ca 50 adults). Recent field studies failed to verify two of these localities. It is mainly found growing on the summits of hills, usually in thermophilous open forests (Primulo veris-Carpinetum, Melampyro nemorosi-Carpinetum, Quercion pubescenti-petraeae) and woody margins of dry grassland. Its populations exhibit minimal genetic variation and are phenotypically homogeneous and well separated from other Bohemian hybridogenous Sorbus species. The epitype of S. eximia is designated here, and a photograph of the specimen is included. Photographs of the type specimens and in situ individuals, and line drawings of both species are presented.