A combined study of morphology, stem anatomy and DNA sequencing data (nuclear ribosomal ITS region and rpl32-trnL and rps12-rpl20 intergenic spacers of chloroplast DNA) was used to identify a putative Potamogeton hybrid from a river in NE Poland. Based on the morphological and anatomical characters the plants were tentatively identified as P. ×subobtusus Hagstr., a hybrid between P. alpinus Balb. and P. nodosus Poir. This identification was independently confirmed by the presence in hybrid individuals of an additive ITS sequence pattern from these two parental species. In all plants peaks corresponding to nucleotide states of both parents were clearly distinguishable, however the variants from P. nodosus dominated over those from P. alpinus. P. nodosus was also identified as the maternal parent of the hybrid based on cpDNA data and dominated the expression of morphological features in hybrid individuals. A detailed morphological description of P. × subobtusus and the typification of the name are provided. As P. nodosus rarely hybridizes with other species, existence of other hybrids, as well as possible difficulties in recognizing these taxa are also discussed.
Plant names based on the original material from a restricted region are scientifically important for the study of local biodiversity. Names typified with or entirely based on the original material from the Czech Republic are studied in the present paper; the names are confined to cases of generally accepted names published and taxa described in the period 1753–1820. Some names with original material coming from a border region (mostly near the Polish border) are included, too. Brief notes and references are given to introduce the authors of names and the history of their herbarium collections. New data are given on publications and herbaria of F.W. Schmidt, T. Haenke and J. E. Pohl, including examples of their handwritings; the other authors being C. Linnaeus (and J. Burser), J. Zauschner, K. L.Willdenow, J. C. Mikan, K. Sternberg, H. A. Schrader, L. Trattinick, K. B. Presl, J. S. Presl, P. M. Opiz, I. F. Tausch and H. G. L. Reichenbach. Nomenclatural and taxonomic notes are given on Aconitum plicatum, Allium senescens subsp. montanum, Gagea bohemica, Plantago uliginosa, Spergularia salina, Valeriana officinalis, V. exaltata, V. sambucifolia and Veronica triloba. A number of names are typified (lecto-, neo- , epitypes): Allium montanum, Athyrium distentifolium, Erysimum arcuatum (= Barbarea vulgaris subsp. arcuata), Schmidtia (= Coleanthus) subtilis, Epilobium nutans, Ornithogalum bohemicum (= Gagea bohemica), Hieracium sudeticum, Myosotis sparsiflora, Cynoglossum (= Omphalodes) scorpioides, Pedicularis sudetica, Phyteuma nigrum, Plantago uliginosa (with an identification key), Poa laxa, Soldanella montana, Symphytum bohemicum, Thlaspi caerulescens, Valeriana exaltata (with notes on the typification of V. officinalis), V. sambucifolia, Veronica triloba (with a note on the status of names in Čelakovský‘s works), Viola sudetica and V. saxatilis. The other names included in the list are Avenula planiculmis, Cardamine amara subsp. opicii, Eriophorum vaginatum, Hieracium rupestre (= H. schmidtii), Luzula sudetica, Mentha longifolia, Potentilla lindackeri, Rosa elliptica, Salix silesiaca, Stipa capillata and Viola rupestris. A few cases of names excluded from the list are also analysed: Achillea millefolium subsp. sudetica, Alchemilla fissa, Carex bohemica, Dactylorhiza longebracteata, Gagea pusilla, Geranium bohemicum, Matricaria recutita, Veronica dentata, Spergularia salina (correct name: S. marina), Gentianella obtusifolia, Myosotis alpestris and Mentha rotundifolia. For most cases, conservation status and situation at the original localities (in many cases in protected areas) are discussed.
A revision of the diversity and distribution of Potamogeton hybrids in the Czech Republic is presented. Thorough examination of herbarium material and recent extensive field studies revealed the present and/or past occurrence of eight Potamogeton hybrids in the Czech Republic. In addition tomorphological characters, stem anatomy and/or molecular analysis were used to identify some of the hybrids. All the hybrids detected are between broad-leaved species of the genus, suggesting that hybrids between linear-leaved species may be overlooked because of the overall morphological similarity of taxa within this group. Four of the hybrids identified, P. ×nitens, P. ×olivaceus, P. ×sparganiifolius and P. ×undulatus, are recorded for the first time from the Czech Republic. Four of the hybrids are now extinct in the Czech Republic and the extant hybrids are rare. The occurrence of P. ×lintonii was not confirmed; the previous record was based on extreme forms of P. gramineus. The name P. ×concinnitus, proposed for a putative hybrid combination “P. pusillus × P. crispus”, was lectotypified and reduced to a synonym of P. crispus. Although the absolute number of finds of specimens of Potamogeton hybrids per decade is increasing, this is not a result of more frequent hybridization but of an increase in recording activity. Most records for recent decades are associated with targeted research by a few experts. The typical habitat of Potamogeton hybrids in the Czech Republic are ponds that were previously drained in summer and allowed to dry out. Many historical localities disappeared when the traditional fishpond management was largely abandoned and fish farming become more intensive. In the 19th century in particular some hybrids were recorded also in rivers but these occurrences generally disappeared after the extensive channelling of rivers at the beginning of the 20th century. Many hybrids occur at the same localities as their parents but it is documented that hybrids can persist vegetatively in the absence of the parental species, presumably as relics of the previous presence of the parent plants. Although almost all Potamogeton hybrids are consistently sterile, a cultivation experiment showed that P. ×angustifolius set seeds that were fertile and successfully produced adult plants.
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).