Resumen de Hypericum dubium Leers�New Data on Taxonomy and Biology
New data on the taxonomy, karyology, reproductive biology and secondary metabolites of Hypericum dubium Leers (=H. maculatum subsp. obtusiusculum (Tourlet) Hayek) are given. The neotypification of the name H. dubium by plants from the locus classicus near the town of Herborn in Germany is presented. Hypericum dubium is characterized by stems with slightly conspicuous subsidiary lines, sepals with a finely denticulate or rarely entire apex, petals with pale and black, linear to striiform laminar glands. Karyological data confirm that the taxon is tetraploid (2n?=?32). Reproduction by facultative apomixis was discovered using a flow cytometric seed screen. In the spectrum of secondary metabolites, flavonoids, naphtodianthrones and phloroglucinol derivatives were found. The previously described taxon H. carpaticum Mártonfi is reclassified here to the level of nothospecies as H. dubium × H. maculatum. For the epitheton balcanicum a new combination Hypericum ×carinthiacum nothosubsp. balcanicum (N. Robson) Mártonfi is proposed. Finally, this paper provides a revised scheme of relationships among taxa of the H. maculatum group.
