A detailed study of Taraxacum sect. Ruderalia for the 8th volume of the Flora of the Czech Republic revealed five new agamospermous species, viz. T. atroviride Štěpánek et Trávníček, T. clarum Kirschner, Štěpánek et Trávníček, T. moldavicum Chán, H. Ollgaard, Štěpánek, Trávníček et Žíla, T. urbicola Kirschner, Štěpánek et Trávníček and T. violaceifrons Trávníček. These species are formally described, thoroughly characterized morphologically and compared with similar taxa. They are known from numerous localities in Central Europe; T. moldavicum, in addition to the Central European distribution, is known to occur in two regions in Denmark. All these species are also documented by photographs of their general habit and important features.
Examples of Taraxacum species (sect. Ruderalia) that have a well-known main distribution area and, a few rather isolated, obviously introduced occurrences, are given. The lack of a long tradition of specific knowledge and collection of Taraxacum sect. Ruderalia specimens have impeded our understanding of the origin of the present distributions. Some views are presented. Taraxacum ancistratum, T. crassum, T. deltoidifrons, T. infuscatum, T. jugiferum, and T. lundense, all belonging to Taraxacum sect. Ruderalia, are described as new species. Three or four of these species were first found as introductions far away from their supposed main distribution area.
A comparative study of material of Sempervivum marmoreum Griseb. from the type locality (Mt Athos, Greece) and the northern part of its distribution revealed a distinct morphotype occurring in an isolated enclave along the Slovak–Hungarian border. As its karyotype differs it is formally described here as a new species – Sempervivum matricum Letz. The name Sempervivum assimile Schott, formerly considered as a possible name for this species is here critically examined. A morphological characterization of the new species, photographs of the plant and a distribution map based on revised herbarium specimens are provided.
Two new species, Taraxacum maricum and Taraxacum cristatum, of the section Erythrosperma from Central Europe are described in this paper. These species are similar to western European taxa, T. maricum to T. proximum, and T. cristatum is morphologically close to T. scanicum. Both new taxa are triploid apomictic microspecies. Specific characteristics, information on distribution and ecology and comparison with similar species are presented. Pictures and distribution maps of the new species are also included.
A new genus, Vindobonella gen. n. (Acerentomidae s. l.), and a new species, Vindobonella leopoldina sp. n., are described from Vienna. The new genus belongs to a group characterized by a reduced labial palp and a non-modified striate band on abdominal segment VIII.