Phylogenetic relationships among and within the subsections of the genus Viola are still far from resolved. We present the first organismal phylogeny of predominantly western European species of subsection Rostratae based on the plastid trnS-trnG intron and intergenic spacer and the nuclear low-copy gene chalcone synthase (CHS) sequences. CHS is a key enzyme in the synthesis of flavonoids, which are important for flower pigmentation. Genes encoding for CHS are members of a multigene family. In Viola, 3 different CHS copies are present. CHS gene lineages obtained confirmed earlier hypotheses about reticulate relationships between species of Viola subsection Rostratae based on karyotype data. Comparison of the CHS gene lineage tree and the plastid species phylogeny of Viola reconstructed in this study indicates that the different CHS copies present in Viola are the products of both recent and more ancient duplications.
Jacobaea vulgaris (Asteraceae) is a species of Eurasian origin that has become a serious non-indigenous weed in Australia, New Zealand, and North America. We used neutral molecular markers to (1) test for genetic bottlenecks in invasive populations and (2) to investigate invasion pathways. It is for the first time that molecular markers were used to unravel the process of introduction in this species. An assignment test showed that European populations from Ireland, the Netherlands and the United Kingdom most resembled the invasive populations.
The taxonomic and nomenclatural histories of Viola elatior Fr. (1828), V. pumila Chaix (1785) and V. stagnina Kit. ex Schult. (1814) in central and western Europe are discussed. The names V. stagnina and V. elatior are lectotypified with specimens corresponding to the current use of these names. The neglected lectotypification in 1988 of V. montana L. (1753) with a specimen referable to V. elatior is briefly reviewed. The name V. persicifolia Schreb. (1771), used in some floras instead of V. stagnina, is analysed in detail, and we conclude that this name should be interpreted as referring also to V. elatior. In addition the types of V. hornemanniana Schult. (1819) and V. stipulacea Hartm. (1820) are conspecific with V. elatior. The use of V. persicifolia and V. montana, representing earlier legitimate names for the species widely known as V. elatior, has been notoriously confused for two centuries, and we herein recommend these two names for rejection in order to assure nomenclatural clarity and stability. For similar reasons, we recommend conservation of V. elatior against V. hornemanniana and V. stipulacea.
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