Hallingbäck, Tomas
- SLU Swedish Species Information Centre, Swedish University of Agricultural Sciences
Abstract
The genus Riccia is the most species-rich genus among complex thalloid liverworts in Europe. High intraspecific variability in presumed diagnostic thallus characters leads to problems in species delimitation. We started a morphological and phylogenetic study of 105 specimens assigned to R. bifurca, R. glauca, R. gothica, and an unknown entity morphologically related to these species. Selected characters were statistically analyzed and compared to molecular results obtained by sequencing three nuclear marker regions: the commonly used ITS2 and two single-copy markers, RPB1 and an anonymous locus, both specifically targeted for the first time in bryophytes. These data indicate, that R. bifurca, R. glauca, and R. pusilla (the unknown entity) display distinct linages reflected in spore morphology. Riccia gothica forms a subclade within R. pusilla, thus we interpret the taxon as a subspecies of. R. pusilla. Lectotypification of R. pusilla and R. gothica is carried out. Both subspecies are more widespread in Central Europe than previously assumed, but precise distribution is still unknown. We show that only spore characteristics are useful to distinguish the four taxa, which we present in detail. Similarity in spore morphology does not reflect phylogenetic relationships. Overinterpretation of thallus characteristics could lead to failure in determination of Riccia-species.
Keywords
ITS2; lectotypification; Marchantiales; RPB1; spore morphology; taxonomy
Published in
Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology
2025
Publisher: TAYLOR AND FRANCIS LTD
SLU Authors
UKÄ Subject classification
Botany
Biological Systematics
Publication identifier
- DOI: https://doi.org/10.1080/11263504.2025.2485993
Permanent link to this page (URI)
https://res.slu.se/id/publ/141976