Identity and relationships of Sempervivum tectorum (Crassulaceae) in the Rhine Gorge area

Abstract

Sempervivum tectorum (Crassulaceae), an orophyte widespread in the European high mountains, also grows in rocky habitats of the Rhine Gorge area (Upper Middle Rhine, Mosel and Ahr river valleys). On the background of its long history of cultivation, it is unclear whether S. tectorum is native or naturalized in the Rhine Gorge area. Using 52 accessions of S. tectorum from across its geographical range (except SE Europe) as well as 15 samples of S. calcareum and S. marmoreum in our final sample, we conducted a genotyping-by-sequencing analysis. The genetic data were used for the identification of genetic groups and for the reconstruction of phylogenetic relationships. We found that the material from the Rhine Gorge area forms a homogeneous genetic group that is clearly distinct from populations from the Massif Central, Alps and Pyrenees. The Rhine Gorge material appears to be most closely related to material from the Massif Central. We hypothesize that the disjunct distribution of the Rhine Gorge/Massif Central clade is best interpreted as the remnant of a formerly wider distribution area obtained in a Quaternary glacial. The possibility of recognizing Rhine Gorge material taxonomically is discussed and rejected for morphological and nomenclatural reasons.

Hybridization, ecogeographical displacement and the emergence of new lineages – A genotyping‐by‐sequencing and ecological niche and species distribution modelling study of Sempervivum tectorum L. (Houseleek)

“…(2003), MC is essentially identified as a separate lineage with a very small amount of admixture with RG, and PYR showing a small amount of admixture with MC. In an earlier structure analysis including samples from the Alps, Fabritzek and Kadereit (2018) found a somewhat larger proportion of RG than of PYR in MC at K = 4, the most likely K using Evanno et al (2005), and identified MC as a separate lineage with only very small amounts of admixture from other clusters at K = 7, the most likely K using Falush et al. (2003).…”

“…Considering the extant geographical distribution of the three lineages (RG, MC, PYR) in western Europe (Figure 1) and the fact that Apennine populations of S. tectorum were never found to be closest relative to any of them by Fabritzek and Kadereit (2018; see Figure S1), we assume that an origin of the MC lineage in Iberia is more likely than its origin in the southern Apennine or on Sicily. Also, close relationships between populations from the Iberian Peninsula, the Massif Central and various parts of Central Europe have been reported for several plant and animal taxa (Hewitt, 2000; Taberlet et al., 1998), and Iberian‐Pyrenean‐Massif Central (Zetzsche, 2004), Pyrenean‐Massif Central (Valtueña et al., 2012) and Massif Central‐Central European (Huck et al., 2009) relationships have been reported for other plant species.…”

“…However, as pointed out above, identification of the Sierra de Gredos or the Galician‐Portuguese Mountains as possible areas of origin of the MC lineage is far from certain. (d) Ecogeographical displacement of the hybrid lineage, possibly catalysed by past climatic change, resulted in reproductive isolation from the parental lineages and thus initiated the independent evolution of MC, which had been identified as a distinct phylogenetic lineage by Fabritzek and Kadereit (2018) and as a distinct genetic cluster at some values of K (refer above).…”

“…In the western part of its range, S. tectorum is highly disjunctly distributed in the Rhine Gorge area in Germany (comprising the Upper Middle Rhine, Mosel and Ahr river valleys), the Massif Central in France and the Pyrenees in France and Spain (Figure 1). In a recent phylogenetic study of S. tectorum in these areas using genotyping‐by‐sequencing (GBS) data by Fabritzek and Kadereit (2018), which aimed at demonstrating that the Rhine Gorge material of the species represents an independent phylogenetic lineage native to that area, it was found that populations from the Massif Central might be composed of the gene pools of Rhine Gorge area and Pyrenean populations. Although currently no generally accepted intraspecific classification of S. tectorum is available (Parnell & Favarger, 1993), material from the Rhine Gorge area, the Massif Central and the Pyrenees has been recognized at specific (and also other) rank in the past: S .…”

The Influence of Extracts from Common Houseleek (Sempervivum tectorum) on the Metabolic Activity of Human Melanoma Cells WM-266-4

“…It is easily recognized by its distinctive fleshy and pointed leaves, which form a rosette and prevent water from evaporating [12]. It is not sensitive to cold or drought and can grow on sandy soils even in the worst climatic conditions [13]. S. tectorum is widely known as a folk medicine, and its juice is still used today for healing wounds, burns, and insect bites as a refrigerant and astringent [14].…”