Phylogenetic relationships among species ofHypochaeris(Asteraceae, Cichorieae) based on ITS, plastidtrnLintron,trnL‐Fspacer, andmatKsequences

Abstract

Nuclear internal transcribed spacer (ITS) regions and chloroplast trnL intron and trnL/trnF spacer and matK sequences were used from 86 accessions to assess relationships among 31 European and South American species of Hypochaeris plus 18 representatives of related genera of tribe Cichorieae. The ITS tree shows high resolution compared to that of the maternally inherited trnL intron, trnL/F spacer, and matK sequences. The ITS and the combined tree reveal clades that agree well with sections of the genus established previously on morphological and cytological grounds, except for H. robertia, which groups with Leontodon helveticus and L. autumnalis. Monophyly of species of Hypochaeris from South America is strongly supported by both ITS and the joint matrix of ITS, trnL, and matK data. European species lie basal to South American taxa, which suggests that species in South America evolved from a single introduction from European progenitors and not from H. robertia as suggested previously. Low levels of sequence divergence among South American taxa suggest a pattern of rapid speciation, in contrast to much greater divergence among European representatives. Different species of Leontodon form two different clades that are also supported by chromosome numbers and morphology. Both nuclear and chloroplast markers suggest that Helminthotheca, Leontodon, and Picris are closely related to each other as well as to Hypochaeris.

Chromosomal organization and phylogenetic relationships in Hypochaeris species (Asteraceae) from Brazil

“…Cluster analysis associated the species under study into two major groups, comprising the South American and the European species, with a mean genetic similarity of only 34.7% (Table 3) and a 100% bootstrap support. These results are in agreement with the hypothesis of a monophyletic origin for the South American Hypochaeris species (Samuel et al 1999;2003).…”

“…Recently, molecular systematic analysis has been used for phylogenetic studies within the genus Hypochaeris Samuel et al, 1999). Sequence analyses of nuclear ITS regions and chloroplast trnL-F intron, trnL/trnF spacer and matK sequences, carried out to assess phylogenetic relationships among European and South American species of Hypochaeris, revealed that, except for H. Robertia, the clades formed by the ITS and the combined trees agree with sections previously stablished for the genus on the basis of morphological and cytological studies Samuel et al, 1999Samuel et al, , 2003. These observations provided evidence for monophyly of the South American species, which would have evolved from a single introduction of European progenitors rather than from H. robertia, as previously suggested (Barghi et al, 1989).…”

“…Taxonomy and phylogenetic relationships of the genus Hypochaeris have been discussed based on a sequencing data set of ITS regions (Cerbah et al, 1998b;Samuel et al, 1999;2003) and plastidial intergenic TrnL and mat-K sequences (Samuel et al, 1999;2003). These authors suggested that South American Hypochaeris species constitute a monophyletic group that was probably derived from a single progenitor introduced from Europe.…”

Trichomes in the tribe Lactuceae (Asteraceae) — taxonomic implications

“…Even not in the case of such morphologicaly compact and unambigously distinguishable structures as the F3 type, which presence suggests strong similarity between the genera Picris, Leontodon, Hyoseris and Hedypnois. This relationship is supported by other studies (Stebbins 1953;Jeffrey 1966;Baagøe 1980;Blackmore 1981;Bremer 1994;Blackmore & Persson 1996;Samuel et al 2003) as well. However due to their co-occurrence with several (and widespread) types from which only the F3 is shared by all four genera, it is not reflected in the resulting tree.…”

Estudios Citogeneticos en Poblaciones De Hypochaeris Apargioides Hook. Et Arn. (Asteraceae, Lactuceae) De Chile

“…El género Hypochaeris L. (Asteraceae) comprende alrededor de 60 especies en el mundo, de las cuales 50 se encuentran confinadas a América del Sur, 10 especies a Europa y 3 especies a Asia (Siljak-Yakovlev et al 1994;Bortiri 1999;Baeza et al 2000;Samuel et al 2003;Weiss et al 2003a, b;Stuessy et al 2004). Es un género que muestra una variabilidad morfológica muy grande, especialmente en los caracteres vegetativos, encontrándose desde especies muy pequeñas (H. acaulis (J.Remy) Britton) a otras muy grandes (H. apargioides Hook.…”