A new Pyrenean hybrid Cirsium (Asteraceae) as revealed by morphological and molecular analyses.
A new nothosubspecies Cirsium ×vivantii
is described after a molecular and morphological characterization of eight
individuals collected in two separate valleys of the French central Pyrenees. Both hypervariable Amplified Fragment Length Polymorphism (AFLP) markers and nuclear rDNA (ITS) and plastid (trnL-F, TRNT-L) DNA sequences were
analysed. The profiles of these hybrid samples were compared to those of 43 individuals belonging to their presumed parental taxa C. carniolicum
ssp. rufescens and C. palustre . A total of 133 AFLP bands were scored from three
primer-pair combinations. All 130 AFLP bands that amplified in the hybrid samples were present in either C. carniolicum ssp. rufescens, C. palustre
or both taxa, supporting the participation of these plant genomes in the
resulting hybrids. Several Additive Polymorphic Sites (APS) detected in the ITS sequences of the hybrid samples also
confirmed their derived origins from ribotypes of the two parental taxa. The lack of exclusive AFLP markers and the nonconcerted evolution of rDNA polymorphisms towards either of the parental ribotypes indicated their recent origin.
Plastid trnT-L sequences were used to identify C. palustre as the maternal parent of six of these hybrid individuals; either parent could have acted as the plastid genome donor for the other two individuals. The morphological
study revealed that all hybrid individuals were morphologically intermediate between their parents showing largely lobed and less spiny basal leaves as in
C. carniolicum ssp. rufescens and decurrent leaf bases and pinkish corollas as
in C. palustre