Asteraceae research projects
Phylogeny of Senecio sect. Jacobaea (Asteraceae)
P.B. Pelser, Dr. B. Gravendeel and Dr. R. van der Meijden - NHN Leiden
The genus Senecio
(Senecioneae; Asteraceae) is listed amongst the largest genera of flowering plants,
comprising between 1000 and 3000 species and shows a remarkable amount of morphological
variation, both between and within species. These two aspects have greatly hampered
attempts to reconstruct the evolutionary history of Senecio.
A phylogenetic study is currently carried out to find the closest relatives of Senecio jacobaea. This species is notorious because of its poisonous Pyrolizidine Alkaloids (PA’s). These
secondary metabolites are used as defence mechanism against herbivores. Information about
the evolutionary history of the S. jacobaea
group will contribute to a better understanding of the evolution of the different types of
PA's found in S. jacobaea and its relatives.
We are using trnT-trnL, matK and ITS sequence
data to study the phylogenetic relationships within the S. jacobaea group. Interesting aspects are the
occurrence of hybridization between S. jacobaea
and close relatives, and taxonomic problems due to the large morphological variation in
this group. In addition, morphological characters will be studied to find morphological
synapomorphies for the S. jacobaea group and to
asses their value for phylogeny reconstruction in Senecio.
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