Evolution and systematics of European spurges (Euphorbia)

Euphorbia (Euphorbiaceae) is with over 2150 species one of the largest genera of flowering plants. In Europe, it is represented by more than 100 species with highest diversity in the Mediterranean area; the majority of taxa belong to the species-rich subgenus Esula. The few available phylogenetic studies of Euphorbia showed that most members of subg. Esula, along with some additional taxa, form a monophyletic clade but the phylogenetic relationships within the clade remain poorly understood.
We explore phylogenetic relationships within the subgenus Esula, using nuclear and plastid DNA sequences, sampling predominately European taxa. We attempt to estimate the temporal scale of diversification of our study group and trace the evolution of morphological characters, which were used for classification purposes.

Our studies are imbedded within the global biodiversity inventory project of spurges, "EuphORBia  PBI”, where we also take part.

We focus on evolutionary patterns within various groups within Euphorbia

  1. Euphorbia sojakiiEvolution of the European members of the Euphorbia villosa group We explore how the morphological diversity of several European endemics (E. austriaca, E. sojakii, E. carpatica) corresponds to their phylogenetic relationships, and evaluate their distinctiveness from the widespread E. villosa. The work is performed in cooperation with Maja Graniszewska, from the Warsaw University Herbarium (WA).


  2. Euphorbia fontquerianaEvolutionary patterns and diversification of the Mediterranean members of the section  Myrsinites
    Euphorbia myrsinites
    and E. rigida are widespread Mediterranean taxa. We explore their relationships with stenoendemic taxa from some Mediterranean islands: E. fontqueriana from Mallorca, E. corsica from Corsica, E. rechingeri from Crete and E. veneris from Cyprus. Is their diversification connected with geological history of these Mediterranean islands (vicariance) or result of much later long-distance dispersal?

  3. Euphorbia pithyusaThe Euphorbia saxatilis-triflora-kerneri-herzegovina complex is disjunctly distributed in the northeastern and southeastern Alps and the Dinaric Mountains. Euphorbia saxatilis is endemic to the Northeastern Calcareous Alps of Austria, whereas the three other species grow in the Southeastern Calcareous Alps and the Dinaric mountains: E. triflora on Caven in Slovenia and on Velebit and Gorski Kotar in Croatia, E. kerneri on the southern outskirts of the Carnic Alps and the southwestern outskirts of the Julian Alps, and E. hercegovina in the Dinaric Mountains from Bosnia and Herzegovina to Montenegro. Do they really form a monophyletic group? Is E. barrelieri their closest relative, as traditionally assumed, or were other taxa from the section Conicocarpae also involved in their evolution?

We are also involved in the "Flora of Istria" project, providing a revision of Euphorbiaceae for Istria and the Kvarner bay(NW Croatia, Slovenia, Italy).

Funding
Wissenschaftlich-Technische Zusammenarbeit Österreich-Slowenien (ÖAD , Austrian Exchange Service)[Link]

Personnel involved
Božo Frajman
Peter Schönswetter

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