Botany — The Yale Herbarium

Current Research in the Division of Botany

Phylogeography of the Campanulaceae,
Dipsacaceae and Valerianaceae in the Cretan Area

This project is sponsored by the Stavros S. Niarchos Foundation and promotes a collaboration between the Peabody Museum of Natural History, Yale University, and the Natural History Museum of Crete.

The evolutionary history of the Cretan Campanulaceae, Dipsaceae and Valerianaceae has not yet been studied. Given the degree of endemism within these groups, the proposed research provides an ideal starting point to formulate hypotheses on the historical biogeography of the Cretan area, and assess whether these small islands have acted more as refugia rather than evolutionary laboratories.

The Dipsacaceae is a family comprising 5 genera (Cephalaria, Lomelosia, Knautia, Pterocephalus and Sixalis) and 11 species. These plants grow on calcareous rocks, cliffs, and abandoned terraces often on rocky phrygana, and their elevational distribution ranges from 0 to1,800 meters (0 to 5,906 feet). Lomelosia represents the largest genus with 6 species, 3 of which are endemics.

The Valerianaceae includes 4 genera (Centranthus, Fedia, Valeriana and Valerianella) and 13 species. Valeriana asarifolia and Centranthus sieberi represent the endemics in this group. These plants are also found on calcareous substrates, cliffs, rocky places, gorges and coastal phrygana, and the elevation ranges from 0 to 2,300 meters (0 to 7,546 feet).

The family Campanulaceae comprises 5 genera (Asyneuma, Campanula, Legousia, Petromarula and Solenopsis) and 22 species, 17 of which are endemic to this area. These plants grow in calcareous rock crevices, steep slopes, cliffs and old walls, and their elevational distribution ranges from 0 to 2,300 meters (0 to 7,546 feet). In some cases, for example, Campanula jacquinii, populations are confined to the major mountain systems of west, central and eastern Crete, whose peaks were once isolated islands. Patterns of differentiation linked to geographical distribution can be explained by fragmentation of the areas and isolation followed by adaptation to the particular environmental conditions. Alternatively, it could consist of a random shift of gene frequencies, especially for neutral, nonadaptive alleles.

Interesting questions can be formulated regarding the occurrence and distribution of these taxa in the area. When did colonization of the Campanulaceae, Dipsacaceae and Valerianaceae occur? Did clades colonize Crete in a single event followed by adaptive radiation, or did colonization and evolution occur through multiple, independent events? Endemism is not necessarily to be equated to evolution. Some of the present endemics could be remnants of the old continental flora that have not evolved since the Upper Miocene. Therefore, it is possible that elements in the Campanulaceae, Dipsacaceae and Valerianaceae could represent palaeorelicts of the continent having differentiated before the splitting up of the Aegean landmass, which have since been conserved in restricted habitats. As an example, preliminary phylogenetic results indicates that the monotypic endemic genus Petromarula is basal in the Campanulaceae (Jansen, pers. comm.) suggesting that Petromarula is indeed a relict and might have survived extinction in Crete.

Principal Investigator Nico Cellinese
Co-Principal Investigator Michael Donoghue
Co-Principal Investigator Reed Beaman

Students Erika Edwards, Sang-Tae Kim
Collaborator Robert Jansen (University of Texas, Austin)

Partners in Crete

Kiriakos Kotzabasis Principal Investigator,
University of Crete and Natural History Museum of Crete

Manolis Avramakis Co-Principal Investigator
Natural History Museum of Crete

Eleni Navakoudis Student
Nikos Ioannidis Student

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