We present a molecular phylogeny including most species of the genus Medicago L. This phylogeny is based on the sequences of ITSl and ITS2 (nuclear ribosomal internal transcribed spacers) and ETS (external transcribed spacer) (3), and includes 56 species. Based on the strict consensus of the 48 most parsimonious trees, an evolution of the genus is proposed, and taxonomic implications are discussed. Major incongruences were found between phylogenetic relationships and morphological classification of the genus (4). Most of the sub-genera revealed to be paraphyletic. However, the reconstruction confirms the assignment of the medicagoid species from the genus Trigonella to Medicago (1,2). Life history (5), morphological and cytological traits were mapped onto the phylogeny and their evolution studied. References (1) Lesins K.A. and Lesins I. (1979) Genus Medicago (Leguminosae). A taxogenetic study. Dr. W. Junk, The Hague. (2) Small E. and Jomphe M. (1988) A synopsis of the genus Medicago (Leguminosae). Can. J. Bot. 67: 3260-3294. (3) Bena G., Jubier M.F., Olivieri I. and Lejeune B. (1998) Ribosomal external and internal transcribed spacers: Combined used in the phylogenetic analysis of Medicago (Leguminosae). J. Mol. Evol . 46: 299-306 (4) Bena G., Prosperi J.M., Lejeune B. and Olivieri I. (1998) Evolution of armual species of the genus Medicago: A molecular phylogenetic approach. Mol. Phyl. Evol . In press (5) Bena G., Lejeune B., Prosperi J.M. and Olivieri I. (1998) Molecular phylogenetic approach for studying life-history evolution: The ambiguous example of the genus Medicago L. Proc. Roy. Soc. London B . In press.



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