Mycorrhizal evolution

Two recent studies have cast new light on the evolutionary history of mycor rhizae. New fossil evidence has pushed the date for the appearance of arbus cular mycorrhizae back to 460 million years ago, predating vascular plants. A phylogenetic tree for the Basidiomycota shows that these fungi have gain ed (and lost) the ectomycorrhizal condition repeatedly during their history . These studies help highlight the paleoecological importance of mycorrhiza e and add to our understanding of the evolution of mutualisms.