The origin of land plants: a matter of mycotrophism.

It is hypothesized that terrestrial plants are the product of an ancient and continuing symbiosis of a semi-aquatic ancestral green alga and an aquatic fungus-an oomycete. The Siluro-Devonian "explosive" colonization of land, and indeed the very evolution of plants, was possible only through such mutualistic partnerships-partnerships that were equipped to cope with the problems of desiccation and starvation associated with terrestrial existence.