Orchids and Fungi

Many flowers live in symbiosis with fungi: the fungus receives nutrients from the plant, but the plant also benefits from the relationship.

For example, the seeds of orchids are unable to germinate unless they are first invaded by fungi. This invasion is not an 'attack', however, but a co-operative relationship in which the young orchids are not damaged.

The Birds Nest Orchid, illustrated here, does not contain chlorophyll. As a result, the orchid is unable to synthesise its food using sunlight in the way that most plants do. Instead, therefore, this strange plant not only needs fungi to invade its seeds before they can germinate but it also retains the fungus throughout its life.

The many species of Broomrapes - sombre looking parasitic plants that live off the roots of particular shrubs and wild flowers - are sometimes mistaken for the Birds Nest Orchid. Broomrapes also lack chlorophyll and so are incapable of photosynthesising the food they need.