The science officer assigned to Deep Space Nine was a Trill, a species that embraced symbiosis with another life form.
This interesting case of symbiosis is equalled by yet another case.
Each species of green plant may form a mycorhiza with two or three different Fungi, and a single species of Fungus may enter into symbiosis with several green plants.
This dualism, where the one constituent (alga) furnishes carbohydrates, and the other (fungus) ensures a supply of mineral matters, shade and moisture, has been termed symbiosis.
Symbiosis: Marshall Ward, " Symbiosis," Ann.
The work of numerous observers has shown that the free nitrogen of the atmosphere is brought into combination in the soil in the nodules filled with bacteria on the roots of Leguminosae, and since these nodules are the morphological expression of a symbiosis between the higher plant and the bacteria, there is evidently here a case similar to the last.