endophyte

As an adjective intracellular

is inside or within a cell.

As a noun endophyte is

any organism that lives inside another plant.

As nouns the difference between entophyte and endophyte

is that entophyte is any plant growing as a parasite within another organism while endophyte is any organism that lives inside another plant.

As nouns the difference between endophyte and epiphyte

is that endophyte is any organism that lives inside another plant while epiphyte is a plant that grows on another, using it for physical support but obtaining no nutrients from it and neither causing damage nor offering benefit; an air plant.