Arum type

Arum-type refers to the morphology of fungal hyphae living in, or around plant root cells.

Forms in arbuscular or tree-like fashion, branching off dichotomously at predetermined junctions.

This is a type of mycorrhizal infection whereby the fungus in question invaginates the cell membrane of a plant cell, and branches in arbuscular manner.
Arum-type growth of hyphae is used in endomycorrhizal symbiosis with a plant.

Often, but not always, accompanied by intercellular hyphal growth.