Spanish moss is not a moss, but a flowering plant (Tillandsia usneoides) often seen draped from the branches of live oaks, cypress, and other large trees in the southeastern United States. The trees on which it grows provide support but no nutrients or moisture—the plant provides those things for itself, without apparently harming its support tree. This, then, is an example of a:

The correct answer is: Commensalism.

Explanation:

Commensalism can be defined as a type of interaction between two species living in the same habitat of an ecosystem.In this type of interaction, one of the species derive benefit from the other species while the other species remain unaffected, that is, it is neither capable of drawing any benefit from the interaction nor is harmed due to the interaction.In the given question, Spanish moss which is a flowering plant derives only support (benefit) from the large trees by growing on their branches. They are capable of producing their own food by self-derived nutrients and moisture.On the other hand the large tree just holds the flowering plant on its branch. In the process, it neither gains anything nor is harmed (unaffected).