Obesus brevis

The puff daddy is a close relative of the puffball tree, although it is a large shrub. Under the fluffy pink covering are small globular balls that are quite sponge like. However, almost as soon as they are produced they are covered by a pink colored fungus, growing in a symbiotic relationship with the puff daddy. The fungus absorbs atmospheric nitrogen and converts it to nitrate, which is then absorbed by the globular balls of the puff daddy. The plant obtains from the fungus the nitrogen in the form it needs for growth, while the fungus obtains carbohydrates from the plant for its growth. (Read more)
The fungus is quite delicious and used by the Na’vi for food. They are careful not to harvest too much off one plant to avoid destroying the balance between plant and fungus required to maintain the health of both.