Croquembouche columnare

The episoth is a tree with a highly evolved dispersal mechanism to spread its seeds near and far. The large spiny fruits grow from flowers all along the branches. When they are ripe they open explosively, flinging seeds in all directions. The seeds are covered in a mucilaginous substance, much like chia on earth that was used to make a 20th century product called “chia pets,” although the episoth mucilage is quite acidic. After the sticky seeds adhere to whatever they contact, such as other trees, animals, or Na'vi, the acidic mucilage begins to dissolve the surface layer. This creates a more suitable surface for the seeds to stick and begin germination. (Read more)
The Na’vi gather the seeds and collect the mucilage to use as a skin rejuvenation treatment. The seeds are delicious and used as a high-protein food source.