Tsawlapxangrr (short form: tsawlapx) - tall large root
Up to 9 meters
|Behind the scenes|
The unidelta tree, closely related to the delta tree, has one important difference. Its leaves are not toxic; however, it roots are highly toxic. When the two species of tree grow close together, their roots form connections underground and the toxin from the unidelta tree passes on to the delta tree, making its roots toxic as well.
These two Magellum species have coevolved with a mutualistic relationship that benefits them both. The unidelta tree shares its root toxin with the delta tree, which does not need to expend energy making its own, and the delta tree shares nutrients with the unidelta tree. The only sign that toxin has been transferred is a subtle change in the bioluminescense of the tree leaves at night, which the Na'vi have learned to identify. Animals have also learned to avoid feeding on the roots of both trees, making it an excellent defense mechanism for both plants. 
The unidelta tree wood is harvested to make canoes, and the thick, waxy leaf cuticle is melted down and used for waterproofing. The leaves themselves, which are non-toxic, are then used to make bowls, since they are naturally waterproofed. The spines are then used by the Na'vi to make tools, as well as weapons for hunting and fishing. Because of their close array, the unidelta tree is the tree of choice for a performance of the pendulum drums.
The wood is also used for the construction of log drums, because a certain species of insect often drills pathways through the wood. This gives the wood an exceptionally resonant quality. The leaves can be used in banshee meat wraps.