The gerilon trees are found primarily along the western coastlines, but their unique seed distribution system does mean they have been found across the empire. The gerilon trees have thin, flexible trunks and branches. Their ″leaves″ form as spherical orbs which contain gas. Many engineers theorise that these gas filled balloons serve a dual purpose. Firstly, they assist with generating energy and nutrients for the plant, and the gases can be harvested for a variety of purposes. Secondly, when the trees are fertilised towards the end of the summer, the gasses within the leaf balloons change substantially and the connections to the plant wither. The balloons turn reddish and eventually disconnect from the tree, the lighter than air gasses lift them high into the air with a small cargo of seeds. Some balloons only travel a short distance, while others will travel thousands of miles if strong winds catch them.

A Gerilon Tree
A Gerilon Tree

Source: Twilight Ramblings 10 - Flora of Anyaral (http://forum.worldoftwilight.com/index.php?topic=164.0)