Sentinel Fan is flora in Avatar: Frontiers of Pandora and is found growing throughout the Clouded Forest.
The sentinel fan grows from a base of short serrated leaves, from which seven highly elastic stems protrude, webbed with a rubbery membrane. Both the stems and membranes are distinctly patterned, which can most clearly be seen when its bioluminescence is active.
On sensing movement, these stems extend rapidly, expanding the plant's distinctive 'fan' to more than double its resting size. This response is a deimatic startle display, evolved to deter predators from eating or trampling this plant.
The sentinel fan grows in clusters, often in a row. This plant is closely related to the Helicoradian; and although it displays the opposite threat response -- expanding instead of contracting -- both plants share near identical root and cell structures.
The 'fan' of the plant itself is sturdy and pliable, and the Kame'tire Clan harvests the membrane and uses it to wrap meats, for storage and cooking.
Once used, the sentinel fans and their seeds are often discarded in areas where useful mosses and lichens are found, encouraging the sentinel fan to grow there. The plant then acts as both a deterrent to herbivores which might eat them, and a marker to help locate invaluable medicines.