The pineal gland gets its name because it sorta looks like a pine cone, or a pine tree.
In Taoist schools of cultivation, it is referred to as the "Niwan palace" - I guess because it sorta looks like a palace.
I read in the Zhuan Falun, a book by Li Hongzhi, that scientific research found that the pineal gland contains the right parts for processing what is received by an eye - perhaps proof for a third eye, or just a vestigal feature.
I also read in his book that scientific research proved plants have feelings.