An elongated circumferential leaf base formation present on some species of palm is called a crownshaft. The leaf bases of some pinnate leaved palms (most notable being Roystonea regia or the royal palm but also including the genera Areca, Wodyetia and Pinanga) form a sheath at the top of the trunk surrounding the bud where all the subsequent leaves are formed. In some species of palm the shaft is fairly indistinct because the leaf bases are not wrapped around each other very tightly, and the shaft becomes extended and “loose.” Some palm species do not form a shaft until past the juvenile stage.