Crownshaft

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An elongated circumferential leaf base formation present on some species of palm is called a crownshaft.

The leaf bases of some pinnate leaved palms form a sheath at the top of the trunk surrounding the bud where all the subsequent leaves are formed.^[1]

It takes the form of a column above the main trunk and beneath the main crown of leaves. It is usually green in color but may be a different color from that of the leaves themselves, including white, blue, red, brownish or orange.

The oldest leaf forms the outermost layer of the crownshaft. Eventually the lowest palm frond dies back, the outer layer of the crownshaft splits, the leaf unwraps and pulls away from the trunk exposing the new crownshaft surface. In time the old leaf separates at the base and falls away leaving the distinct rings and ridges of the leafbase scars seen on the trunks of many species of palm.

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.

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