An elongated circumferential

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

base formation present on some species of

palm Palm most commonly refers to: * Palm of the hand, the central region of the front of the hand * Palm plants, of family Arecaceae **List of Arecaceae genera * Several other plants known as "palm" Palm or Palms may also refer to: Music * Palm (ba ...

is called a crownshaft. The leaf bases of some pinnate leaved palms (most notable being ''

Roystonea regia ''Roystonea regia'', commonly known as the Cuban royal palm or Florida royal palm, is a species of palm that is native to Mexico, parts of Central America and the Caribbean, and southern Florida. A large and attractive palm, it has been planted ...

'' 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.Riffle, Robert L. and Craft, Paul (2003) ''An Encyclopedia of Cultivated Palms''. Portland: Timber Press. / The crownshaft takes the form of a column above the main trunk and beneath the main crown of leaves and is nothing but the collection of the leaf bases of the plant, all tightly wrapped around one another. 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. Each layer of the crownshaft is a distinct leaf base and is usually made of a tough fibrous material with a feel similar to leather and in many parts of the world, it is cured and used to prepare covers, sheets and roofing material. The leaf base of some palms are also used to extract

coir Coir (), also called coconut fibre, is a natural fibre extracted from the outer husk of coconut and used in products such as floor mats, doormats, brushes, and mattresses. Coir is the fibrous material found between the hard, internal shell ...

. 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. These scars usually fade over time and the distance between two successive scars is an approximate indicator of the speed of growth of the palm. In tropical conditions when growing conditions are good, the palm grows faster and the gap between scars is large; conversely when growing conditions are not optimum, plant growth is slow and the gaps are narrower. Juveniles and younger palms usually grow faster than adults; this is demonstrated by the larger gaps between scars at the base as compared to the top. 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.

Gallery

Image:Roystoneashaft.jpg, Crownshaft on a mature

royal palm ''Roystonea regia'', commonly known as the Cuban royal palm or Florida royal palm, is a species of palm that is native to Mexico, parts of Central America and the Caribbean, and southern Florida. A large and attractive palm, it has been planted ...

Image:crownshaft.JPG, Crownshaft on a

Dominican Republic The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares wit ...

References

Arecaceae Plant morphology {{palm-stub