Caryota is a genus of palm trees. They are often known as fishtail palms because of the shape of their leaves. There are about 13 species native to Asia and the South Pacific. One of the more widely known species is Caryota urens, which yields sap used to make an unrefined sugar called jaggery, and also to make palm wine. They are also one of the few Arecaceae with bipinnate foliage. Many grow in mountainous areas and are adapted to warm mediterranean climates as well as subtropical and tropical climates.
The leaves or fronds are very long (up to 7m) with very distinctive fishtail shaped leaflets.
The whole plant contains needle-like calcium oxalate crystals which if chewed or eaten can produce a burning sensation in the mouth. Skin contact can result in burning, itching and dermatitis.
I have not experienced any of the negative aspects of this plant.
When I planted this species 20 years ago I did not know that it was a declared weed!