Calamus radiatus

Calamus radiatus is a climbing palm that stays green year-round. It belongs to the Arecaceae family. Its common names include rattan, Rotan Rays, and Radial Leaf Rotan. It comes from southwestern Sri Lanka. The climate there is wet and tropical. It grows in damp forests in the lowlands. Known sites lie below about 984 feet [300 metres]. This species also has the name Palmijuncus radiatus. Useful Tropical Plants lists it as a wild plant.

This palm climbs; it does not form a free-standing tree. Its long stems stay thin and do not branch. Curved prickles hook onto nearby plants to help it climb. The stems reach up to about 197 feet [60 metres] long. Useful Tropical Plants also lists a height of 164 feet [50 metres]. Neither figure gives a normal size for garden plants. The canes are just 5–7 millimetres thick, close to pencil thickness. The plant keeps its leaves all year.

Its native home points to a plant of warm, damp forests. Plants For A Future lists USDA hardiness zones 11–12. The sources give no light or soil advice for this species. Much of the care text covers the whole genus. It should not serve as firm advice for this species. Useful Tropical Plants states that male and female plants grow apart. Both sexes must grow together to yield fruit and seed. The sources give no season for blooms. Nor do they say how the flowers or fruit look.

People use the stems for several kinds of craft work. They weave baskets and use the stems to tie things together. Past accounts describe baskets that held tea leaves just picked. Workers split the canes into thin strips for chair seats. Once split, the strips can bend enough for this use. Twisted cane can also form strong ropes for towing. Thin strips form frames for hats made in Sri Lanka. These uses explain the plant's value as a source of fibre.

The sources do not show which, if any, parts people can eat. Plants For A Future gives it an edibility score of zero. It also gives it a medicinal score of zero. Useful Tropical Plants reports no known use as medicine or known hazard. That hazard entry does not prove safety for people or pets. Take the prickles into account when you handle this palm. The sources name no specific pests or diseases that affect it.