A solitary, tall, water-loving, fast growing, dioecious, forest understorey, climbing palm. Not known in cultivation, locally common in the wild. It has a spiny, green stem, 30 m. (98 ft.) tall, 6 cm. (2.5 inch) diameter with no obvious leaf scars, and large segmented, pinnate (feather) leaves, 1.5 m. (5 ft.) long, 0.6 m. (2 ft.) wide, light green above and beneath. Flagella absent Cirri present.
This is the type specimen of Lanyu Island, Taiwan also the nearby Batan Islands of the Philippines. This rattan grows between 200 m. and 550 m. elevation on islands.
Calamus siphonospathus var. sublaevis naturally occurs on islands in moist forest, and is heavily effected by the surrounding sea temperatures, which are constant and often form sea mist and cloud. In this type of natural environment temperature fluctuations are slight, and this palm prefers a constantly hot and humid climate with little temperature difference between day & night, and Summer & Winter. This palm will not tolerate cool for very long.
Stems solitary, to 30 m long and 5 cm diameter (with leaf sheaths); leaf sheaths yellowish-brown, sparsely covered with needle-like, yellowish spines to 1 cm long; knee obscure; ocreas present, membranous; flagella absent; petioles to 20 cm long; pinnae to 50 per side of rachis, linear, regularly arranged, closely spaced to 2 cm apart; cirri present, to 1 m long. Inflorescence bracts open and diameter, yellowish-brown.
Can be found throughout the island, but very comon between 200-500 m. One needs to walk into the forest considerable distance from the paths to find mature specimens, as many have been cut by ratan cutters.