Calamus arborescens Griff.

Moderate to robust clustering erect rattan showing no tendency to climb. Stems to 10 m long, 6.5 cm diam., internodes short, to 10 cm long. Leaf ecirrate; sheaths green, open and tubular only at the base, armed densely with scattered or partially whorled flattened black spines, to 4 cm long; ocrea present; knee absent; flagellum absent; petiole 0.5–1.5 m long, densely armed with flattened black spines to 8. cm long, arranged in partial whorls; rachis to 2.5–4 m long; leaflets 25–90 on each side of the rachis, regularly arranged, ± lanceolate, adaxially dark green, abaxially with a dense layer of whitish indumentum, the largest to 100 x 6 cm. Inflorescences to 2.5 m long, without terminal flagellum, male and female superficially similar, the male branched to 3 orders, the female to 2 orders; primary bracts splitting and tattering at their tips; partial inflorescences up to 15, to 60 cm long; male rachillae 12–19 x 0.3 cm, female to 18 x 0.4 cm. Fruits obovoid to ellipsoid, to 2.2 x 0.5 cm, briefly beaked and covered in 12 vertical rows of reddish brown deeply channelled scales. Seed 1.2 x 0.6 cm, irregularly pitted; endosperm homogeneous. Seedling leaf not recorded.