Calamus orientalis C. E. Chang; C. quinquesetinervius Burret.

Stems clustered, climbing, to 20 m, 3-5 cm in diam. Leaf sheaths yellowish brown, densely covered with flattened, yellowish, upward-pointing spines to 2 cm; ocreas short or absent; knees prominent, swollen, spiny; flagella absent; petioles short or absent; rachis to 2 m with 18 or 19 broadly lanceolate pinnae per side, these irregularly arranged (regularly arranged on young plants), distantly spaced; middle pinnae 30-45 cm, 3-5 cm wide at mid-point, adaxial veins and margins bristly; cirri to 1.5 m. Inflorescences to 1.2 m, flagellate; inflorescence bracts tightly sheathing. Fruits yellowish brown, pedicellate, ellipsoid, to 2 × 1 cm.

● Lowland rain forests; below 1000 m. Taiwan.