Description from Flora of China
Calamus collinus Griffith; C. erectus var. birmanicus Beccari; C. erectus var. collinus (Griffith) Beccari; C. erectus var. macrocarpus (Griffith) Beccari; C. erectus var. schizospathus (Griffith) Beccari; C. macrocarpus Griffith; C. schizospathus Griffith; Palmijuncus collinus (Griffith) Kuntze; P. erectus (Roxburgh) Kuntze; P. macrocarpus (Griffith) Kuntze; P. schizospathus (Griffith) Kuntze.
Stems clustered, non-climbing, free standing or sometimes leaning, to 6 m, to 5 cm in diam. Leaf sheaths dark green with dark brown hairs, with short rows of brown, flattened spines to 3.5 cm; ocreas present, with rows of short spines, split into 2, soon falling; knees absent; flagella absent; petioles and rachis with whorls of yellow spines; rachis to 3 m with up to 40 lanceolate pinnae per side, these regularly arranged; middle pinnae 60-80 cm, 3.5-5 cm wide at mid-point, adaxial and abaxial veins and margins bristly; cirri absent. Inflorescences to 2 m, not flagellate; inflorescence bracts tubular, tattering at apices. Fruits greenish- or reddish brown, ellipsoid, 3-5 × 2-2.5 cm, scales grooved.
This species provides a short, thick, non-flexible cane used in construction and furniture-making.
Lowland or montane rain forests or drier forests usually on steep slopes; below 1400 m. Yunnan [Bangladesh, Bhutan, India, Laos, Myanmar, Nepal, Thailand].