Description from Flora of China
Calamus banlingensis Cheng Y. Yang, Zheng H. Yang & J. Lu; C. doriaei Beccari; C. giganteus Beccari var. robustus S. J. Pei & San Y. Chen; C. inermis T. Anderson; C. inermis var. menghaiensis San Y. Chen, S. J. Pei & K. L. Wang; C. khasianus Beccari; C. multinervis Beccari var. menglaensis San Y. Chen, S. J. Pei & K. L. Wang; C. nambariensis var. alpinus S. J. Pei & San Y. Chen; C. nambariensis var. furfuraceus S. J. Pei & San Y. Chen; C. nambariensis var. menglongensis S. J. Pei & San Y. Chen; C. nambariensis var. xishuangbannaensis S. J. Pei & San Y. Chen; C. nambariensis var. yingjiangensis S. J. Pei & San Y. Chen; C. obovoideus S. J. Pei & San Y. Chen; C. palustris Griffith var. longistachys S. J. Pei & San Y. Chen; C. platyacanthoides Merrill; C. platyacanthus Warburg; C. platyacanthus var. longicarpus San Y. Chen & K. L. Wang; C. platyacanthus var. mediostachys S. J. Pei & San Y. Chen; C. polydesmus Beccari; C. wailong S. J. Pei & San Y. Chen; Palmijuncus inermis (T. Anderson) Kuntze.
Stems clustered, climbing, to 30 m, to 6 cm in diam. Leaf sheaths green with light brown hairs, with scattered to densely arranged, yellowish brown, triangular, flattened, downward-pointing spines to 3.5(-9) cm, often interspersed among shorter spines, or sometimes spines absent; ocreas present; knees prominent; flagella absent; rachis to 4 m with 36-40 lanceolate pinnae per side, these clustered or regularly arranged; middle pinnae 40-55 cm, 2.5-7 cm wide at mid-point, margins bristly; cirri to 2.5 m. Inflorescences to 2 m, not flagellate; inflorescence bracts tubular. Fruits whitish to yellowish brown, globose to ovoid or ellipsoid, to 2.4(-3.4) × 2.5 cm, stalked, scales grooved.
This species provides a high-quality cane used in furniture-making and binding. It has been introduced into other areas for trial plantings.
Calamus nambariensis is very variable and difficult taxonomically, and it represents a species complex. It is morphologically similar to C. palustris, which does not occur in China, and the two can be distinguished reliably only by the female inflorescences and fruits. Calamus nambariensis has been treated in local floras as consisting of several distinct species. The characters used to separate these species are based mostly on leaf sheath spines or their absence, leaflet arrangement, and fruit size. Here, only one species is recognized, although many local forms are likely to be encountered, and the complex is greatly in need of a modern revision. There are also nomenclatural problems. The widely accepted name used here, C. nambariensis, is not the oldest name, which is C. inermis T. Anderson (J. Linn. Soc., Bot. 11: 11. 1869). However, Evans et al. (Kew Bull. 57: 53-54. 2002) are followed here, and this name is used pending a revision of the whole complex. The FRPS record (13(1): 98. 1991) of C. palustris var. cochinchinensis Beccari is probably based on a misidentification of material belonging to this complex.
Lowland or montane rain forests; below 2000 m. Yunnan [Bangladesh, Bhutan, India, Laos, Myanmar, Nepal, Thailand, Vietnam].