Description from Flora of China
Cornera Furtado; Palmijuncus Kuntze; Rotang Adanson; Rotanga Boehmer; Schizospatha Furtado; Zalaccella Beccari.
Stems clustered or less often solitary, mostly slender and climbing, occasionally non-climbing and then either short and subterranean or free standing. Leaves 10-60, pinnate, spiny; sheaths closed in climbing stems, open in non-climbers, variously hairy and spiny, hairs of young sheaths soon wearing off; sheath spines scattered or densely arranged (rarely absent), or arranged in rows, occasionally hairy on margins, variously shaped and colored, sometimes arranged in overlapping, interlocking rings and forming chambers; sheath apices usually extended above point of insertion of petiole into an inconspicuous or prominent ocrea; knees present in climbing stems; flagella present in climbers, whiplike and armed with small, grapnel-like spines; cirri present in few species (and then flagella absent, and vice versa); pinnae variously arranged and shaped, occasionally whitish or gray on abaxial surfaces. Plants dioecious. Inflorescences usually elongate, branched to 3 orders, male inflorescences more branched than female ones; branches and rachillae covered with overlapping bracts with clawed spines on outer surfaces in climbers; male flowers borne along opposite sides of rachillae; female flowers borne in pairs with a sterile male flower, along opposite sides of rachillae. Fruits mostly small, variously shaped and colored, usually 1-seeded, sometimes pedicellate, always covered with overlapping scales, these sometimes with a groove down middle; endosperm homogeneous or ruminate; germination adjacent; eophylls bifid or pinnate.
Calamus palustris Griffith (Calcutta J. Nat. Hist. 5: 60. 1845) has been reported from China, but no reliable fertile material has been seen (Henderson, Palms S. Asia, 80. 2009). Calamus latifolius Roxburgh (Hort. Bengal. 73. 1814) has been recorded from China as well (e.g., in Govaerts et al. 2010. World Checklist of Arecaceae. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/ accessed 6 May 2010); however, the species group to which it belongs is complex and not well understood, so the record is thought to be best excluded.
About 385 species: from W Africa, India, and Sri Lanka through S and SE Asia to Australia and the Pacific islands; 28 species (15 endemic) in China.