Calamus is a genus of flowering plants in the palm family Arecaceae that are among several genera known as rattan palms. There are an estimated 400 species in this genus, all native to tropical and subtropical Asia, Africa, and Australia. Description They are dioecious, mostly leaf-climbing lianas with slender, reedy stems. To aid scrambling some species have evolved hooks on the underside of the midrib, or more commonly by modified "pinnae" or tendrils in the form of stout, backward-pointing spines. These stems may grow to lengths of 200 metres. The fruits of certain species, in particular Calamus draco, produce a red resin known as "Dragon's blood". Species , Plants of the World Online recognises 415 species: Calamus acamptostachys (Becc.) W.J.Baker Calamus acanthochlamys J.Dransf. Calamus acanthophyllus Becc. Calamus acanthospathus Griff. Calamus acaulis A.J.Hend., N.K.Ban & N.Q.Dung Calamus adspersus Blume Calamus aidae Fernando Calamus albidus L.X.Guo & A.J.Hend. Calamus altiscandens Burret Calamus andamanicus Kurz Calamus anomalus Burret Calamus applanatus (A.J.Hend. & N.Q.Dung) A.J.Hend. Calamus arborescens Griff. Calamus aruensis Becc. Calamus arugda Becc. Calamus ashtonii J.Dransf. Calamus asperrimus Blume Calamus asteracanthus (Becc.) W.J.Baker Calamus ater (J.Dransf.) W.J.Baker Calamus australis Mart. Calamus axillaris Becc. Calamus bacularis Becc. Calamus badius J.Dransf. & W.J.Baker Calamus baiyerensis W.J.Baker & J.Dransf. Calamus balerensis Fernando Calamus balingensis Furtado Calamus banggiensis (J.Dransf.) W.J.Baker Calamus bankae W.J.Baker & J.Dransf. Calamus baratangensis Renuka & Vijayak. Calamus barbatus Zipp. ex Blume Calamus barfodii W.J.Baker & J.Dransf. Calamus barisanensis A.J.Hend. Calamus batanensis (Becc.) Baja-Lapis Calamus beccarii A.J.Hend. Calamus bicolor Becc. Calamus billitonensis Becc. ex K.Heyne Calamus bimanifer T.Evans, Sengdala, Viengkham, Thamm. & J.Dransf. Calamus boniensis Becc. ex K.Heyne Calamus bousigonii Pierre ex Becc. Calamus brandisii Becc. Calamus brevicaulis (A.J.Hend. & N.Q.Dung) W.J.Baker Calamus brevissimus A.J.Hend. Calamus brunneus A.J.Hend., Pitopang & Moh.Iqbal Calamus bulubabi W.J.Baker & J.Dransf. Calamus burckianus Becc. Calamus burkillianus Becc. ex Ridl. Calamus caesius Blume Calamus calapparius Mart. Calamus calciphilus A.J.Hend. Calamus calicarpus Griff. Calamus calospathus (Ridl.) W.J.Baker & J.Dransf. Calamus capillosus W.J.Baker & J.Dransf. Calamus carsicola Adorador & Fernando Calamus caryotoides A.Cunn. ex Mart. Calamus castaneus Griff. Calamus caurinus A.J.Hend. & Rustiami Calamus centralis A.J.Hend., N.K.Ban & N.Q.Dung Calamus ceratophorus Conrard Calamus cheirophyllus J.Dransf. & W.J.Baker Calamus ciliaris Blume Calamus cinereus A.J.Hend. & N.Q.Dung Calamus clivorum A.J.Hend. & N.Q.Dung Calamus cockburnii J.Dransf. Calamus compsostachys Burret Calamus comptus J.Dransf. Calamus concinnus Mart. Calamus concolor (Blume) W.J.Baker Calamus confusus (Furtado) W.J.Baker Calamus conirostris Becc. Calamus conjugatus Furtado Calamus conspectus W.J.Baker Calamus convallium J.Dransf.