Calamus fertilis Becc., Ann. Roy. Bot. Gard. (Calcutta) 11(1): 492 (1908)

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Map uses TDWG level 3 distributions (
New Guinea present (World Checklist of Arecaceae)B
Apparently widespread in lowland New Guinea but not often collected. Also recorded from Manus Island. (Dransfield, J. & Baker, W.J. 2003: An Account of the Papuasian Species of Calamus (Arecaceae) with Paired Fruit)A


  • Calamus fertilis is one of the largest of all rattans in New Guinea. It is easily distinguished by its robust ecirrate leaves with regularly arranged leaflets, long flagella and its fiercely armed sheaths with massive, grossly swollen knees that are usually unarmed and with particularly large, orange or bright yellow, downward- pointing spines just below the knee. Until recently, Calamus fertilis was known only from three pistillate rachillae in Beccari's palm herbarium in Florence, with a fragment also in the Bailey Hortorium. These rachillae were described and illustrated by Beccari (1908) as bearing quadrads of flowers, each comprising two pistillate flowers and two sterile staminate flowers. We re-examined the type in Florence in 2002 and were surprised to discover no trace of quadrads in the rachillae - within the flower groups, only a single central scar is visible, marking the position of the fallen sterile staminate flower. We cannot imagine how Beccari could have been misled into depicting quadrads rather than groups of three, unless he perhaps thought there should have been a sterile staminate flower for each pistillate flower. As far as we know, the only New Guinea rattan that has quadrads of flowers is C. altiscandens Burret, but in the one and only fertile specimen the occurrence of quadrads is rare. Furthermore, the form of the rachillae in C. altiscandens is quite different from that of C. fertilis. The rachillae of C. fertilis match perfectly those of the large rattan from lowland New Guinea described here and we have at last been able to name what proves to be a common, widespread species and simultaneously remove the name Calamus fertilis from the list of names of uncertain application. (Dransfield, J. & Baker, W.J. 2003: An Account of the Papuasian Species of Calamus (Arecaceae) with Paired Fruit)A

Biology And Ecology

  • In lowland forest, usually on river banks or in swamp forest at altitudes up to 450 m above sea level. (Dransfield, J. & Baker, W.J. 2003: An Account of the Papuasian Species of Calamus (Arecaceae) with Paired Fruit)A


  • Least concern. (Dransfield, J. & Baker, W.J. 2003: An Account of the Papuasian Species of Calamus (Arecaceae) with Paired Fruit)A

Common Name

  • pokou (Gulf), hurumau (Kerema), kema (Yamur) (Dransfield, J. & Baker, W.J. 2003: An Account of the Papuasian Species of Calamus (Arecaceae) with Paired Fruit)A


  • Local uses not recorded. (Dransfield, J. & Baker, W.J. 2003: An Account of the Papuasian Species of Calamus (Arecaceae) with Paired Fruit)A


  • Very robust, solitary or clustering rattan climbing to 30 m. Stem with sheaths 31 - 45 mm diam., without sheaths to 18 - 32 mm diam.; internodes 13 - 32 cm. Leafecirrate, to 1.8 - 2.54 m long including petiole; sheath pale green to yellowish green, drying mid brown, usually with very sparse indument, sometimes with abundant grey indument between and on spines; spines persistent, very dense and of various sizes, orientation and form, most abundant spines 2 - 8 x 1 - 3 mm, horizontal, narrow triangular, laminar or papery, interspersed with much longer usually downward pointing golden or orange spines 30 - 40 x 1.8 - 2.3 mm and very large strictly downward-pointing spines 62 - 110 x 3 - 8 mm inserted just below the knee; knee very conspicuous, grossly swollen, 53 - 78 x 28 - 45 mm, yellowish green, usually unarmed, or very sparsely armed (in Poudyal et al. 92 rather densely armed as the sheath); ocrea 2.5 - 13 x 4 - 6 cm, entire at first, with a shallow cleft next to the petiole, soon tattering and usually disintegrating into a mass of fine pale fibres, sometimes the margins remain unsplit, the abaxial surface of the whole ocrea rather densely armed with slender spines to 5 mm, or unarmed; flagellum present, to 6- 8 m long; petiole 20 - 40 cm long, 13 - 23 mm wide, 7 - 11 mm thick at the base, adaxially flattened or shallowly channelled, abaxially rounded, with sparse to dense grey indument, and with scattered, rigid, persistent spines to 7 mm long along the margins and adaxial face, usually absent from a broad mid-band abaxially but sometimes with a row of broader triangular spines along the mid line; rachis to 214 cm long, arcuate, armed with recurved hooks abaxially, glabrous or with sparse grey indument; leaflets 53 - 65 on each side of rachis, regularly arranged, lanceolate, longest leaflet near the middle of the leaf 28 - 56 x 1.3 - 3.2 cm, apical leaflets 9 - 15 x 0.5 - 1.0 cm, apical leaflet pair united to 1/10 - 1/2 of their length, leaflets armed with long pale, darker based bristles to 10 mm long along 3 veins adaxially and with slightly shorter bristles along mid-vein abaxially, leaflets lacking indument, transverse veinlets conspicuous. Staminate inflorescence to 4 m long including peduncle to 58 cm and flagelliform tip to 90 cm, branched to 3 orders; prophyll 60 x 2.1 cm, closely sheathing, remaining ± entire with a triangular tip, with sparse grey indument and armed along margins with sparse slender spines to 25 mm long; peduncular bracts absent; rachis bracts similar to prophyll but shorter, generally unarmed and with sparse indument; primary branches up to 6 in number, to at least 60 cm long, c. 30 - 50 cm apart, with numerous rachillae; rachillae 5 - 11 x 0.2 cm; rachilla bracts 2 x 0.8 mm, distichously arranged, with patchy brown indument, unarmed; floral bracteole 0.5 x 0.5 mm, triangular, unarmed, with patchy brown indument. Staminate flowers 3 x 1 mm, known only as dry, old flowers. Pistillate inflorescence, similar to staminate inflorescence, to 4.4 m long including peduncle to 45 cm and flagelliform tip to 75 cm, branched to 2 orders; prophyll 45 x 1.4 cm, closely sheathing, remaining entire, with a triangular tip, with sparse grey indument; peduncular bracts absent, rachis bracts similar to prophyll but smaller, closely sheathing, mostly unarmed; primary branches 6 - 9, to 75 cm long, 15 - 30 cm apart, with up to 22 rachillae, subtending bracts unarmed or with few scattered short triangular spines; young rachillae 3 - 13 x 0.2 cm, rachillae in fruit 15 - 26 x 0.3 - 0.5 cm; rachilla bracts 20 - 24, 5 x 4 mm, distichous, unarmed, with sparse grey indument and dark irregular-margined scales; proximal floral bracteole 1 x 1 mm, distal floral bracteole 1 x 1 mm, scar from sterile staminate c. 1 mm diam. Pistillate flowers borne in pairs together with a sterile staminate flower to form a triad of flowers; early pistillate buds c. 2 x 1.5 mm; calyx to 3.5 mm, tubular in basal 2 mm, with triangular lobes; petals c. 2 x 1.5 mm; perianths enlarging to c. 5 mm long, splitting and becoming explanate in fruit. Sterile staminate flowers 2 x 1.5 mm in bud, similar to staminate flower. Fruit ovoid, 11.5 - 18 x 7.5 - 10 mm including beak 1.5 - 2 x 1.5 - 2 mm, with 15 - 18 vertical rows of pale yellowish to dull mid brown, channelled scales with dark or pale margins and dark tips. Seed 8 - 10 x 5.5 - 8 x 4.5 - 7 mm, ellipsoid, rather deeply scalloped and pitted, with a shallow to deep chalazal pit; endosperm homogeneous; embryo basal. (Dransfield, J. & Baker, W.J. 2003: An Account of the Papuasian Species of Calamus (Arecaceae) with Paired Fruit)A

Materials Examined

  • INDONESIA, PAPUA. Mimika: Timika, Mile 21 Freeport Concession, Feb. 1998, Dransfield et al. JD 7669 (BO, K, L, MAN); Fak Fak: Etna Subdistr., Jepre R., Yamus, Feb. 2000, Maturbongs 673. PAPUA NEW GUINEA. Central: Port Moresby, Kuriva R., Jan. 1973, J. Gore & Bonikan NGF36540 (LAE); Kerema, near Murua School, May 1989, Poudyal et al. 83 (K); Kerema, Siraura, May 1989, Poudyal et al. 85 (K); 3 km from Brown R., May 1989, Poudyal et al. 92 (K). Gulf: Kikori Distr., Kikori R., Nov. 2000, Baker et al. 1125 (AAU, K, L, LAE NY); Malalua Subdistr., Omei R., Nov. 1972, Zieck & Kumul 36527 (BH, CANB, L). Manus Island: Manus, 1989, Mente 12, 21, 23, 27 (all K). Milne Bay: Mt Dayman, Armit s.n. (holotype Bt, isotypes FI, BH (fragment)). Northern: Kokoda, Kokoda Valley, Jan. 1973, Zieck 36543 (BH, CANB, L); Kokoda, March 1936, Carr 16298 (BH, BM, BO, BRI, K, L, LAE, SING). Southern Highlands: Kantobo, Mubi R., Feb. 1996, Baker et al. 648 (LAE, K). Western: N Fly Distr., Tabubil, Dec. 2000, Baker et al. 1126 (AAU, K, LAE); Balimo Subdistr., Arauia R., Dec. 1971, Zieck 36304 (BH, BRI, CANB, L). (Dransfield, J. & Baker, W.J. 2003: An Account of the Papuasian Species of Calamus (Arecaceae) with Paired Fruit)A


    A. Dransfield, J. & Baker, W.J. 2003: An Account of the Papuasian Species of Calamus (Arecaceae) with Paired Fruit
    B. World Checklist of Arecaceae