Calamus papyraceus W.J.Baker & J.Dransf., 2017

Baker, William J. & Dransfield, John, 2017, More new rattans from New Guinea and the Solomon Islands (Calamus, Arecaceae), Phytotaxa 305 (2), pp. 61-86 : 78-80

9. Calamus papyraceus W.J.Baker & J.Dransf. , sp. nov. Type:— PAPUA NEW GUINEA. East Sepik Province: WewakAngoram area, Maprik Subdistrict, Prince Alexander Range, SE side of Mt. Turu above Ambakanja village, 600 m, 19

August 1959, Pullen 1506 (holotype CANB!, isotype LAE).

Diagnosis:— Distinguished by the slender habit, the regularly pinnate leaves, the leaf sheaths with collars of fine, caducous spines, the long, disintegrating papery ocrea armed with fine spines, the erect, congested inflorescence lacking a flagelliform tip with dry, papery bracts, erect primary branches and short pistillate rachillae, and typically conventional calamoid sympodial floral clusters producing a single fruit per cluster in the pistillate plant.

Slender rattan climbing to 6.5 m. Stem with sheaths 10–12.5 mm diam., without sheaths to 6–7 mm diam. Leaf ecirrate 0.7–2.5 m long including petiole; sheath pale brown when dry, with indumentum of scattered pale brown fibrous scales, densely armed with fine, brown, hair-like spines to 30 mm long, spines grouped in short whorls and fused into a ridge at the base; knee ca. 30 mm long, ca. 10 mm wide, rather weakly developed, same colour as, but less densely armed than the sheath; ocrea ca. 27 × 1.2 cm, erect, splitting longitudinally opposite the petiole insertion, papery, brown, armature similar to sheath, but less dense, with indumentum of pale brown and colourless fibrous scales, disintegrating into fibres; flagellum present, ca. 1 m long; petiole 14–26 cm, 4.5–6 mm wide and 4–5.5 mm thick at base, channelled adaxially, rounded abaxially, with thin, silvery indumentum of easily detached, colourless or brown, fibrous scales, margins armed with stout spines; rachis 0.5–2.3 m, armed with scattered grapnel spines abaxially; leaflets 15–22 on each side of rachis, arranged regularly, linear-lanceolate, longest leaflet at mid-leaf position, mid-leaf leaflets 20.5–46 × 1.5–2.2 cm, apical leaflets 10–26 × 0.6–1.5 cm, apical leaflet pair united to one third of their length, leaflets armed with conspicuous black bristles 1.5–5.5 mm on margins and major veins of both surfaces, leaflets largely glabrous or with some scattered indumentum as petiole, transverse veinlets conspicuous. Staminate inflorescence not seen. Staminate flowers not seen. Pistillate inflorescence erect, 49–65 cm long including 13–30 cm peduncle and 8–10 cm sterile tip, branched to 2 orders; prophyll 20–21 × 0.6–0.7 cm, tubular, but becoming paper and tattering deeply distally, indumentum as petiole, armed with whorls of fine brown spines similar to those on ocrea; peduncular bracts lacking, rachis bracts 8–18 × 0.5–0.7 cm, similar to prophyll, papery and tattering; primary branches 3–4, to 12 cm long, 6–12 cm apart, inserted at very acute angle, held erect and parallel to rachis, rather congested, with up to 7 rachillae, bracts funnel-shaped and armed with numerous short spines, papery (especially near apex); rachillae 17–35 × 2.5–3.5 mm, straight; rachilla bracts 4–5 × 2.5–3.5 mm, distichous, imbricate, funnel-shaped, acutely apiculate, papery and tattering at apex, indumentum as petiole, very dense around margins of young bracts, armed with numerous short spines, subtending a typical calamoid floral dyad (one triad observed in Pullen 1506 [CANB] containing scars of two pistillate flowers and a single staminate flower); proximal floral bracteole 4 × 3 mm, distal floral bracteole 2.5 × 2.5 mm, scattered brown scales on outer surface of bracteoles, scar from sterile staminate flower round. Pistillate flowers ca. 4 × 2.5 mm, material at or near anthesis not seen. Sterile staminate flowers not. Fruit spherical, ca. 13 × 9.5 mm including beak 2.5 × 1.5 mm, with ca. 21 longitudinal rows of yellow scales with brown margins. Seed (sarcotesta removed) 7 × 6 × 6 mm, globose with shallow lateral pit; endosperm homogeneous; embryo basal.

Etymology:— The species epithet refers to the papery texture of the ocrea and of the inflorescence bracts.

Distribution:— Known from a single locality near Mt. Turu in the Prince Alexander Range in East Sepik Province, Papua New Guinea.

Habitat:— Rain forest on steep, stony slope, 600–1000 m.

Uses:— None recorded.

Vernacular names:— Khaza (Ambakanja, Maprik), Ipis (Jal, Madang).

Specimens examined:— PAPUA NEW GUINEA. East Sepik Province: Wewak-Angoram area, Maprik Subdistrict, Prince Alexander Range, SE side of Mt. Turu above Ambakanja village , 600 m, 19 August 1959, Pullen 1506 (holotype CANB!, isotype LAE) ; Yangoru Subdistrict, southern slope of Mt. Turu , 1000 m, 3°36’S, 143°22’E, 1 November 1999, Marai & Kjaer 443 ( AAU!, LAE) .

Notes:— This species resembles a slender form of C. zebrinus Beccari (1908: 235) in the regularly pinnate leaves, leaf sheaths with collars of fine, brittle, caducous spines, and the long, erect papery ocrea that is armed with fine spines and disintegrates early. The two species also share some reproductive similarities, such as the funnel-shaped bracts on rachillae and other branches that are densely armed with minute spines. Calamus papyraceus is however markedly distinct in its smaller stature, shorter ocrea (to ca. 27 cm rather than ca. 1 m), in the erect, congested inflorescence to 65 cm lacking a flagelliform tip with papery, tattering bracts throughout (rather than the elongate, flagellum-like inflorescence to 6 m of C. zebrinus ), the erect primary branches held parallel to the inflorescence main axis (rather than the lax, open primary branches of C. zebrinus ), and the short pistillate rachillae to 3.5 cm (4.5 to 19 cm in pistillate C. zebrinus ). Importantly, Calamus papyraceus bears conventional sympodial floral clusters comprising a sterile staminate flower and a functional pistillate flower, thereby producing a single fruit per floral cluster, unlike Calamus zebrinus with its anomalous floral cluster with an additional pistillate flower resulting in paired fruits ( Dransfield & Baker 2003). It should be noted though that a single triad was observed in Pullen 1506 (CANB), which consisted of the scars of two pistillate flowers and a single staminate flower.