Calamus heatubunii 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 : 68-70

4. Calamus heatubunii W.J.Baker & J.Dransf. , sp. nov. Type:— INDONESIA. West Papua Province: Kota Sorong,

Klasaman km 14, Klasagan, 50 m, 0°54’50”S, 131°21’32”E, 2 February 2013, Baker et al. 1392 (holotype K!, isotypes

AAU!, BO!, BRI!, L!, MAN!).

Diagnosis:— Distinguished by the few, broad, leathery leaflets, typically arranged in a single, divaricate group, the well-developed, purple-brown ocrea armed with numerous, solitary triangular spines, and the short, erect inflorescences lacking a flagelliform tip with compact, but not congested branching.

Moderately robust, clustering rattan climbing to 20 m. Stem with sheaths 11–18 mm diam., without sheaths 7–11 mm diam.; internodes 13–28 cm. Leaf ecirrate 70–90 cm long including petiole; sheath dark green, with caducous indumentum of matted grey hairs, soon falling, densely and evenly armed with solitary spines 2–4 × 0.5–1.5 mm, triangular, orange-brown tipped; knee 20–33 mm long, 9–12 mm wide, colour and indumentum as sheath, partially armed as sheath; ocrea 18–ca. 50 × 2–2.5 cm, boat-shaped, somewhat inflated and clasping, split to base on side opposite the petiole insertion, erect, papery, dark purple-green, drying brown, armed with numerous, scattered solitary spines similar to sheath spines, persistent, but eventually disintegrating; flagellum to 2.5 m long; petiole 20–26 cm, 5.5–9 mm wide and 3–4.5 mm thick at base, flattened adaxially, rounded abaxially, with indument and armature as sheath, with some solitary grapnel spines abaxially; leaflets 2–5 each side of rachis, broadly lanceolate, cucullate, glossy green, leathery, clustered in a single, divaricate group (typically of four leaflets) at the petiole apex (appearing digitate), less commonly an additional divaricate group of leaflets also present, apical leaflets 33–52 × 6–10 cm, apical leaflet pair united from one half to two thirds of their length, rachis extending conspicuously through the united portion of the terminal leaflet pair, remaining leaflets 32–50 × 5–9 cm, leaflet surfaces almost entirely unarmed, leaflet margins evenly armed with fine, stiff spines 1–2 mm long, leaflets lacking indumentum, transverse veinlets conspicuous. Staminate inflorescence erect, compact, held close to stem, ca. 35 cm long including ca. 9.5 cm peduncle, lacking flagelliform tip, branched to 3 orders; prophyll ca. 11 × 0.8 cm, narrowly tubular, indumentum not seen, armed as sheath; peduncular bracts lacking (prophyll subtending primary branch), rachis bracts 37–53 × 0.5–0.8 cm, narrowly tubular, with asymmetric, acute, distal limb, indumentum not seen, with very few spines as sheath; primary branches ca. 8, to ca. 14 cm long, ca. 4 cm apart, erect and appressed to main inflorescence, with up to ca. 30 rachillae, erect, held at acute angle with primary branch axis; rachillae 20–40 mm × 2–3 mm, straight or somewhat curved; rachilla bracts ca. 1 × 2–2.5 mm, distichous, openly funnel-shaped; floral bracteole ca. 1 × 2 mm, cup-shaped. Staminate flowers not seen. Pistillate inflorescence similar to staminate inflorescence, erect, compact, held close to stem, 22–33 cm long including 6–17 m peduncle, lacking flagelliform tip, branched to 2 orders; prophyll 10–20 × 0.7–0.8 cm, similar to staminate inflorescence; peduncular bracts lacking, rachis bracts similar to staminate inflorescence; primary branches 8, to 6 cm long, 13–25 mm apart, erect, appressed to main axis, with up to 9 rachillae; rachillae 21–37 mm × 3–5 mm, twisted; rachilla bracts 1.2–1.5 × 2 mm, distichous, funnel-shaped, mostly subtending floral dyads, but in some instances floral triads present at base of rachillae, apparently comprising one sterile staminate flower, and two pistillate flowers subtended by the proximal floral bracteole; proximal floral bracteole ca. 3 × 2 mm, distal floral bracteole ca. 2 × 2 mm, scar from sterile staminate inconspicuous. Pistillate flowers ca. 5 × 2.2 mm at anthesis; calyx ca. 2.2 mm diam., tubular in basal 3 mm, with 3 lobes to ca. 1 × 1.5 mm; corolla ca. 3.5 × 2.2 mm, tubular in basal ca. 2 mm, with 3 lobes to 1.5 × 1.5 mm; staminodes 6, 0.5–0.8 mm long, staminodial ring ca. 1 mm high; ovary ca. 1.5 × 1.7 mm, spheroidal, style 1 mm long, stigmas 1.5 mm long, strongly recurving. Sterile staminate flowers not seen. Fruit spherical, 13 × 10–11 mm including beak 1 × 1 mm, with 16–17 longitudinal rows of brown, dark margined, shallowly channelled scales. Seed (sarcotesta removed) ca. 8.5 × 7.5 × 4 mm, rounded, but bilaterally compressed and concave on one side, with irregular channels and ridges; endosperm homogeneous; embryo basal.

Etymology:— Calamus heatubunii is named for our friend and long-time collaborator in New Guinea palm research, Prof. Charlie D. Heatubun of Universitas Papua, Manokwari, Indonesia.

Distribution:— Recorded from several localities near to Sorong and from Waigeo in the Raja Ampat Islands in far western New Guinea.

Habitat:— Lowland forest, including secondary, hill and swamp forest, 45– 180 m.

Uses:— None recorded.

Vernacular names:— None recorded.

Specimens examined:— INDONESIA. West Papua Province: Sorong, Desa Klasaman, Lereng Bukit , 110 m, 0°55’S, 131°22’E, 12 November 1994, Maturbongs 33 ( K!, MAN) ; Sorong, Klasaman, km 24, Intimpura Camp , 180 m, 0°57’S, 131°27’E, 18 September 1995, Maturbongs 285 ( K!, MAN) ; Kota Sorong, Klasaman km 14, Klasagan , 50 m, 0°54’50”S, 131°21’32”E, 2 February 2013, Baker et al. 1392 (holotype K!, isotypes AAU!, BO!, BRI!, L!, MAN!), Baker at al. 1394 ( BO!, K!, L!, MAN!) ; Sorong, Makbalim Village, Aimas , 45 m, 1°4’S, 131°24’E, 1 July 1997, Maturbongs et al. 542 ( K!, MAN) ; Raja Ampat Islands, Waigeo Island, Waifoi Village , 50 m, 0°14’S, 130°50’E, 26 June 1997, Maturbongs et al. 516 ( MAN, K!)

Notes:— This species belongs to the Calamus lauterbachii group (also containing C. cheirophyllus J.Dransf. & W.J.Baker in Baker & Dransfield [2014: 189] and C. lauterbachii Beccari [1908: 491] ), which is characterised by strongly grouped, rather broad, leathery leaflets, conspicuous ocreas and rather compact inflorescences, sometimes with congested primary branching systems. Calamus heatubunii is a moderately robust species with very few leaflets, which are most often arranged in a single, divaricate group at the leaf apex. Its well-developed, purple-brown ocrea can reach ca. 50 cm in length and is armed with numerous, solitary triangular spines, similar to those found on the leaf sheath. The inflorescences are short, lacking a flagelliform tip, and erect, with compact, though not congested branching. It appears to be most closely related to the widespread species C. lauterbachii , which differs in the leaflets being more numerous, ocrea spines being organised in neat rows like eyelashes, the inflorescence bearing a flagelliform tip and congested primary branching systems, and the seed with shallower and less angular sculpturing. Calamus heatubunii also resembles C. cheirophyllus in the typically digitate arrangement of the leaflets and the erect, noncongested inflorescence, but this species is a montane taxon, that is much more slender in all its parts, with a fragile, unarmed papery ocrea that readily disintegrates.

Based on currently available records, the range of C. heatubunii does not overlap with that of the other two species. Calamus lauterbachii is widespread in New Guinea, but the most westerly record comes from the Arfak Mountains. Calamus cheirophyllus is known only from a few records in the Eastern and Southern Highlands of Papua New Guinea.