Calamus baiyerensis 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 : 61-63

1. Calamus baiyerensis W.J.Baker & J.Dransf. , sp. nov. Type:— PAPUA NEW GUINEA. Western Highlands Province:

Baiyer River Subdistrict, Rouna River (Baiyer River valley) near Kambukom village, 1160 m, 5°35’S, 144°10’E, 23

July 1971, Zieck NGF 36252 (holotype CANB!, isotypes BH, LAE).

Diagnosis:— Distinguished by the very robust, clustering habit, the sparsely armed sheath with patchy dark indumentum, the ocrea encircling the stem that disintegrates into fibres and the very robust inflorescence with robust rachillae with funnel-shaped bracts.

Very robust, clustering rattan climbing to ca. 20 m. Stem with sheaths 45–55 mm diam., without sheaths to 15–18 mm diam.; internodes at least 18 cm, complete material not seen. Leaf ecirrate to 1.7 m long including petiole; sheath green, with patchy indumentum of densely matted, minute, brown-black hairs, sparsely armed with solitary, planar, triangular spines to 10 × 2 mm, sheath unarmed in parts; knee ca. 80 mm long, ca. 28 mm wide, colour and indumentum as sheath, unarmed; ocrea to ca. 18 cm long, encircling stem, tattering and disintegrating into dry, brown fibres, unarmed; flagellum present, 5–8 m long, very robust; petiole at least 15 mm wide and 10 mm thick at base, flat to convex adaxially, rounded abaxially, glabrous, armed laterally with stout spines; rachis armed with pale, black-tipped, robust grapnel spines; leaflets 32–35 each side of rachis, regularly to subregularly arranged, linear-lanceolate, longest leaflets near base 60 × 3.5 cm, mid-leaf leaflets 55 × 3.5 cm, apical leaflets 26 × 1.4 cm, apical leaflet pair united to one quarter of their length, unarmed abaxially, with scattered black bristles on adaxial surface of two major lateral veins, with scattered bristles to 2 mm on margins, especially near tip, transverse veinlets moderately inconspicuous. Staminate inflorescence very robust, only incomplete material seen, branched to 3 orders; prophyll and peduncular bracts not seen, rachis bracts up to at least 32 × 13 cm, tubular and tattering at mouth, armed with grapnels as flagellum; primary branches at least 58 cm long, recurving sinuously, with numerous rachillae, bracts tubular, tattering, unarmed; rachillae 15–43 mm × 5–6 mm, robust, bilaterally compressed; rachilla bracts ca. 2.5 × 5 mm, distichous, funnel-shaped, apiculate; floral bracteole cup-shaped with two distinct keels. Staminate flowers ca. 3 × 2 mm, dry remains only present. Pistillate inflorescence not seen. Pistillate flowers not seen. Sterile staminate flowers not seen. Fruit not seen.

Etymology:— The species epithet reflects the type locality in the Baiyer River valley.

Distribution:— Known only from the type locality in the Baiyer River valley, Western Highlands Province, Papua New Guinea.

Habitat:— Disturbed mid-montane forest, 1200 m.

Uses:— None recorded.

Vernacular names:— Kela or Sintsch (Baiyer River valley).

Specimens examined:— PAPUA NEW GUINEA. Western Highlands: Baiyer River Subdistrict, Rouna River (Baiyer River valley) near Kambukom village, 1160 m, 5°35’S, 144°10’E, 23 July 1971, Zieck NGF 36252 (holotype CANB!, isotypes BH, LAE).

Notes:— Here we describe two closely related species of robust, montane rattans, Calamus baiyerensis and C. pintaudii . They both occur at relatively high elevations and share features such as well-developed, disintegrating ocreas and robust inflorescences with robust rachillae bearing prominent, funnel-shaped rachilla bracts. The two can be distinguished by their spines, which are very few and triangular in C. baiyerensis , compared to very numerous and needle-like in C. pintaudii , and by the ocrea, which is encircling, straw-coloured and tattering to fibres in C. baiyerensis , rather than membranously papery, fragile, dark brown and cleft opposite the petiole in C. pintaudii . The leaflets of C. baiyerensis are similar in length to those of C. pintaudii , but are around twice the width and are less densely bristly on their margins (especially at the leaflet tip). Although the inflorescences are similar, the primary branches of C. baiyerensis appear to be longer, but with shorter rachillae than C. pintaudii . Calamus baiyerensis is known from a location just beyond the western limit of C. pintaudii . It is possible that the two represent different dimensions of a broader complex, but the available material supports the recognition of two species at this point.

The presence of a well-developed ocrea and funnel-shaped bracts potentially links these taxa to Calamus nanduensis Baker & Dransfield (2014: 198) , C. pseudozebrinus Burret (1935: 319) and C. womersleyi Baker & Dransfield (2014: 211) , all of which are recorded from moderate to relatively high elevation (700–1500 m). There is also some similarity in inflorescence morphology with C. sashae J.Dransf. & W.J.Baker in Baker & Dransfield (2014: 205), but this is not an ocreate species.