Calamus warayanus Adorador & Fernando, 2020

Calamus warayanus Adorador & Fernando , sp. nov.

Type:— PHILIPPINES. SAMAR, Samar Province, Paranas, Barangay Tenani , 388 m elev., 06 February 2016, Adorador 055 (holotype PNH! , isotype LBC! )

Diagnosis: —This rattan is most similar to C. microsphaerion Beccari (in Perkins 1904: 45) but differs in its clustering habit, axillary shoots emerging from cut stem, unarmed rachis below at the proximal half, much fewer and shorter lanceolate leaflets that is typically arranged in divaricate pairs, and relatively shorter rachillae of staminate inflorescence.

Clustering, very slender rattan, climbing to 10 m or more; stem with sheaths 4–9 mm diameter, without sheaths to 3 mm diameter; internodes 6–9.5 cm long. Leaf sheaths dull green, with sparse bulbous-based, narrowly-triangular, sometimes ± wavy, straw-coloured, laminar spines ave. 1.8 cm long, up to 2.5 cm long near leaf sheath mouth; knee bulged, generally unarmed; ocrea inconspicuous up to 2 mm long. Leaf cirrate, to 70 cm long, including very short petiole to 1.3 cm (typically shorter or absent) and cirrus at least 23 long cm; rachis yellowish, rounded on both surfaces, unarmed above, armed below on the up to at least the distal 1/2 its length, distally with single to 2–3 claws; cirrus armed with reflexed rigid spines below aggregated into grapnels; leaflets to about 15 on each side of the rachis, typically arranged in 2’s (rarely regularly arranged upon total exposure to light above the canopy) and spaced 3.8–7 cm apart, short linear-lanceolate, apices narrowly apiculate, 1-(sub 3-) costulate, green and concolorous on both surfaces, glabrous on either surfaces and along margins; transverse veinlets inconspicuous; proximal leaflets 5.2–9.5 × 0.4–1.3 cm; middle leaflets 5.7–13.6 × 0.5–1.3 cm; distal leaflets 4.6–13.2 × 0.4–0.7 cm, distal pair divergent. Inflorescence diverging from sheath way below the sheath apex. Staminate inflorescence arcuate, diffuse-paniculate, 43–78 cm long, branching to 3 orders, with up to c. 9 partial inflorescences (first order branches); peduncle 12 cm long, ca. 6 mm diameter at the insertion on the leaf sheath; prophyll tightly tubular to 6.8 cm long, unarmed; peduncular bract 1, 5.5–6.5 × 0.6 cm, similar to prophyll, other primary bracts on the axis similar but decreasing in size towards the apex, each subtending a partial inflorescence (first order branch); most proximal partial inflorescences to 22–60 cm long, arching, bearing equally-spaced unarmed bracts 3.5 × 0.5, each subtending a second-order branch which bears to ca. 14 rachillae; rachillae to 0.5–1.2 cm long (rarely longer, in most basal axes), arcuate, subtended by a bract 8 × 4 mm, with a short triangular limb, bearing up to 12 staminate flowers on each side, rather congested, rachilla bract to 1 mm long. Staminate flower to 3.5 × 2.5 mm, rounded in bud; calyx to 2 × 2 mm, lobes 3, apiculate, joined about half its length; corolla 3 × 2 mm; stamens 6, anthers dorsifixed, filaments to 1.5 mm long; pistillode minute. Pistillate inflorescence as the staminate but generally shorter, to 16–51 cm long and branched to 2 (rarely 3) orders only; prophyll up to 5.6 × 0.5 cm; peduncular bract 1, 3.2 × 0.4 cm; partial inflorescences 3 (rarely up to 9), the most proximal up to 14 cm long; primary branch bract up to 2.7 × 0.2 cm; bracts subtending rachillae 4 × 2 mm, with triangular limbs; rachillae up to 4–5 on each side of the axis, each 1.6–4 cm long, with up to 6 pistillate flowers on each side of the axis. Pistillate flower not seen. Fruit and seed not seen. ( Figures 4 View FIGURE 4 & 5 View FIGURE 5 ).

DISTRIBUTION. Endemic to the Philippines (Samar Island) ( Figure 6 View FIGURE 6 ).

SPECIMENS EXAMINED:— PHILIPPINES —SAMAR: Samar Province, Paranas, Tenani , 18 July 2015, J.T. Adorador 022 ( LBC!), 388 m elev., 06 February 2016, J.T. Adorador 055 (holotype PNH! , isotype LBC! ), 056 ( EBL! LBC!) , 057 ( LBC!, K!) , 058 ( LBC!) .

HABITAT AND ECOLOGY:— Among the karst peaks surveyed, it is only found around the summit of a single karst formation (388 m elev.) in Tenani, Paranas, Samar. It occurs abundantly on the forest floor and canopy of the said summit. The canopy of the surrounding vegetation is about 5–20 m high which is dominated by spindly trees (ave. 10- 20 cm diam.). Other Calamus species thriving sympatrically with this new species include C. discolor , C. multinervis [= C. moseleyanus in Henderson (2020)], and C. ochrolepis .

CONSERVATION STATUS:— Critically Endangered [CR B2 a, b(iii, iv)]. The area of occupancy (AOO) is estimated to be just 4 km 2. In the survey of one 20 m × 20 m nested plot in the type locality, we recorded just 38 palm individuals (13 mature, 17 saplings and 8 seedlings) ( Adorador 2016 unpublished data). The said locality has relatively intact forest cover but the low number of mature individuals makes this species very susceptible to extinction, even though it has the capability to produce plantlets on cut stems.

ETYMOLOGY:— The specific epithet comes from the terms ‘ Waray ’ which refers to the people inhabiting the islands of Samar, (northern) Leyte and (eastern) Biliran who speaks the Waray-waray language and – anus, a suffix to indicate a sense of belonging or possession ( Stearn 1983). This new rattan is named in their honor, especially to the field guides and local community leaders on Samar Island who helped in various ways during the field surveys.

VERNACULAR NAME:— It is locally known as ‘ pudlos-liitan ’ (Waray) ( Adorador & Fernando 2017). Despite its similarity with other slender rattans locally referred as ‘ pudlos ’, it is said to be the most diminutive hence the term ‘ liitan ’ or ‘small’.

USES:— This rattan is uncommonly utilized as tying material or as clothesline.

NOTES:— This new rattan is most similar to Calamus microsphaerion in its cirrate leaf which typically bears fanned leaflets in definite groups, and staminate inflorescence branched up to three orders. However, C. warayanus differs in its clustering habit (solitary in C. microsphaerion ), formation of axillary shoots in cut stems (undocumented in C. microsphaerion ), very slender stem (typically more robust in C. microsphaerion ), unarmed rachis below up to proximal half of its length (armed with recurved hooks from the leaf base in C. microsphaerion ), fewer and significantly shorter lanceolate leaflets (up to 15 per side of rachis measuring 5.7–13.6 × 0.5–1.3 cm in middle leaflets vs. 19–50 linear-lanceolate leaflets and 15.5–31.5 × 0.5–4.7 cm in C. microsphaerion ) which are typically arranged in divaricate pairs (arranged groups of 3–7 in C. microsphaerion ) and relatively shorter rachillae in staminate inflorescence (up to 1.2 cm vs. 4–6 cm in C. microsphaerion ). Among the specimens examined, two collections from Mindoro Island deposited at EBL (O. Barile, M. Dimayuga & Co. 639) and at LBC (E.S. Fernando 724 – cultivated at MBG) are arguably the nearest to C. warayanus based on over-all appearance; however details of vegetative and reproductive features refer to that of C. microsphaerion .

Likewise, a very similar species to C. microsphaerion , C. malawaliensis J. Dransfield (1982: 805) , deviates from the new species in its spinier sheath and rachis, the proximal leaflets being the largest (middle leaflets being the largest in C. warayanus ), and significantly shorter pistillate rachillae (up to just 1 cm vs up to 4 cm in C. warayanus ). It is very probable that the sterile collection (D.A. Madulid 1003) labelled as C. malawaliensis from Puerto Princesa in Palawan Island is indeed, a C. microsphaerion .

The formation of axillary shoots through cut stems is hitherto undocumented (or simply overlooked) for Calamus in the Philippines, while only the aerial and internodal suckering and branching is reported in C. merrillii ( Fernando 1987) . Similar shoot formation has been documented in other Southeast Asian rattans, but only those that produce plantlets from inflorescence tips ( Dransfield 1992, 1997; Henderson & Khou 2013). This asexual mode of reproduction may explain their abundance on the summit of limestone karsts and could be capitalized for their mass propagation.