Calamus carsicola Adorador & Fernando, 2020

Calamus carsicola Adorador & Fernando , sp. nov.

Type:— PHILIPPINES. SAMAR, Eastern Samar Province, Taft, Barangay San Rafael , 255 m elev., 10 February 2016, J.T. Adorador 072 ( holotype PNH! , isotypes K! , LBC! ).

Diagnosis: —This species is is distinguished from Calamus discolor Martius (1838: 341) in its more slender habit, leaf sheath with scattered straw-coloured acicular spines over thin grayish-white scurfy indumentum, shorter thinly scarious ocrea, very short petiole, fewer leaflets per side of rachis that is furnished above with short bristles along the proximal part of the midrib, apical leaflet pair joined up to half of its length and each segment being relatively the broadest leaflet along the rachis, less-branched pistillate inflorescence, and non-cupular persistent calyx.

Clustering, very slender rattan, climbing to at least 8 m; stem with sheaths to 9 mm diam., without sheaths 4–7 mm diam.; internodes to 14 cm long. Leaf sheaths dull green, polished with grayish-white scurfy indumentum with rather few scattered solitary slender, acicular, straw-coloured spines, typically less than 2.4 cm long, up to 3.8 cm along margins near the mouth; flagellum at least 1 m long; knee slightly bulged, generally unarmed; ocrea 3.5–4.5 cm long, thinly scarious, readily tattering into fibers. Leaf ecirrate, to 29.5–45 cm long, petiole absent or very short to ave. 5 mm long, 3 mm wide; rachis flat then bifacial distally above and armed with stout rigid spines up to 4 mm long which extends into lower portions of leaflets’ midrib, concave then flat distally below and armed with single recurved claw which diminish towards the apex; petiole and rachis of leaves near shoot apex usually covered with sparser grayish-white to light brown scurfy indumentum; leaflets 11–16 on each side of the rachis, regularly arranged and spaced 2.7–3.3 cm apart, linear-lanceolate to slightly obovoid, apices ± apiculate, 1-(sub 3-)costulate, green above and white below, armed with very short bristles along the margins and mid-vein on the adaxial surface, and rather smooth or rarely with bristles on distal portions along midrib on the abaxial surface; transverse veinlets inconspicuous; proximal leaflets 5.4–11.5 × 0.4–1 cm; middle leaflets to 13.7–18 × 1–1.7 cm; apical leaflets to 10–14 × 1.2–2 cm joined up to 2–5.7 cm at their bases or at least about 1/3 their length. Inflorescence diverging from sheath near the sheath apex. Staminate inflorescence erect or arcuate, 47–63 cm long, weakly flagelliform, branching to 2 orders (or up to 3 orders in most basal axes), main axis and rachis armed with up to 2 mm downward-pointing spines; with up to 3 partial inflorescences (first order branches), 12–19 cm apart; peduncle up to ca. 27 cm long, 0.5 cm diameter at the insertion on the leaf sheath; prophyll tightly tubular 12.5–26 cm long, sparsely armed as the sheath; peduncular bract absent; other primary bracts on the axis similar but decreasing in size towards the apex, covered with whitish scaly indumentum and with short slender spines grouped along vertical portion below the limb, each subtending a partial inflorescence (first order branch), most proximal partial inflorescence to 9–11 cm long, erect to slightly arcuate, gradually decreasing in length towards apex of main inflorescence axis, bearing equally-spaced unarmed bracts to 2.3 × 0.3 cm, each subtending rachillae, with up to ca. 10 rachillae on whole axes; rachilla to ca. 3.6 cm long, arcuate, bearing up to 11 staminate flowers on each side, rather congested, rachilla bract less than 1 mm long. Staminate flower to 3 × 2 mm, somewhat pointed in bud; calyx lobes 3, each 1.5 mm, striate, apiculate, joined to basal half; corolla tubular with 3 striate, apiculate lobes to 2 mm high; stamens 6, anthers dorsifixed, filaments to 1.5 mm long; pistillode minute. Pistillate inflorescence as the staminate but generally shorter, to 43.5–47 cm long and branched to 2 orders only, with 1(–2) partials to 7.5 cm long, main axis and rachis armed with up to 2 mm downward-pointing spines; primary branch bract 1.6 × 0.2 cm, each subtending 4–5 rachillae, each to 1.7 cm long, with up to 6 pistillate flowers on each side of the axis; proximal floral bract 2 mm wide, distal floral bract 1.8 mm wide, rachillae bract to 5 mm long, with triangular limbs. Pistillate flower not seen, persistent calyx in immature fruits 2 × 2 mm, fused-cylindrical truncate and non-cupular in basal half, 3-parted in upper half. Fruit yellowish-green, narrowly-obovoid, 1 × 0.5–0.7 cm, stigmatic remains forming a 2 mm high cylindrical beak, with up to 16 vertical series of scales, grooved along the middle, margins ± lacerate; immature seed plano-convex, 5 × 3 × 1.5 mm, the convex side with rough surface, the plane side ridged; endosperm seemingly homogenous. ( Figures 1 View FIGURE 1 & 2 View FIGURE 2 ).

DISTRIBUTION:— Endemic to the Philippines ( Samar and Siargao Islands) ( Figure 3 View FIGURE 3 ).

SPECIMENS EXAMINED:— PHILIPPINES. SAMAR: Eastern Samar Province, San Rafael , Taft, 255 m elev., 10 February 2016, J.T Adorador 072 ( holotype PNH !, isotypes LBC! , K! ), 15 June 2019, J.T. Adorador 133 ( PNH!, CAHUP!, K!) . SIARGAO: locality not known, June 1919, M. Ramos & J. Pascasio 34833 ( US! [ US00013173 ], P! [ P02147169 ], K!)

HABITAT AND ECOLOGY:— On Samar Island, it occurs near the summits of karst formations (ave. 250 m elev.) in San Rafael, Taft, Eastern Samar. The populations encountered thrive well on edges near forest clearings. The canopy of the surrounding vegetation is about 15–20 m high which is formed by large-diameter (ave. 50–60 cm diam.) trees. Other Calamus species observed occuring sympatrically include C. discolor , C. merrillii [(= C. zollingeri subsp. merrillii in Henderson (2020))], C. multinervis [= C. moseleyanus in Henderson (2020)], C. ochrolepis , and C. symphysipus .

CONSERVATION STATUS:— Critically Endangered [CR B2 b(iii, iv, v) c(iv)]. The area of occupancy (AOO) in Samar and Siargao Islands is estimated to be just 8 km 2. Limited palm surveys in Samar Island Natural Park (SINP) last February 2016 in two 20 m × 20 m nested plots in the type locality, altogether recorded just 21 palm individuals (14 mature and 7 saplings) ( Adorador 2016 unpublished data). The low number of mature individuals and continued forest disturbance caused by illegal poaching of forest products ( e.g. for fuel wood, drift woods, and ‘agarwood’ ( Aquilaria spp. ) only aggravate its survival in the wild.

ETYMOLOGY:— The specific epithet comes from ‘ Carsus ’, the Latin term for ‘karst’ ( Kranjc 2011) and ‘– icola’, a suffix which means ‘a dweller’ ( Stearn 1983); which refers to its preference to the limestone karst habitat.

VERNACULAR NAME:— The local guides specifically referred to this palm as ‘ pudlos-uban ’ (Waray). Around Samar Island, the term ‘ pudlos ’ is also applied to several slender rattans such as C. elmerianus [= C. mitis in Henderson (2020)], C. filispadix , and C. usitatus ( Adorador & Fernando 2017) ; while ‘ uban’ translates to ‘white hair’, in this case the white indumentum on abaxial side of leaflets.

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

NOTES:— The new rattan only resembles C. discolor in its flagellated leaf sheath, conspicuous ocreas, ecirrate leaf with regularly-arranged discolorous leaflets (green above and white below, but later caducous in C. carsicola ). However, C. carsicola is readily distinctive in its scattered straw-coloured acicular spines on the leaf sheath (denselyset longer dark brown acicular spines in partial whorls in C. discolor ), the leaf sheath (and all other axes) covered in grayish-white scurfy indumentum (densely appressed with reddish brown lepidote or wooly hairs in C. discolor ), shorter and thinly scarious ocrea (up to 4.5 cm vs. longer membranous papery up to c. 20 cm in C. discolor ), very short petiole (just 0.5 cm vs. with distinct petiole 4.7–35 cm long in C. discolor ), fewer leaflets per side of rachis (just 11–16 vs. 20–50 per side in C. discolor ) that is furnished above with short bristles especially along the proximal part of the midrib (typically, with bristles along three nerves above and on midrib below in C. discolor ), apical leaflet pair joined at least 1/3 of its length (unfused and divergent in C. discolor ) and each segment being relatively the broadest leaflet along the rachis (relatively narrower than middle segments in C. discolor ), shorter (up to just 47 cm long) flagelliform pistillate inflorescence with few (4–5) rachillae per partial (vs. 63–150 cm long bearing up to 20 rachillae per partial in C. discolor ), and the fused cylindrical truncate non-cupular calyx in fruit (conspicuously bulged cupular in C. discolor ). Notably, the novel species is nearest to the diminutive forms of C. discolor that were collected from highelevation serpentine habitats of Mt. Redondo on Dinagat Island ( E.S. Fernando 4216B at LBC) and Mt. Hamiguitan in southeastern Mindanao Island ( E.S. Fernando 1634 at LBC), but C. carsicola can be easily separated by the characters stated above.

Meanwhile, the little-known C. discolor var. negrosensis Beccari (1909: 635) ( variety not recognized in Henderson 2020) differs from C. carsicola in its more spiny sheath, the leaflets being bristly on just the midnerve above and 3–5 nerves below, and the apical leaflet pair being divergent and not fused. It is noteworthy that the type specimen of C. discolor var. negrosensis ( Danao FB 12432 at FI) consists of the distal portions of its leaf while the staminate inflorescence clearly belongs to C. aidae Fernando (1988: 49) . This conclusion is supported by the examination of recent collections of C. aidae comprising leaf materials near the type locality of C. discolor var. negrosensis in Negros Island ( A. Baja-Lapis 620 at EBL – hence a new island record) and a staminate inflorescence from Samar Island ( J.T. Adorador 061 at LBC) which is hitherto unknown. Several sterile specimens conforming the leaf of C. discolor var. negrosensis have been collected from limestone habitats on islands of Cebu ( D.A. Madulid & E.J. Reynoso 5054 deposited at PNH) and Masbate ( E.S. Fernando & B.D. Arizala 333) and from cultivated plant in MBG deposited at LBC ( E.S. Fernando 1819). Although apparently distinct from the typical C. discolor , we refrain from formally elevating it to species level until complete fertile collections are made and examined.

Other closely-related rattans with discolorous leaflets include C. aidae and C. bicolor Beccari (1913: 126) . However, these rattans differ from the new species in their much robust non-flagellate leaf sheaths, dense acinaciform spinescence in partial whorls, subcirrate (in C. aidae ) or cirrate (in C. bicolor ) leaves with very numerous leaflets, and much larger inflorescences.