Calamus nuralievii Henderson & Nguyen Quoc Dung, 2018

Henderson, Andrew & Dung, Nguyen Quoc, 2018, New species and subspecies of Calamus (Arecaceae) from Vietnam, Phytotaxa 347 (4), pp. 251-262 : 259

Calamus nuralievii Henderson & Nguyen Quoc Dung sp. nov.

Type:— VIETNAM. Kon Tum: Kon Plong District, Thach Nham Protected Forest, 17 km N of Mang Den Town, 14°45’S 108°17’E, 1420 m, 7 June 2016, M. Nuraliev, A. Kuznetsov & S. Kuznetsova 1658 (holotype NY!, isotype MW n.v.). Fig. 5 .

It differs from Calamus poilanei in its irregularly arranged pinnae that lack abaxial spinules (versus regularly arranged pinnae with long spinules abaxially) and staminate inflorescences branched to 2 orders (versus 3 orders).

Stems branching not recorded, climbing, length and diameter not recorded. Leaf sheaths tubular, closed opposite the petiole, with a knee below the petiole, mottled with irregular bands of tomentum; leaf sheath spines stout, triangular, concave at the base proximally, downward pointing, scattered, yellowish-brown; ocreas short, membranous, non-spiny, forming an irregular ring but usually open or reduced above the petiole, splitting early; flagella not recorded; petioles length not recorded; rachises length not recorded, the apices filiform or sometimes just a short stub between the distal pair of pinnae; pinnae number not recorded, irregularly arranged, lanceolate, usually with spinules on veins abaxially, the lateral veins approximately parallel, one terminating subapically, leaving a distinct, adaxial ‘broken’ vein; middle pinnae 49.3(46.4–52.0) cm long, 2.1(1.8–2.5) cm wide; distal pair of pinnae join not recorded. Inflorescences diverging from sheath near sheath apex, with two diverging ridges distal to point of divergence; inflorescences arching, slender, elongate, with solitary or grouped, recurved spines on rachis and rachis bracts abaxially, terminating in a flagellum-like apex; partial inflorescences not or rarely stalked, with a pulvinus in axil of rachis and partial inflorescence; rachis bracts tubular, narrow, persistent, closely sheathing the rachis, not swollen at the apex, sometimes partially splitting if the partial inflorescence inserted below the bract apex; rachillae sessile; staminate inflorescences branched to 2 orders, length not recorded; staminate rachillae 3.5(2.0–5.0) cm long; staminate flowers arranged in alternate, opposite rows; staminate flowers sepals shorter than the petals, cupular, 3-lobed at the apex; stamens 6; filaments uniseriate, inflexed at the apex; pistillate inflorescences branched to 2 orders, length not recorded; pistillate rachillae 8.5(6.0–11.0) cm long, with dyads of 1 pistillate and 1 neuter flower arranged in alternate, opposite rows; fruits ellipsoid, mature size and color not recorded; fruiting perianths explanate; fruit scales scarcely channeled vertically; seeds 1 per fruit, basally attached, shape not recorded, the dorsal surfaces ridged or grooved, covered with a tanniniferous, non-fibrous sarcotesta; raphe branches not recorded; endosperm homogeneous; embryos position not recorded.

Distribution and habitat:—Central Vietnam in montane rainforest at 1500(1420–1580) m elevation.

Taxonomic notes:— Calamus nuralievii is similar to C. poilanei but differs in its irregularly arranged pinnae that lack abaxial spinules, and staminate inflorescence branching.

Additional specimens examined. VIETNAM. Kon Tum: Kon Plong District, Thach Nham Protected Forest, 17 km N of Mang Den Town , 14°52’S 108°17’E, 1580 m, 18 April 2015, Nuraliev , Kuznetsov & Kuznetsova 1387 ( NY) ; same locality, 1450 m Nuraliev, Kuznetsov & Kuznetsova 1659 ( NY) ; same locality, 1550 m, Nuraliev , Kuznetsov & Kuznetsova 1660 ( NY) .

Figures

FIGURE 5. Calamus nuralievii A. Leaf sheaths mottled with irregular bands of tomentum, with short, triangular, downward pointing, scattered, yellowish-brown spines (Nuraliev et al. 1659). B. Leaf with irregularly arranged pinnae (Nuraliev et al. 1660). C. Pistillate rachilla with dyads arranged in alternate, opposite rows (Nuraliev et al. 1660). D. Ellipsoid fruits (Nuraliev et al. 1658). (Images by M. Nuraliev).