Calamus tadulakoensis Henderson, Iqbal, Rusydi & Pitopang, 2018

Henderson, Andrew, Iqbal, Moh., Rusydi, Muhammad & Pitopang, Ramadhanil, 2018, A new species of Calamus (Calaminae, Calamoideae, Arecaceae) from Sulawesi, Indonesia, Phytotaxa 345 (3), pp. 298-300 : 298-300

Calamus tadulakoensis Henderson, Iqbal, Rusydi & Pitopang sp. nov. ( Fig. 1 ).

Type:— INDONESIA. Sulawesi Tengah: Banggai Regency, Lamala District, road from Labotan to Boloak, disturbed forest on steep slope, limestone soil, 00˚52.520’ S, 123˚14.423’ E, 146 m, 7 October 2017, A. Henderson & Moh. Iqbal 4258 (holotype BO, isotypes CEB, K, NY).

It differs from similar species ( C. leiocaulis , C. suaveolens ) in its regularly arranged pinnae that are grayish-white indumentose abaxially.

Stems solitary, climbing, 5.0–30.0 m long, 3.0– 4.2 cm diameter. Leaf sheaths tubular, closed opposite the petiole, with a knee below the petiole; leaf sheath spines stout, triangular, concave at the base proximally, horizontally spreading, dense, yellowish-brown; ocreas short, membranous, spiny, extending into an acute apex above the petiole; flagella absent; petioles 2.0–15.0 cm long; rachises 2.0 m long, the apices extended into an elongate cirrus without well-developed pinnae, adaxially flat, abaxially with irregularly arranged, closely spaced, solitary or clustered dark-tipped, recurved spines, terminating in a shallow groove adaxially; pinnae 15 per side of rachis, regularly or slightly irregularly arranged, elliptic, with spinules on veins adaxially, grayish-white indumentose abaxially, the lateral veins diverging then converging, both terminating apically or slightly subapically; proximalmost pinnae swept back across the sheath; middle pinnae 38.5–56.0 cm long, 5.5–6.3 cm wide. Inflorescences diverging from sheath well below sheath apex, with two vertical ridges distal to point of divergence; inflorescences arching, slender and elongate, usually without recurved spines, terminating in a long, tubular structure in line with the main inflorescence axis and covered with overlapping bracts; partial inflorescences not stalked, with a pulvinus in axil of rachis and partial inflorescence; partial inflorescences with elongate rachis bracts, recurved rachises, and rachillae subtended by short, funnel-shaped, equally long rachillae bracts (i.e., rachis bracts and rachillae bracts strongly dimorphic); rachis bracts tubular but not closely sheathing the rachis, abruptly narrowed proximally; rachillae sessile; staminate inflorescences not recorded; pistillate inflorescences branched to 2 orders, 2.45 m long; pistillate rachillae 12.0–15.0 cm long, with dyads of 1 pistillate and 1 neuter flower, the dyads arranged in alternate rows along recurved rachillae but not opposite so that one side of rachillae without dyads, borne on short, stout pedicels; fruits globose to ellipsoid, 12.0 mm long, 8.0 mm diameter, whitish; fruiting perianths tubular; fruit scales channeled vertically; seeds 1 per fruit, basally attached, small, globose, with a ventral depression, reniform in longitudinal section, the dorsal surfaces pitted, covered with a tanniniferous, non-fibrous sarcotesta; raphe branches 2, bifurcating from the attachment of seed and running along ventral side; endosperm homogeneous; embryos at or near base of seed.

Distribution and habitat:—Eastern Sulawesi in lowland rainforest on limestone soils at 146 m elevation.

Taxonomic notes:— Calamus tadulakoensis is a member of the C. adspersus species group. It is, as far as we know, confined to limestone soils in eastern Sulawesi.

The specific epithet honors Tadulako University, our research base. The term ‘tadulako’ is also a common term in the region of Central Sulawesi, meaning a person of good virtue, wisdom, courage, and morals.

Additional specimen examined. INDONESIA. Sulawesi Tengah: Banggai Regency, Lamala District, road from Labotan to Boloak, disturbed forest on steep slope, limestone soil, 00˚52.520’S, 123˚14.423’E, 146 m elevation, 6 October 2017, A. Henderson & Moh. Iqbal 4256 (BO, CEB, K, NY).

Figures

FIGURE 1. Calamus tadulakoensis. A. Cirrus with irregular spines. B. Grayish-white indumentose abaxial pinna surface. C. Leaf sheath with non-spiny knee. D. Fruits borne on short, stout pedicels.