Korthalsia hispida Becc.

Vernacular

Wi Asas, Wi Semut (Ib.)

Distribution

Known from scattered localities throughout Brunei at altitudes up to 300 m above sea level. Elsewhere throughout Borneo though never common; very local in Sumatra and Peninsular Malaysia.

Biology

K. hispida tends to occur in disturbed forest on steep slopes - e.g. on old land slips or along steep-sided river valleys in lowland and hill dipterocarp forest at altitudes up to 900 m above sea level.

General Description

Clustering moderate rattan with stems to 30m branching in the canopy; stem without sheaths to 1.5 cm diam., with sheaths to 2.5 cm diam., internodes to 12 cm long. Sheaths bright green, with deciduous chocolate-coloured scales, sparse black spines to 2.5 cm and sparse black brittle spicules; ocrea very conspicuous to c. 25 × 5 cm, diverging from the stem at an acute angle, the two edges inrolled, armed with black spines to 2.5 cm, abundant black brittle spicules and deciduous chocolate-coloured scales; ants usually abundant and very noisy. Leaf to 1.5 m including cirrus to 75 cm and petiole to 20 cm; leaflets up to 7 on each side of the rachis, very shortly stalked, to 25 × 10 cm, bright green on upper surface, whitish beneath. Inflorescences produced from topmost 2-4 nodes, crowded but not forming a head; bracts densely covered in chocolatecoloured scales and black spicules; rachillae few, large, to 20 × 1.5 cm, with conspicuous bracts. Fruit rounded to somewhat oblong, to 2.2 × 1.9 cm, shortly beaked, covered in 15 vertical rows of reddish-brown scales. Seed ovoid to 1.4 × 1.2 cm; endosperm homogeneous. Seedling leaf not known. (Fig. 9, Pl. 1B).

Shahimi, S., Conejero, M., Prychid, C.J. et al. (2019). A taxonomic revision of the myrmecophilous species of the rattan genus Korthalsia (Arecaceae). Kew Bulletin 74: 69. https://doi.org/10.1007/s12225-019-9854-x

Type

Indonesia, Sumatra, 1 Aug. 1878, Beccari PS 643 (holotype FI!: isotype K!).

Morphology General Habit

Moderately robust, clustering rattan climbing to 20 m

Morphology Stem

Stem with sheaths 11 – 25 mm diam., without sheaths 8 – 10 mm diam.; internodes 10 – 20 cm

Morphology Leaves

Leaf 1.15 – 2.0 m long including cirrus and petiole; sheath bright green, with caducous, brown-coloured indumentum, sheath armed with scattered abundant, black, needle-like spines, spine 2 – 30 mm long, c. 1 mm wide; ocrea 18.5 – 30.0 × 3.0 – 4.5 cm, conspicuous, diverging from the angle at stem just above the petiole, the margins tending to inroll, papery, brown, armed with 3 – 30 mm long black spines and abundant chocolate spicules, abundant black fierce and very noise ants nested within the ocrea; cirrus 0.5 – 1.0 m, armed with recurved grapnel spines organised in whorls; petiole 10.0 – 35.0 cm, 10 – 20 mm wide and 3 – 5 mm thick at base, flattened adaxially, abaxially rounded, with brown indumentum, sparsely armed with fine spines as sheath; rachis 0.30 – 1.07 m, armed with recurved grapnel spines; 5 – 8 leaflets each side of rachis, regularly arranged, rhomboid, mid-leaf leaflets 15.0 – 19.6 × 5.0 – 8.6 cm, leaflet dull to light green above, glabrous, with caducous, whitish indumentum on undersurface, distal margin conspicuously praemorse, transverse veinlets moderately conspicuous and moderately spaced, 1.0 – 1.5 mm

Morphology Reproductive morphology Inflorescences

Inflorescence lax to congested, 30.0 – 50.2 cm long including c. 45 mm peduncle, branched to (1 –) 2 orders; prophyll 4.5 × 1.0 cm, with caducous, dark brown indumentum with scattered tiny spines; rachis bracts up to 8.3 – 9.5 × 2.6 – 3.4 cm, conspicuous, inflated and splitting, with caducous, dark brown indumentum and densely covered with chocolate scales and black spicules; primary branches 1 – 4, 4.0 – 6.6 cm apart; proximal primary branch 17.0 – 27.5 cm long, with up to 1 – 3 rachillae; rachillae 11.5 – 22.3 cm long and slender, stalk not visible, 1.0 – 1.8 cm wide, lacking hairy between rachilla bracts

Morphology Reproductive morphology Flowers

Flower 8 – 8.1 × 3.3 – 3.7 mm in the bud

Morphology Reproductive morphology Fruits

Fruit round to oblong, 1.8 – 2.3 × 0.9 – 1.6 cm covered in 15 – 18 vertical rows of reddish-brown scales

Morphology Reproductive morphology Seeds

Seed 1.1 × 0.8 cm; endosperm homogeneous

Distribution

Malay Peninsula, Borneo (Brunei, Sabah, Sarawak, East and South Kalimantan), Sumatra

Ecology

Along steep-sided river valleys in lowland and hill dipterocarp forest at altitudes up to 900 m above sea level.

Vernacular

Rotan semut (Iban), Paikat ayah pipit (Dayak Lawangan), Wi asas (Iban), Wi semut (Iban), Lesat (Lundaya), Uwai saar (Kenyah), Uei sanam (Kenyah), Laku sepuru (Punan), Ohot (Dayak Tunjung).

Note

Korthalsia hispida and K. robusta are the only two myrmecophilous species in Korthalsia with ocreas that do not clasp the stem, but diverge at an acute angle just above the petiole. These two species are the noisy rattans. The ocreas of K. hispida are inhabited by ants of the genus Camponotus (Mattes et al. 1998). The ants make a rhythmic, hissing noise by banging their mandibles against the ocrea when the plant is disturbed. Korthalsia hispida can be distinguished from K. robusta by the presence of black spicules on the ocrea and sheaths.

Use

Fibre for the plaiting of baskets, craft and binding constructions.