Calamus gibbsianus
Calamus gibbsianus is a species of rattan palm in the genus Calamus endemic to the Malaysian states of Sabah and Sarawak on the island of Borneo. It is a highly polymorphic species and reaches the highest altitude of any palm in Borneo, growing in montane forest at elevations of.
Description
Calamus gibbsianus is a slender, clustering montane rattan that climbs to, rarely more, and is very rarely more or less stemless. The stem measures in diameter without sheaths, and with sheaths. The internodes are short, rarely exceeding.The sheaths are dull mid to dark green, sparsely to densely armed with pale green spines up to long, occasionally also with minute spicules arranged in partial whorls. The sheaths and spines are all densely covered in brown indumentum. The knee is conspicuous, while the ocrea is inconspicuous to well developed, armed with groups of spicules or bristles. The flagellum reaches up to in length but is rarely absent.
The leaf is ecirrate, measuring up to on climbing stems, longer in stemless forms. The petiole is long and sparsely to densely armed. The rachis is covered with rusty-brown hairs. The leaflets are regularly arranged, with 6–20 on each side of the rachis, distant to crowded and lanceolate in shape. Mid-leaf leaflets measure by. The leaflets are usually very densely covered with minute spine-like papillae or short bristles on the undersurface and occasionally on the upper surface, always with a dense tuft of orange to red-brown hairs on the undersurface at the leaflet base.
The inflorescence is usually about long, with 1–4 partial inflorescences up to each. The inflorescence branches are strongly recurved and bear short recurved rachillae, large conspicuous saucer-like bracteoles, and relatively large flowers. The mature fruit is spherical to ovoid, measuring up to by, tipped by a short beak and covered in 15–18 vertical rows of pale brown, black-edged scales. The seed is ovoid to more or less oblong, up to by, deeply pitted and grooved, with subruminate endosperm. The seedling leaf is pinnate with about 6 leaflets.