Volume 11 > Part 3 > Year 2013 > Page 382 > Arecaceae > Calamus

47. Calamus tenuis Roxb.wfo-0000760674

Fl. Ind. ed. 1832, 3: 780. 1832; Evans et al., A Field Guide to the Rattans of Lao PDR: 28. 2001.— Palmijuncus tenuis (Roxb.) Kuntze, Revis. Gen. Pl. 2: 734. 1891.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Densely clustering slender rattan. Stems climbing to 20 m long or more, without sheaths 0.8–1.6 cm diam., with sheaths to 2.5 cm diam., internodes to 20 cm long. Leaves ecirrate; sheaths bright green, with scattered mid-brown indumentum and abundant slightly reflexed narrow triangular brownish-black spines with yellowish swollen bases, variable in size, the longest to 2 cm, the spine bases with lateral margins swept down, spine margins hairy when newly emerged; knee conspicuous, armed as the leaf sheath or unarmed; flagellum up to 2.5 m long; ocrea inconspicuous, dry, unarmed; petiole 8–15 cm long, longer in juvenile stems, armed laterally and abaxially with dark spines with swollen yellowish bases; rachis 60–100 cm long, curved; leaflets up to 40 on each side of the rachis, regularly arranged, shiny, somewhat arcuate, linear-lanceolate, usually most bearing a short yellowish bristle on the upper surface of the main vein near to the insertion on the rachis, otherwise with three prominent veins bearing black bristles adaxially, the mid vein only bristly on abaxial surface, margins bristly. Inflorescences male and female superficially similar, the male branching to 3 orders, the female to 2 orders, to 2.5 m long, including the terminal flagellum, and bearing numerous well spaced partial inflorescences; male rachillae to 2.5 by 0.05 cm, female rachillae to 5 by 0.15 cm. Mature fruit ellipsoid, 1.4 by 0.8 cm, covered with 16–17 vertical rows of white or pale yellow scales with dark margins. Seed rounded, ca 0.9 cm diam.; endosperm shallowly ruminate.

Thailand : NORTHERN: Chiang Rai.

Distribution : Bangladesh (type), Indochina to Java.

Ecology : Alluvial soils, in open forests and village margins.

Vernacular : Wai chumphon (หวายชุมพน).

Uses: Edible shoot. Sometimes cultivated on a plantation scale for its fruit and shoots. Often receiving rudimentary cultivation in village margins for its cane for making boxes for serving sticky rice.

Conservation Status: Not threatened.

Notes: The curious short spine on the upper surface of the leaflets near the rachis seems to be diagnostic. The type of Calamus amarus Lour. has yet to be located for which reason its status as a synonym is indicated as provisional.