Calamus subinermis

Calamus (KAL-ah-muhs) subinermis (suhb-ee-NEHR-miss)
Luasong, Sabah, Malaysia. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.
Scientific Classification
Genus: Calamus (KAL-ah-muhs) Species: subinermis (suhb-ee-NEHR-miss)
Synonyms
None set.
Native Continent
Asia
Morphology
Habit: Solitary & clustering Leaf type: Pinnate
Culture
Survivability index
Common names
"rotan batu"

Habitat and Distribution

Borneo, Philippines, and Sulawesi. Confined to offshore islands and dry coastal hills, except for a

Luasong, Sabah, Malaysia. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.

few records from swampy village margins near the coast; not recorded outside Sabah, but closely related if not conspecific rattans occur in Palawan and elsewhere in the Philippines. Endemic.

Description

Solitary or clustering robust rattan with stems climbing to 40 m or more; stem without sheaths 18-30 mm, with sheaths to 50 mm; internodes to 20 cm; stem surface smooth, yellowish, very even. Sheaths dull green with thin to abundant greyish indumentum, unarmed or very sparsely armed or densely armed with scattered horizontal fine black spines to 15 x 1 mm with pale swollen bases. Knee conspicuously unarmed. Ocrea forming a low ridge to 5 mm. Leaf cirrate, to 4 m including cirrus to 2 m, and petiole; petiole short in mature climbing stems, about 10 cm, longer in juveniles semicircular in cross section, the upper surface unarmed to densely armed with erect rigid black spines to 10 mm, the margins and mid line of lower surface also sometimes armed; leaflets about 25 on each side, regularly arranged ± pendulous when exposed, rather stiff, broadly lanceolate, the longest to 40 x 6.5 cm, rather conspicuously armed with black spines to 3 mm along the main veins on the upper surface and margins, especially near the tip, unarmed on the lower surface; transverse veinlets moderately conspicuous. Male and female inflorescences superficially similar, without terminal flagella, arching, to about 1 m with about 5 partial inflorescences, in the male branching to 2 orders, in the female to 1 order; male rachillae more crowded than in female, to 4Q x 1.5 mm, bearing distichous flowers; female rachillae to 120 x 3 mm, bearing rather distant flowers. Mature fruit rounded about 10 mm in diam., tipped with a beak to 1 x 1 mm, and covered in 15 vertical rows of pale greenish to ivory scales with pale brown margins. Seed about 7 x 6 x 5, deeply pitted, the pits penetrating the endosperm, which is thus subruminate. Seedling leaf forked. (J. Dransfield, The Rattans of Sabah. Sabah Forest Records 13.. 1984)/Palmweb. Editing by edric.

Culture

Cold Hardiness Zone: 10a

Comments and Curiosities

Etymology: Almost unarmed - From the Latin; the type specimen and some extant populations have almost unarmed leaf sheaths, but most populations are conspicuously spiny.

Uses: The best large diameter rattan native to Sabah. Were the stems of greater diameter, this would rival "rotan manau" (Calamus manan). Certainly a species of great economic potential, and one which requires urgent silvicultural assessment. Present stocks are limited and their exploitation requires strict control.