Horsfieldia pallidicaula W.J.deWilde, Gard. Bull. Sing. 38 (1986)

Synonyms
Horsfieldia bracteosa var. microcarya J.Sinclair

Diagnostics
Sub-canopy tree up to 26 m tall and 32 cm dbh. Stem with red sap. Stipules absent. Leaves alternate, simple, penni-veined, glabrous. Flowers ca. 3 mm diameter, yellow, placed in panicles. Fruits ca. 32 mm diameter, orange-pink, glabrous, dehiscent capsules. Seeds with undivided pinkish-orange aril.

Description
Tree 7-20(-26) m. Twigs 2-10 mm diameter, pale, whitish or greyish brown, contrasting with the blackish drying colour of the petioles (which often are greyish and sometimes flaky in the lower half), early glabrescent, hairs grey-brown, 0.1-0.3 mm long; bark finely striate, slightly flaking or not; lenticels inconspicuous or absent. Leaves either in 2, 3, or 5 rows, membranous, oblong(-lanceolate), 10-30 by 4-9.5 cm, base long-attenuate, apex acute-acuminate; upper surface drying (blackish) brown, lower surface drying (grey-)brown, early glabrescent; dots absent; midrib slightly raised above, glabrous; nerves 10-18 pairs, slender, flat or slightly raised above, lines of interarching indistinct; venation lax, indistinct; petiole 10-25 by 1.5-3 mm; leaf bud stout or slender, 7-10 by 2-4 mm, with brown-grey or rusty hairs (0.1-)0.2(-0.3) mm long. Inflorescences generally behind the leaves, glabrescent, hairs sparse, 0.1-0.2 mm; in male: (2 or) 3 times branched, many-flowered, 3-9 by 2.5-7 cm, peduncle up to 0.7 cm long (inflorescences often branched from near the base), the flowers in loose clusters of 2-4; in female: rather few-flowered, 1-3 cm long; bracts lanceolate, acute, finely pubescent, 1-3 mm long, caducous; flowers glabrous, perianth 3- or 4-lobed, in female sometimes 2-lobed, pedicel not articulated. Male flowers: pedicel 1-2 mm, slender; buds globose or broadly obovoid, 1.5-2(-2.2) mm diameter, base rounded to short-attenuate, cleft c. 1/3 to nearly 1/2, not or but slightly collapsing on drying, lobes 0.2-0.3 mm thick; androecium short-ellipsoid or depressed-globose, 0.8-1.2 by 0.8-1.2 mm, circular in cross section, thecae 16-20, completely sessile (free apices 0.1 mm long), incurved towards the apex of the androecium; column broad with narrow apical cavity, 0. 1-0.2 mm deep; androphore narrow, 0-0.2 mm long. Female flowers: pedicel 1-1.5 mm long; buds broadly ellipsoid or subglobose, 2.5-3 by 2.5 mm, cleft 1/4-1/3; ovary broadly ovoid, 1.7-2 by 1.5-2 mm, glabrous, stigma lobes 0.1-0.2 mm long. Fruits 1-5 per infructescence, broadly ellipsoid, 1.5-6 by 1-3 cm, glabrous, drying blackish, finely granulate and sometimes tubercled; pericarp variable; fruiting pedicel 1-3 mm long; perianth persistent under the fruits (always?). [from Flora Malesiana]

Ecology
In undisturbed mixed dipterocarp and keranga forests up to 700 m altitude. Common along rivers and streams, but also on hillsides and ridges. On clay to sandy soils.

Distribution
Borneo.

Local names
Borneo: Kumpang, Kumpang balau.