Macaranga pearsonii (Miq.) Merr., Philip. J. Sci. 29 (1926)

Named after ?

Diagnostics
Upper canopy trees up to 43 m tall and 86 cm dbh. Twigs usually hollow and ant inhabited, stipules only slightly recurved, up to ca. 9 mm long. Leaves alternate, simple, 3-lobed, sometimes peltate, tripli- to palametly-veined, base usually cordate with several large glands on the margin. Flowers ca. 0.5 mm diameter, green-yellowish, placed in bundles within bracts which are part of large panicles. Fruits ca. 6 mm diameter, greenish, 2-lobed, dehiscent capsules, seeds with red aril.

Description
Large tree to 35(-43) m tall and 50(-86) cm dbh, often smaller in open areas; twigs 6-12 mm in diam., glabrous, usually densely glaucous, hollow, housing ants. Bark pale whitish-grey to light brown, smooth, hoop marked. Stipules broadly ovate, 9-14 by 9-13 mm, erect to saccate, glabrous, the pair not completely encircling the twig, coriaceous, producing food-bodies on the upper surface, up to 3 pairs present on the shoots. Leaves: petioles terete, slender, 10-30 cm long, glaucous towards the base, finely pubescent towards the apex; blades ovate to very broadly ovate, 13-28 by 13-30 cm, deeply trilobed, dissected to c. 1/2 of the leaf length rarely somewhat less, lateral lobes 1/2 to 4/5 the size of the central lobe, not peltate or sometimes to 10 mm peltate, base broadly rounded, cordate, margin entire, usually with 1-6 prominent conical nectaries at the leaf base adjacent to the petiole insertion, apices shortly acute, adaxial surface glabrous or scattered with minute ferrugineus hairs along the veins near the petiole insertion, abaxial surface densely minutely furfuraceous tomentose on the veins and scattered with long erect silvery hairs and densely glandular punctate; 1st degree venation palmate with 5 prominent veins, 5-9 subprominent veins running from the petiole insertion to the basal leaf margin, 2nd degree venation scalariform terminating at the margins in prominent conical nectaries or looping just before the leaf margins, 3rd-4th degree venation densely scalariform, finest nerves densely reticulate; young leaves reddish brown, upper surface densely covered in fine ferrugineus hairs, lower surface with dense erect silvery hairs. Staminate inflorescences paniculate, erect, 15-40 by 10-25 cm, all axes densely covered in erect silvery hairs, the basal axis sometimes glabrous, to 4 axis orders, main axis flattened, first pair of sec-ondary branches +/- opposite without accessory branches; bracts narrowly ovate, 5-10 by 3-6 mm, margin entire, apex acute, glabrous or with scattered silvery hairs on the margins, persistent; flower clusters with c. 10 flowers, spially arranged on inflorescence branches; bracteoles ovate-elliptic, 3-6 by 2-4 mm, enclosing flower clusters, margin deeply irregularly dissected, apex acute to acuminate, veins slightly raised on the abaxial surface, both surfaces densely covered with fine silvery and reddish brown hairs. Staminate flowers c. 1 mm long, pedicellate; sepals free, apex densely covered in minute red-brown hairs; stamens 2-3; anthers 4-locular. Pistillate inflorescences paniculate, erect, 8-25 by 8-16 cm, densely branched, finely silvery pubescent throughout, up to 3 axis orders; bracts ovate, 5-10 mm long, margin entire, glabrous or with scattered hairs on the margins, caducous. Pistillate flowers c. 1.5 mm long, solitary in bract axils; calyx urceolate, c. 1 mm long, scattered with fine silvery and ferrugineus hairs, persistent; ovary 2-carpellate, c. 1 mm long; styles c. 1 mm long, free, persistent; stigma not dissected. Fruits 3-4 by 5-6 mm, bilocular, locules globose, pedicellate, evenly covered in sticky glandular exudate, without processes; pedicel 4-7 mm long, densely pubescent. Seeds lenticular, c. 2.5 mm in diam., black, with shallow grooves, encased in a fleshy pale purple aril. [from Flora Malesiana]

Ecology
Mainly in disturbed sites in mixed dipterocarp, keranga and sub-montane forests, but since it can become so large it is sometimes found in seemingly undisturbed sites. Most common in degraded forest, scrub and roadsides up to 1500 m altitude. Often on hillsides and ridges with sandy to clay soils.

Distribution
Borneo.

Local names
Borneo: Nangsang batu, Sadman.