Castanopsis acuminatissima (Blume) A.Dc.

Tree, 10-36 m by 30-90 cm ø; buttresses to 2 m tall, 1½ m out; bark greyish brown, rough, fissured, inner bark 1-2 cm thick, pale to reddish brown. Branchlets initially with a dense layer of rufous fimbriate scales and adpressed stellate hairs; slender, later glabrescent, with minute lenticels, greyish black, finely fissured, at the base with scars of the bud scales; terminal bud ovoid or flat-ellipsoid, mostly found when having attained a size of 4-8 by 2-3 mm, apparently waiting for some time before developing further, the scales imbricate or mostly distichous, membranous, ovate-acute, 1-1½ by 1-1.2 mm, densely hirsutely ciliate, persistent for some time. Stipules ovate-acute, 3-4 by 1 mm, caducous. Leaves thin-coriaceous, 4½-17 by 2½-6 cm (index 2.4-3.5 (-4)), widest at or below the middle; base rounded or attenuate, acute to sometimes decurrent, margin entire and undulate or remotely serrate in the apical half, top tapering and acuminate with sharp tip 1-2½ cm; surfaces discolorous, above glossy green, glabrous, underneath dull brown to sometimes silvery with a mostly thick cover of adpressed scales, no hairs; midrib and nerves prominent beneath, flattish or slightly sunken above; nerves 10-14 pairs at an angle of 45-60°, subparallel, ascending, arcuating and disappearing towards the margin, reticulation fine, scalariform or irregular, obscure on both surfaces; petiole ½-1 cm, adaxially flat. Inflorescences male, female, or androgynous. Male rachis 5-10 cm, slender with sparse simple hairs, bracts ovate-acute, membranous, 1-2 by 1-1½ mm, ciliate, bracteoles reduced to a cluster of simple hirsute hairs; ♂ flowers densely arranged but solitary, perianth lobes 6, almost free, ovate-rounded, 1-2 by 1½ mm, membranous, ciliate, stamens 12-14, filaments slender, 2-3½ mm, anthers 0.3-0.45 mm long, pistillode rudimentary, 1-1½ mm ø. Female and androgynous rachis 5-10 cm, slender, with sparse simple hairs, bracts ovate-acute, 1½-2 by 1-1.2 mm, membranous, densely ciliate, bracteoles 1 by 0.7 mm; androgynous rachis with a few ♂ flowers in the apical part; ♀ flowers solitary, perianth membranous, deeply incised, lobes 6,1-1.2 by 0.7 mm, densely hairy, staminodes 12, styles 3, recurved, cylindrical, 1-1½ mm, sparsely tomentose at the base. Young infructescence 10-15 cm, carrying 10-20 young cupules more or less ovoid-globose, sessile, enclosing the fruit except for the persistent perianth and styles, surface covered all over with scale-like appendages. Ripe cupule 1-1½ by 0.7-1.2 cm, (sub)sessile, more or less globose with the fruit partly emerging; wall ½-1 mm thick, inside sparsely hairy, outside densely grey-fulvous puberulous, rather densely set with acroscopical firm scales or small flat-triangular spines, irregular or in 5-7 ± regular transversal rows, to 2 mm long with a sharp glabrous tip or obtuse; dehiscence irregular or medianly into 2 equal segments. Fruit solitary, ovoid-conical, pointed, 1-1½ by ¾-1 cm, longitudinally ribbed (also in the fresh state?), scar flat or rounded, ± ¼ part, the remainder free, with dense rufous tomentum, glabrescent.

A tropical plant. It occurs throughout much of Papua New Guinea and can form pure stands in lower mountain rainforest between 500 and 2,000 m altitude. The most common place is between 1,100 and 2,300 metres above sea level but they can occur down to 500 metres in many places and are at the sea level. Often these chestnut trees are more common on the boundary between the grassland and the forest. They form a thick covering of leaves which stops many smaller plants from growing underneath. As well they commonly grow in groups or clumps made up only of chestnut trees. From planes, these Castanopsis forests can be picked out because they have a distinctive yellowish brown colour. Under the trees there is usually a thick layer of fallen leaves.

The seeds are eaten preferably after cooking. They are boiled. CAUTION Mouth ulcers and anaemia have been reported from eating large numbers of raw nuts. It is therefore safest to cook them. Small numbers of the nuts are eaten raw by children. Mostly the nuts are cooked and eaten. If small amounts are available they are boiled in a container. If large quantities are available they are cooked in earth ovens. Cooked they taste like rice. Pigs readily consume the nuts so people take their pigs out and tie them up under the trees in the bush during the nut season.

The seeds grow easily. Self sown plants can often be found under large trees. These can be transplanted to where you want to grow a tree. A nursery can be used by planting some seeds and then transplanting them when they are big enough. Although suckers are common near the base of trees they do not grow easily. Pollination is most probably by wind.