Tree 6-20 m. Leaves membranous, chartaceous, or thinly coriaceous, elliptic-oblong or oblong-lanceolate, 11-30 by 3.5-10 cm, base rounded or short-acute, apex acute or acute-acuminate; Inflorescences among the leaves, pedunculate, branched; Fruits 1 or 2 per infruc-tescence, ± ellipsoid, (4.5-)5-7.5 by 3-4.5 cm, indumentum persistent or late glabrescent, hairs dark cinnamon, mealy, 0.1 (-0.3, see note 2) mm;
Asia-Tropical: Borneo present (Brunei present, Sabah present, Sarawak present), W & C Kalimantan present
Malesia: Borneo (Sarawak; Brunei; Sabah, rare; W & C Kalimantan).
2 Two forms of indumentum can be distinguished, one with very short hairs, 0.1 mm, on apical bud, inflorescences and flowers and with the lower leaf surface early glabrescent (most of the specimens), and another form with the indumentum more conspicuous and persistent, with dark brown hairs, 0.1-0.3 mm. In most collections the fruits have scurfy hairs 0.1 mm long or less, but in very immature fruits the indumentum may be longer, 0.2-0.4 mm (longer hairs later on apparently shed). The infructescence is short, 1-2 (-3.5) cm long. 3 The specimen BRUN 577 (Ashton) has a not or but indistinctly papillose lower leaf surface, but there are many minute, scattered, dark brown dots, possibly cork-warts, absent in other specimens. SAN 36839 (Beaufort Dist., Sabah) has stout twigs and broad fruits, 5 by 4 cm; the twigs dry blackish brown; the leaves are chartaceous, with acute-acuminate base, the lower surface not very distinctly papillose, and small scattered scalelike hairs virtually absent; this specimen may have to be excluded from M. borneensis. 1 Myristica borneensis may be confused with M. malaccensis which differs in its olivaceous-brown leaves on drying, subcircular bracteoles with ciliate margin, (subglobose-)ovoid glabrescent male buds, cleft 1/4-1/3, with thin lobes, 0.3 mm thick, androecium consisting almost entirely of the synandrium with a sterile apex lacking or with the apex of the synandrium hollowed, glabrous androphore, and (almost) glabrous fruits.