Dactylocladus stenostachys Oliv.

Tree up to 40 m, dbh up to 1¼ m, at the base producing pneumatophores. Twigs often several together per leaf-axil, the younger ones often with ribbed angles. Leaves 4-8(-16) by 2½--4(-6) cm, with revolute margin, cuneate at the base, sometimes emarginate, usually rounded up to acuminate at the top with acute tip, coriaceous; nerves 11-15 pairs, usually rather obscure, flat to prominulent above and beneath; petiole 3-5 mm, 2-3 mm Ø. Inflorescence when axillary 1-3 together, erect, up to 14cm, consisting of 3 racemules; peduncle up to 6 cm, (sub)glabrous; axes finely ribbed; racemules c. 8 cm, from 1 cm above the base ± densely set with flowers. Bracts of axes minute, soon caducous. Bracts of the flowers linear or narrowly triangular, c. 1 mm. Pedicels up to ½ mm. Receptacle c. 2 mm high, c. 2½ mm wide. Sepals c. 1 mm. Petals c. 1 mm, puberulous outside and on the margin. Filaments c. 1 mm, 0.2 mm wide, puberulous; connective ¼-1½ mm; anthers 0.2 by 0.1mm. Style 1½-2mm, c. 0.2 mm Ø; stigma ¼-½ mm. Capsule 3-4 by 2-3(-3½) mm. Seed c. 1.4 by 0.2-0.3 mm, including wing 2½-3 by ¾-1¼ mm.

DURANT ( DURANT For. Rep. Brunei 1933 6 photogr. ) reported this species (under the name Crypteronia) to occur in Brunei as an associate of Dryobalanops and Combretocarpus in considerable quantity over large areas of freshwater swamp, often with 12 mature trees (over 30 cm Ø) per ha. DIELS & HACKENBERG (l.c) mentioned its occurrence in the Sampit swamp forest area in SW. Borneo together with Combretocarpus, Campno-sperma, etc. BROWNE (l.c.) stated that it occurs in practically all types of peat swamp forest in Sarawak. He found its frequency somewhat lower than DURANT did; he found sometimes 8, but averagely 3 mature trees per ha, but he said that locally, between Balingian and Bintulu, it was the dominant tree of the swamps of Sarawak.BROWNE recorded that the vernacular names jongkong and tabak allude to characteristic qualities: jongkong referring to the rather stout yellowish pneumatophores at the stem-base, while tabak would refer to the characteristic minute perforations of the wood from radial vessels.ANDERSON (l.c) confirmed BROWNE'S observation that it is one of the most characteristic swamp forest trees, the only species represented in all communities throughout Sarawak and Brunei. He produced photographs of the Gonystylus-Dactylocladus-Neoscortechinia (l.c. pi. 1 & 2) and the Combretocarpus-Dactylocladus associations (l.c. pl. 6 & 7).Its wide range in the peat swamps is also confirmed palynologically in the peat according to ANDERSON & MULLER (Rev. Palaeobot. & Palyn. 19, 1975, 314-316) where it figures in phases 1-6. In a Miocene deposit in Brunei, near Berakas, MULLER reported also its occurrence (l.c. f. 5, diagram) with the associates as today. It must be added that its pollen can be confused with that of Axinandra and some Melastomataceae of which the latter also occur in peat swamps, albeit in small numbers.It is remarkable that whereas this type of peat forest ranged unbrokenly at least from the Miocene to the Present, Dactylocladus is not yet found in Sumatra and Malaya, provinces with which Borneo was joined, during the Pleistocene Glacial period, by a huge lowland riverine area (now the South China Sea); this would have made dispersal and exchange very probable, as it was for its associate Combretocarpus and some species of Gonystylus. It may yet be discovered in the peat swamps of Malaya and Sumatra, but must then be very rare.

Uses. According to BROWNE (l.c.) it is the fourth important export timber tree of Sarawak. Extraction is facilitated by the fact that the logs float in water. MEIJER (l.c.) termed it a general utility timber in Sabah where it is, besides Gonystylus, the most important export timber from the Klias Peninsula.

Can be grown by seedlings.