Dialium platysepalum
Content
Description
Trees, up to 45 m and 90-120 cm dbh; twigs greyish brown to rusty-brown, young parts brownish hairy.
Leaves including petiole (10-)15-24(-28) cm long; petiolules 2- 4.5 mm.
Flower buds up to 7.5 mm long, Sepals 5, triangular, to 6 by 4 mm, minutely hairy inside.
Stamens 2; filaments 1-2.5 mm long; anthers with both slits drawn towards the abaxial side, forming a V-channel on the abaxial side of the connective, 3 — 4( — 5) mm long, hairy.
Panicles terminal, the lower branches usually subtended by leaves, rachis 10 — 15( — 30) cm, usually rusty brown; pedicels (2-)2.5-4(-7) mm.
Ovary 2-3.5 mm long; style sharply recurved at top, up to c. 3 mm long, usually sparsely hairy on lower half.
Fruits sub- globose to obovoid, sometimes slightly compressed, (1.5-)2-2.5(-3) cm long, sometimes up to 2 mm stipitate; pericarp firm, exocarp densely brown velvety, persistent.
Seeds l(-2), roundish to reniform, 3-13 by 9 mm, testa light brown to blackish, shiny.
Distribution
Asia-Tropical: Borneo present; Malaya (Peninsular Malaysia present, Singapore present); Sumatera (Sumatera present)
Malesia: Peninsular Malaysia, Singapore, Sumatra, Borneo.
Taxonomy
By the size of the leaflets and colour and quality of the indumentum on their under- surface the species can be segregated into more or less discrete 'groups'. The 'maingayi' group has a rather whitish to slightly golden indumentum underneath, the nerves are not very distinct. The 'platysepalum' group is the most common group, but not easily separated from the previous one; the leaves are often tinged golden underneath. Leaves in the 'wallichii' group are slightly golden or light yellow beneath but the blades are smaller, not more than 7 by 2 cm. In the 'kingii' group leaves are slightly larger than in 'wallichii', the undersurface is golden to chocolate brown, the nerves are prominent. In the 'triste' group the chocolate brown leaves are still larger and the nerves much more prominent. The differences between the 'groups' are slight and they form a gradient with intermediate specimens, so they are given no taxonomic and nomenclatural status.
This species is distinct from all other species of Dialium. Mature flower buds as well as anthers are the largest in the genus. The base of the flower bud is usually incurved appearing distinctly zygomorphic, and the receptacle is deeply concave with filaments and ovary inserted excentrically on opposite sides.
Citation
Ridley 1922 – In: Fl. Malay Penins.: 624
Ridley 1922 – In: Fl. Malay Penins.: 623
Whitmore 1972 – In: Tree Fl. Malaya: 259.
Whitmore 1972: p. 261. – In: Tree Fl. Malaya: f. 7.
Ridley 1922 – In: Fl. Malay Penins.: 623
Cockb. 1976: Trees Sabah: 169: f. 35.
Ridley 1922 – In: Fl. Malay Penins.: 622
Whitmore 1972 – In: Tree Fl. Malaya: 261
Whitmore 1972 – In: Tree Fl. Malaya: 260.